This document discusses electrical safety in power distribution. It identifies hazards that can lead to electrical accidents, such as faulty wiring, damaged insulation, and improper training. The document advocates applying a hazard management process to identify electrical hazards, assess their risks, implement control measures, and establish recovery plans in case controls fail. The goal is to reduce electrical accidents and promote a safe working environment.

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ELECTRICAL SAFETY IN
POWER DISTRIBUTION
BY
EZE, MONDAY NDUBUISI
08084501883, 07068301351
IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE
MEMBERSHIP OF INSTITUTE OF SAFETY PROFESSIONALS OF
NIGERIA
SEPTEMBER, 2014.

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ABSTRACT
While there are many circumstances that can lead to an electrical accidents, it is helpful to identify
and document known hazardous conditions that can occur in electrical facilities and equipment.
Conditions that can be reproduced in a laboratory, intended to duplicate real-life conditions, can be
used to increase knowledge of the possible hazards and as a guide for manufacturers to develop safer
and more fire resistant electrical systems. The need for electrical energy which has grown drastically
high, due to advancement in technology, which are mainly electrically driven. This advancement has
equally bring about high electrical accidents, due to unsafe working condition and unsafe practices
at work. Hence, the need to reduce the accident at work become a necessity in order to increase
productivity and making environment safe for the workers. The first stage in electrical hazard effect
management process is to identify the associated hazards in different tasks related to electrical
engineering and other industries that electrical power is of great need to drive the machineries. After
this has been done, it is pertinent to evaluate or access the extent of the damage the hazard could
cause, this will enable the operators of the facilities to put in place control measures base on
hierarchical level of controls, in the to enhance the control measures a recovery measures is put in
place as back up, in case the control measure fails.

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ACKNOWLEDGEMENT
With much pleasure and gratitude, I extend my sincere thanks to the Almighty God and all those
that helped me in all the activities leading to this project, both in their individual and institutional
Capacities. I will forever be indebted for their cooperation and support. It is hardly possible to
thank them individually here.
My heartfelt gratitude goes to my sponsor, Mr. Sunday Akinbode Ogungbe, Managing Director
of Paper House Limited for his guidance, kind gestures and his support to me .Special thanks also
go to Dr. Wilson Arikpo , Public Relation Officer of Institute of Safety Professionals of Nigeria
(ISPON). I wish to thank the Head of Electrical/ Electronics Engineering Department, Prof
Adegbenro and the staff of University of Lagos, Electrical Department.
My profound gratitude goes to my mother, Mrs. Elizabeth Eze for her prayers and financial
Support. Thank You All!!

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LIST OF FIGURES
Figure 1……………………………………………………Electrical Burn
Figure 2……………………………………………………………...A Fuse
Figure 3……………………………………………………Circuit Breaker
Figure 4…………………………………...Arc Fault Circuit Interrupters
Figure 5………………………………Ground Fault Circuit Interrupters
Figure 6…………………………………..Earth Leakage Circuit Breaker
Figure 7………………………………………………….Guarding System
Figure 8…………………………………………………..Earthing System
Figure 9………………………………………………………Disconnector
Figure 10…………………………………………………...House Keeping

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CHAPTER 1
ELECTRICITY
1.1 Introduction
Electricity is the set of physical phenomena associated with the presence and flow of electric
charge. Electricity gives a wide variety of well-known effects, such as lightning, static electricity,
electromagnetic induction and electrical current. In addition, electricity permits the creation and
reception of electromagnetic radiation such as radio waves.
In electricity, charges produce electromagnetic fields which act on other charges. Electricity occurs
due to several types of physics:
 electric charge: a property of some subatomic particles, which determines their
electromagnetic interactions. Electrically charged matter is influenced by, and produces,
electromagnetic fields.
 electric potential: the capacity of an electric field to do work on an electric charge, typically
measured in volts.
 electric current a movement or flow of electrically charged particles, typically measured in
amperes.
 electromagnets: Moving charges produce a magnetic field. Electrical currents generate
magnetic fields, and changing magnetic fields generate electrical currents.
 electric field: is created by a charged body in the space that surrounds it, and results in a
force exerted on any other charges placed within the field.
 electrochemistry: The ability of chemical reactions to produce electricity, and conversely
the ability of electricity to drive chemical reactions has a wide array of uses.
 electric circuit: is an interconnection of electric components such that electric charge is
made to flow along a closed path (a circuit), usually to perform some useful task.
 electric power: electric power is the rate at which electric energy is transferred by an
electric circuit. The SI unit of power is the watt, one joule per second.
 electronics: electronics deals with electrical circuits that involve active electrical
components such as vacuum tubes, transistors, diodes and integrated circuits, and
associated passive interconnection technologies.

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1.2 Problem Statement
Hospital Emergency Rooms provide life-saving measures to tens of thousands of individuals
injured/maimed/impaired as a direct/indirect result of the effects of electric current passing through
their bodies usually through a careless act. Over a thousand individuals are electrocuted annually.
Electrical accidents in the home and on-the-job are initiated as a result of improper use and care
of electrical equipment, extension cords, and plugs. Causes for these events include inattention
through repetition, unexpected and inexperience and overconfidence. We can eliminate a large
percentage of these injuries and death through the application/use of safe tool/electrical practices.
1.3 Objectives
The aim of the study of electrical safety covers both the applications of electrical energy at
industrial and domestic level. The objectives are
 To identify hazards that could lead to electrical accident
 To access the hazards surrounding electrical works/task
 To put in place control measures necessary to curtail the electrical accident likely to
occur.
 To be able to put in place recovery measures in case the control measures fails
 To educate workers on safety tips in an electrical environment
1.4 Motivation
The passion to research on electrical safety can be link to professional experience in defunct Power
Holding Company of Nigeria, where I worked as an Industrial Trainee Student in Operation and
Maintenance department, Protection, Control and Metering department where safety is imperative
even though it was not fully practice.
1.5 Scope of Study
The project cover details about electricity from the history, applications , the hazards in electricity,
management of electrical hazards, application of Hazards Effect Management Process (HEMP)
to electrical hazards, safety tips and practices that can enhance safety of workers , managing the
risks of electrical work, electrical working a confined spaces , safe work method statement, low

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voltage isolation and access , safety in restoring power, risk controls on energized and de-energized
electrical works, importance of earthing system to electrical safety, proper house keeping.
1.6 Brief History
Electrical phenomena have been studied since antiquity, though progress in theoretical
understanding remained slow until the seventeenth and eighteenth centuries. Even then, practical
applications for electricity were few, and it would not be until the late nineteenth century that
engineers were able to put it to industrial and residential use. The rapid expansion in electrical
technology at this time transformed industry and society. Electricity's extraordinary versatility
means it can be put to an almost limitless set of applications which include transport, heating,
lighting, communications, and computation. Electrical power is now the backbone of modern
industrial society.
1.7 Applications
In electrical engineering, electricity is used for:
• electric power where electric current is used to energise equipment;
• electronics which deals with electrical circuits that involve active electrical components
such as vacuum tubes, transistors, diodes and integrated circuits, and associated passive
interconnection technologies.
1.8 The Hazards of Electricity
Electricity is invisible - this in itself makes it dangerous. It has great potential to seriously injure
and kill. The average can receive critical injuries as a result of even very short exposures to
everyday 240-volt single-phase alternating current supply voltages. Major electrical risks exist
when insulation protection is not maintained in a safe condition or is placed in a hostile
environment causing it to fail.
It must also be remembered that there are other electrical hazards and risks with potentially fatal
consequences where a residual current device or safety switch might be inoperative. This can occur
when the electrical plant has a fault and there is contact by the operator between the active
(positive) and the neutral (negative) conductors forming a short circuit through the body with no
leakage to earth, and therefore insufficient residual current for the RCD to operate. It is therefore

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necessary to manage workplace electrical safety as an integral part of day-to-day operations in
order to ensure the integrity of electrical installations and electrical plant.
1.9 Management of Electrical Hazards
General principles One of the general principles in implementing the Occupational Health Safety
and Welfare Regulations, 1995, is ‘hazard management’. Hazard management consists of four
stages. Those stages are hazard identification, risk assessment and risk control and recovery
measures.
1.9.1 Hazard Identification
A hazard is something that has the potential to harm the health, safety and welfare of people at
work. Examples of electrical hazards that may be found in the workplace include frayed flexible
supply cords, cracked electrical plant covers, flexible supply cords which have been run over by
vehicles, electrical plant used in wet areas and electrical plant which is moved frequently such as
vacuum cleaners. These are all considered electrical hazards. To identify hazards to health, safety
and welfare:
• Check records of injuries and incidents (including near misses) that have occurred in the
workplace or in other similar workplaces.
• Read publications such as OHSW and Electrical Regulations, Codes of Practice, Guidelines
from IEEE.
• Conduct walk-through inspections of the workplace using a checklist to identify potential
electrical hazards. This checklist may include, but is not limited to, checking all flexible supply
cords, electrical plant, the way the electrical plant is used and the areas that it is used in.
• Ask employees if they have ever experienced problems with electrical plant to identify
electrical hazards. Hazard identification should be an integral part of workplace culture. This
involves regular workplace inspections in consultation with employee representatives and
encouraging employees to report any hazardous situations that may occur in the workplace.

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1.9.2 Risk Assessment
When hazards have been identified, the risk associated with each hazard needs to be assessed to
evaluate the probability and consequences of injury, illness or disease arising from exposure to an
identified hazard or hazards. When performing a risk assessment consider the following:
• the nature of the hazard
• how it may affect health and safety
• the likelihood that the hazard will cause injury, illness or disease, (how much, how often and
how long employees are exposed).Put simply, the identification of a frayed and worn electrical
cable on an appliance is the identification of a hazard. An appreciation of the associated risk, that
is, a risk that is likely to cause serious injury or a fatality, is an example of risk assessment. Clearly
such a situation would require immediate action, which would include removing the faulty item
from service until it can be replaced or repaired. This is a form of risk control, which will be
covered in more detail in the following stage. The risk assessment also takes into account the way
that the work is organised, the layout and condition of the work environment, the training and
knowledge needed by the person to perform the work safely and the type of control measures that
are available. The assessment of risk is a process of gathering information and making decisions.
There is no single correct answer, as people will make certain decisions about the risk because
they have different ideas about what is acceptable. For this reason it is important that those who
will be affected by the decisions made (the employer, relevant employees and their representatives)
should be involved in the assessment.
1.9.3 Risk Control
When hazards have been identified and the risks assessed, appropriate control measures should be
developed and implemented. The aim is to eliminate or minimise the risk. There are many ways
for employers to control risks to health and safety in the workplace. As far as possible a hazard
should be controlled at its source rather than trying to make the employee ‘work safely’ with
dangerous electrical plant or in a dangerous environment. Controlling the hazard at the source is
much more effective in the prevention of injury, illness or disease. To do this, action needs to be
taken to control risks through a preferred sequence of risk control programs.

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1.9.4 Recovery Measures
Once the control measures have been implemented it is important to evaluate how effective those
measures have been. This is performed by simply re-assessing the risks associated with the hazard
and establishing whether the controls have eliminated or minimised the risk of injury, illness or
disease. And if the control measures fail, contingency plan are on ground such as:
 provision of first aid kits
 emergency response team such as ambulance service
 fire fighting equipment such as fire extinguisher.
 Regular fire drill at the operational station.
 Training and continuous re- training of staffs
1.9.5 Review
A review of the hazard management process should be performed at regular intervals. This can be
part of a regular inspection or when work practices or the work environment changes, to ensure no
new hazards have been introduced.

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CHAPTER 2
ELECTRICAL HAZARDS
2.1 Introduction
Electrical hazards are caused by the improper use of machinery or apparatus, electrical outlets,
electrical equipment, such as cables and power cords the improper maintenance of apparatus,
outlets, and electrical equipment. When used or maintained improperly, electrical equipment or
devices can overheat or produce electrical fires. Frayed cords or exposed wires can easily electrify
you or your students. Causes of hazards are:
 apparatus with deteriorated power cord insulation
 a bent or broken prong on a plug
 a broken prong on a plug protruding from an outlet
 an overloaded circuit
 flammable fumes near electrical apparatus
 metal tools used near energized conductors
 dangling jewelry near an energized conductor
 a circuit that someone is working on with both hand water spill on electrical equipment
2.2 Types of Electrical Hazards are, namely
 Electrical Shock
 Electrical Burns
 Fall
 Electroocution
 Electrical Fire
 Arc blast
 Heart failure
2.2.1 Electrical Shocks
Electricity travels in closed circuits, and its normal route is through a conductor. Electric shock
occurs when the body becomes a part of the electric circuit. The current must enter the body at one
point and leave at another. Electric shock normally occurs in one of three ways. Individuals-while
in contact with the ground- must come in contact with both wires of the electric circuit, one wire

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of an energized circuit and the ground, or a metallic part that has become "hot" by contact with an
energized conductor. The metal parts of electric tools and machines may become energized if there
is a break in the insulation of the tool or machine wiring. The worker using these tools and
machines is made less vulnerable to electric shock when there is a low-resistance path from the
metallic case of the tool or machine to the ground. This is done through the use of an equipment
grounding conductor a low resistance wire that causes the unwanted current to pass directly to the
ground, thereby greatly reducing the amount of current passing through the body of the person in
contact with the tool or machine. If the equipment grounding conductor has been properly
installed, it has a low resistance to ground, and the worker is protected.
Severity of the Shock
The severity of the shock received when a person becomes a part of an electric circuit is affected
by three primary factors: the amount of current flowing through the body (measured in amperes),
the path of the current through the body, and the length of time the body is in the circuit. Other
factors that may affect the severity of shock are the frequency of the current, the phase of the heart
cycle when shock occurs, and the general health of the person. The effects of electric shock depend
upon the type of circuit, its voltage, resistance, current, pathway through the body, and duration of
the contact. Effects can range from a barely perceptible tingle to immediate cardiac arrest.
Although there are no absolute limits or even known values that show the exact injury from any
given current, the table shows the general relationship between the degree of injury and amount
of current for a 60-cycle hand-to-foot path of one second's duration of shock.
Electrical hazards can burn equipment and cause a fire in your Classroom or house these hazards
can also cause serious injuries to you or your students. Specifically, current passing through a body
may produce one or more of the following symptoms:
 Shock should not be confused with electric shock. Shock is an excitation or disturbance of
the normal function of nerves or muscles.
 Involuntary muscle reaction: a person who experiences an electric shock may not be able
to control her or his muscles. In addition, muscles that a person normally does not control,
such as the heart, may operate abnormally.
 Muscle paralysis: an electric shock may prevent muscles from moving (for example, arm
muscles cannot flex) or operating (for example, the heart cannot pump blood).

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 Burning of tissue and organs Tissue and organs may be burned so badly that they
hemorrhage.
 Death (electrocution): Death can result from electrocution, which is caused by electric
shock.
2.2.2 Electrical Burns
Electrical burns can be caused by a variety of ways such as touching or grasping electrically live
objects, short-circuiting, inserting fingers into electrical sockets, and falling into electrified
water. Lightning strikes are also a cause of electrical burns, but this is a less common event.[8]
With
the advances in technology, electrical injuries are becoming more common and are the fourth
leading cause of work-related traumatic death. One third of all electrical traumas and most high-
voltage injuries are job related, and more than 50% of these injures result from power line contact.
Electrical burns can be classified into six categories, and any combination of these categories may
be present on an electrical burn victim:
 Low-voltage burn. A burn produced by contact with a power source of 500 volts or less is
classified as a low-voltage burn. The current at this voltage is not enough to cause tissue
damage along its path except at the contact site. This type of burn may be mild, superficial, or
severe depending on the contact time.
 High voltage burn. This burn is very severe as the victim makes direct contact with the high
voltage supply and the damage runs its course throughout the body. Exterior injuries are
misleading as most of the damage occurs underneath the skin. In this case, sub dermal tissues
are severely damaged.
 Arc burn:No contact is required with an arc burn as the electricity ionizes air particles to
complete the circuit. The heat generated can be as high as 4,000 degrees Celsius - hot enough
to vaporize metal and ignite a victim’s clothing. A form of explosion dissipates excess energy
from the arc. In addition, a high-amperage arc can produce a pressure wave blast in excess of
1000 pounds per square inch of pressure. This can throw the victim and cause severe injuries.
 Flash burn. Flash burns are caused by electrical arcs that pass over the skin. The intense heat
and light of an arc flash can cause severe burns. Although the burns on the skin are largely
superficial and cover a large area, tissues beneath the skin are generally undamaged and

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unaffected. This typically occurs when the frequency of the AC current is significantly higher
than the 50 or 60 Hz used in land-based electrical distribution systems (such as in aircraft).
 Flame burn. Flame burns are caused by Low-voltage burn. A burn produced by contact with
a power source of 500 volts or less is classified as a low-voltage burn. The current at this
voltage is not enough to cause tissue damage along its path except at the contact site. This type
of burn may be mild, superficial, or severe depending on the contact time. .
 Oral burns. This is caused by biting or sucking on electrical cords, and it most commonly
happens to children. Electrical current typically passes from one side of the child’s mouth to
the other, possibly causing deformity.
Figure 1: electrical burn
The most common shock-related injury is a burn. Burns suffered in electrical accidents may be of
three types: electrical burns, arc burns, and thermal contact burns. Electrical burns are the result of
the electric current flowing through tissues or bone. Tissue damage is caused by the heat generated
by the current flow through the body.
Electrical burns are one of the most serious injuries you can receive and should be given immediate
attention. Arc or flash burns, on the other hand, are the result of high temperatures near the body
and are produced by an electric arc or explosion. They should also be attended to promptly.
Finally, thermal contact burns are those normally experienced when the skin comes in contact with
hot surfaces of overheated electric conductors, conduits, or other energized equipment.
2.2.3 Fall
Each employee on walking/working surfaces must be protected from falling through holes
(including skylights) more than six feet above lower levels. Each employee on a walking/working
surface must be protected from objects falling through holes (including skylights) and from

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tripping in or stepping into holes (including skylights) by covers and falling from height above the
ground level . Wall openings: Each employee working on, at, above, or near wall openings
(including those with chutes attached) where the outside bottom edge of the wall opening is six
feet or more above lower levels and the inside bottom edge of the wall opening is less than 39
inches above the walking/working surface, must be protected from falling. Established floors,
mezzanines, balconies, and walkways. Each employee on established floors, mezzanines,
balconies, and walkways, with an unprotected side or edge six feet or more above a lower level,
must be protected from falling. Each employee at the edge of an excavation six feet or more in
depth must be protected from falling when the excavations are not readily seen because of plant
growth or other visual barrier. Each employee at the edge of a well, pit, shaft, and similar
excavation six feet or more in depth must be protected from falling. Each employee must be
protected from falls into or onto dangerous equipment, regardless of the fall distance. When an
employee is exposed to falling objects, the employer must have each employee wear a hard hat
and must implement an additional measure of protection such as erecting toe boards, screens, or
guardrail systems; or erect a canopy structure; or barricade the area and prohibit employees from
entering the barricaded area.
2.2.4 Electrical Arcing
In addition to the explosive blast, called the arc blast of such a fault, destruction also arises from
the intense radiant heat produced by the arc. The metal plasma arc produces tremendous amounts
of light energy from far infrared to ultraviolet. Surfaces of nearby objects, including people, absorb
this energy and are instantly heated to vaporizing temperatures. The effects of this can be seen on
adjacent walls and equipment - they are often ablated and eroded from the radiant effects.
2.2.5 Electrocution
Electrocution is death caused by electric shock, either accidental or deliberate. The word is derived
from "electro" and "execution", but it is also used for accidental death. The term "electrocution,"
coined about the time of the first use of the electric chair in 1890, originally referred only to
electrical execution and not to accidental or suicidal electrical deaths. However, since no English
word was available for non-judicial deaths due to electric shock, the word "electrocution"
eventually took over as a description of all circumstances of electrical death from the new
commercial electricity.

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2.2.6 Electrical explosion
A high current electrical fault can create an 'electrical explosion' by forming a high
energy electrical arc which rapidly vaporizes metal and insulation material. This arc flash hazard
is a danger to persons working on energized switchgear. Also, excessive magnetic pressure within
an ultra-strong electromagnet can cause a magnetic explosion.
2.2.7 Electrical Fires
Electrical fires are fires involving potentially energized electrical equipment. The US system
designates these "Class C"; the Australian system designates them "Class E". This sort of fire may
be caused by short-circuiting machinery or overloaded electrical cables. These fires can be a severe
hazard to fire fighters using water or other conductive agents: Electricity may be conducted from
the fire, through water, to the fire fighter's body, and then earth. Electrical fire have caused many
firefighter deaths.
Electrical fire may be fought in the same way as an ordinary combustible fire, but water, foam,
and other conductive agents are not to be used. While the fire is or possibly could be electrically
energized, it can be fought with any extinguishing agent rated for electrical fire. Carbon dioxide
CO2, FM-200 and dry chemical powder extinguishers such as PKP and even baking soda are
especially suited to extinguishing this sort of fire. PKP should be a last resort solution to
extinguishing the fire due to its corrosive tendencies. Once electricity is shut off to the equipment
involved, it will generally become an ordinary combustible fire.
.

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CHAPTER 3
MANAGING THE RISKS OF ELECTRICAL WORK
3.1 What Is Electrical Work?
Electrical work means connecting electricity supply wiring to electrical equipment or
disconnecting electricity supply wiring from electrical equipment. Installing, removing, adding,
testing, replacing, repairing, altering or maintaining electrical equipment or an electrical
installation. In the course of carrying out any electrical work either low or high voltage, hazard
management process should be carried out on the job/task to be done. They are;
 identify the hazards.
 access the risks
A risk assessment involves considering what could happen if someone is exposed to a hazard and
the likelihood of it happening. Risks associated with electrical work may arise from:
 the properties of electricity, electricity is particularly hazardous because electrical currents
are not visible and do not have any smell or sound.
 how and where the electrical work is carried out. Electrical work may be carried out in
difficult conditions, including in wet weather conditions, confined spaces and in
atmospheres that present a risk to health and safety from fire or explosion.
 the competence of the persons carrying out the electrical work.
If energised or ‘live’ electrical work is proposed to be carried out, a risk assessment must be
undertaken before the work starts and it must be carried out by a competent person and recorded.
The following risk factors associated with carrying out electrical work should be considered:
 sources of electrical risks, including energy levels at the workplace
 the nature of the electrical work to be carried out
 potential or actual high fault current levels (i.e. risks associated with arc flash)
 availability of isolation points
 work practices
 the type of plant, machinery and equipment to be used
 availability of suitable test instruments
 availability of properly rated PPE

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 the workplace and working environment, for example:
 wet weather conditions in and around trenches, pits and underground ducts
 ladders, scaffolds, portable pole platforms, elevating work platforms, poles and towers
3.2 Electrical Work in a Confined Spaces
The followings must be considered before electrical work is carried out in a confined space;
 ability to safely rescue persons.
 the competence of people carrying out the work, noting that licensing requirements may
apply for the electrical work under local electrical safety laws.
Also consider individual workers’ needs, for example;
 Is the worker experienced in, and have they been properly trained for, the working
conditions?
 Is the worker physically fit for the proposed work, for example are they able to climb to
heights to work on an overhead conductor or are they mentally alert and not fatigued?.
 Does the worker have a visual or hearing impairment, for example do they have a visual
colour deficiency or hearing loss?
 Does the worker take any medication that may increase their vulnerability to work in
electrical environments?
 Is the worker working excessively long hours?
 Does the worker suffer from claustrophobia?
3.3 Control the Risks
Once hazards have been identified and the risks assessed, appropriate control measures must be
put in place. Electrical safety generally depends on appropriate training, work planning, and
correct testing procedures and techniques.
The ways of controlling risks are ranked from the highest level of protection and reliability to the
lowest. This ranking is known as the hierarchy of risk control. You must work through this
hierarchy to choose the control that most effectively eliminates or minimises the risk in the
circumstances, so far as is reasonably practicable. This may involve a single control measure or a
combination of two or more different controls.

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3.3.1 Elimination
The most effect control measure is to remove the hazard or hazardous work practice. For example,
working de-energised rather than energised eliminates significant electrical risks. That is why the
World Health Safety Regulations prohibit energised electrical work subject to certain exceptions.
3.3.2 Substitution
Replacing a hazardous process or material with one that is less hazardous will reduce the hazard,
and hence the risk. For example, it may not be reasonably practicable to eliminate energised
electrical work altogether; however, even if it is necessary (for one of the legally permissible
reasons) to work on an energised electrical part, it may be possible to de-energise the surrounding
parts.
3.3.3 Isolation
Preventing workers from coming into contact with the source of the electrical hazard will reduce
the relevant risks.
3.3.4 Engineering controls
Use engineering control measures to minimise the risk, for example insulation, guarding and
installing residual current devices to prevent electric shock.
3.3.5 Administrative controls
Administrative controls involve the use of safe work practices to control the risk, for example the
provision of suitable and adequate training, establishing exclusion zones, use of permits and
warning signs.
3.3.6 Personal protective equipment (PPE)
PPE includes protective eyewear, insulated gloves, hard hats, aprons and breathing protection. The
PPE should be rated for the work to be done. If working on energised equipment, the PPE must be
able to protect the user from the maximum prospective energy available at the work site.
Administrative controls and PPE do nothing to change the hazard itself. They rely on people
behaving as expected and require a high level of supervision. Exclusive reliance on administrative

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controls and PPE must only occur where other measures are not reasonably practicable or as an
interim control while the preferred control measure is being implemented.
However, administrative controls such as procurement and personnel policies and procedures are
very important in relation to electrical risks, as they will help to ensure that electrical work is
carried out by a qualified electrician as required by law.
Review the control measures: You should check that your chosen control measure does not
introduce new hazards.

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Chapter 4
RISK CONTROLS – WORKING ON DE-ENERGISED
4.1 Working on De-energised Electrical Equipment
Electrical work (whether energised or de-energised) must only be carried out by appropriately
licensed or registered electrical workers. For more information about the applicable electrical
licensing or registration laws contact the local regulator in the relevant jurisdiction.
General principles – verification of de-energised electrical equipment
These provisions do not apply to work carried out by or on behalf of electricity supply authorities
on the electrical equipment, including line-associated equipment, controlled or operated by the
authority to generate, transform, transmit or supply electricity. This exemption does not extend to
the electricity generation sector.
A person conducting a business or undertaking carrying out electrical work must ensure that,
before electrical work is carried out on electrical equipment, the equipment is tested by a competent
person to determine whether or not it is energised.
The person conducting a business or undertaking must ensure that:
 each exposed part is treated as energised until it is isolated and determined not to be
energized.
 each high-voltage exposed part is earthed after being de-energised.
A person conducting a business or undertaking must ensure that electrical equipment that has been
de-energised to allow for electrical work to be carried out cannot be inadvertently re-energised.
The safe work procedure ‘TEST FOR ‘DEAD’ BEFORE YOU TOUCH’ must be applied at all
times. Even if the electricity supply is believed to have been isolated, it must be assumed that all
conductors and electrical components are energised until they have been proven de-energised.
Testing for ‘dead’ must be undertaken as appropriate for the duration of the electrical work. Testing
is undertaken prior to touching, taking into account all relevant factors including the nature of the
conductor, nature of the isolation, nature of work, if there has been a change or the area has been
left idle (unattended) for a period.

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The testing method (including the tester used) must be safe and effective. The electrical worker
carrying out the testing must understand testing procedures and be competent in the use of the
tester.
4.2 Safe Work Method Statements
A person conducting a business or undertaking must ensure that electrical work on energised
electrical equipment is carried out in accordance with a safe work method statement.
Safe work method statements are required in relation to prescribed ‘high risk construction work’,
in addition to energised electrical work.
4.3 Work on Cables (including Cutting Cables)
Where work is to be carried out on a cable, the cable should be de-energised. Cables must be
treated as energised and the procedures for working on energised electrical equipment followed
until positive tests can be made that prove the cable is de-energised. If the cable’s connections are
exposed the connections and attached live parts should be proved to be de-energised and identified
before work starts. Cutting cables presents particular risks. Both ends of the cable should be
checked for isolation prior to cutting. Schematic diagrams or ‘as built’ diagrams should be checked
carefully to establish secondary or metering circuits in multi-cored cables prior to cutting.
Additional precautions should be taken to ensure insulated or covered cables are de-energised,
whether the cables are low voltage, high voltage or control cables. For example, the action of
cutting a multi-core control cable is likely to create a risk if secondary current from a current
transformer is present. This risk may not be initially apparent; that is, the cable cutters may not be
damaged when the cable is cut. A high voltage may develop across the open-circuited secondary
winding causing an electric shock, arcing or a fault at a later stage.
4.4 Low Voltage Isolation and Access
Working de-energised on low voltage electrical equipment or circuits requires the electrical
equipment or circuits to be effectively isolated from all relevant sources of electricity supply. This
may be done using opening switches, removing fuses or links, opening circuit breakers or
removing circuit connections.
The standard steps in low voltage isolation are:

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Consulting with the person with management or control of the workplace and notifying any other
affected persons as appropriate.
4.4.1 Identifying the circuits requiring isolation
 Disconnecting active conductors from the relevant source(s), noting there may be multiple
sources and stand-by systems/generators/photovoltaic systems as well as auxiliary supplies
from other boards
 If a removable or rack out circuit breaker or combined fuse switch is used it should, if
reasonably practicable, be racked out or removed then locked open and danger tagged
Securing the isolation
 Locking the isolating switches where practicable or removing and tying back relevant
conductors to protect the persons carrying out the electrical work.
 Tagging the switching points where possible to provide general information to people at
the workplace.
 Testing to confirm the relevant circuits have been de-energised and any other relevant
conductors in the work area
 Re-testing as necessary, for example, if the person carrying out the work temporarily leaves
the immediate area, checks and tests must be carried out on their return to ensure that the
electrical equipment being worked on is still isolated to safeguard against inadvertent
reconnection by another person.
4.4.2 The effectiveness of isolation procedures relies on:
 Isolation points being readily available/accessible and being suitable for the type of
isolation (switching) being conducted.
 The necessary hardware.
 Having isolation procedures documented and accessible to electrical workers in the
workplace.
 The provision of instruction, information and training of electrical workers involved with
the electrical equipment.
 Appropriate supervision to ensure safe work procedures, including isolation procedures,
are followed.

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Safe isolation procedures (including the use of locks and tags) should be developed in consultation
with relevant workers. If the workers are represented by a health and safety representative, the
consultation must involve that representative.
4.4.3 Securing the isolation
A person conducting a business or undertaking must ensure that electrical equipment that has been
de-energised to allow electrical work to be carried out on it is not inadvertently re-energised while
the work is being carried out.
For work on low voltage electrical equipment or circuits, ensure that the correct point of isolation
is identified, an appropriate means of isolation is used and the supply cannot be inadvertently re-
energised while the work is carried out.
A fundamental principle is that the point of isolation should be under the control of the person who
is carrying out the work on the isolated conductors.
Tagging systems should also be used at the point(s) of isolation where possible for general
information.
The isolation should be secured by locking off and tagging the electrical equipment as follows.
Instruction, information, training and supervision
Appropriate instruction, information, training and supervision must be provided to ensure that
electrical equipment that has been de-energised to allow electrical work to be carried out is not
inadvertently re-energised. This includes appropriate instruction, information and training on
isolation proced..ures to everyone who may be affected at the workplace.
4.4.4 Locking off
Isolation points should be fitted with control mechanisms that prevent the electrical equipment
from being inadvertently re-energised. The control mechanism should require a deliberate action
to engage or disengage the device. It should be able to withstand conditions that could lead to the
isolation failing, for example vibration.
This may include switches with a built-in lock and lock-outs for switches, circuit breakers, fuses
and safety lock-out jaws (sometimes called ‘hasps’).

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All circuit breakers, switches and combined fuse switch units should be locked off to secure the
isolation where possible.
Alternative controls may include an additional component, for example a clip, screw, bolt or pin
that can be inserted to prevent a switch from being operated. These types of controls should be
used in conjunction with additional control measures, such as danger tags and permit systems.
If more than one person is working on the same de-energised electrical installation, individuals
should ensure their own personal lock is applied to the isolation point, otherwise the principles of
tagging apply (see below).
No-one should operate an isolator or knowingly use equipment where the isolator has a control
mechanism attached.
In situations where isolation points are accessible by other persons at the workplace ensure, so far
as is reasonably practicable, that the isolation method or system is not able to be inadvertently or
easily compromised.
4.4.5 Tagging systems
Danger tags involves using suitable warning or safety signs as well as locks or other controls to
secure the isolation. Where possible, a tag should be attached to normal locks at all points of
isolation used to de-energise electrical equipment from its electricity supply. A tag does not
perform the isolation function.
Danger tags are not required when using dedicated personal isolation locks.
Danger tags are used for the duration of the electrical work to warn persons at the workplace that;
 the electrical equipment is isolated or out of service.
 the electricity supply must not be switched back on or reconnected.
 reconnecting electricity may endanger the life of the electrical worker(s) working on the
equipment.

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4.4.6 The danger tag should:
 be durable and securely fixed to the isolator.
 clearly state the warning, including any warning about specific hazards relating to the
isolation (for example, multiple points of supply).
 be dated and signed by the worker or workers involved in carrying out the work or, where
appropriate, by the supervisor in charge of the workers.
 be attached in a prominent position on each isolation point (i.e. the point or one of many
points used to isolate electrical parts) or device.
 only be removed by the signatories to the tag. If unavailable and unable to return, measures
must be put in place to manage risks associated with removing the lock or tag (e.g. thorough
investigation to ensure all workers and others at the workplace are safe).
If the work is incomplete, for example at a change of shift, the last person removes their danger
tag or lock and replaces it with a warning tag e.g. out of service or caution. When work is resumed,
the person in charge of the work removes the warning tag (out of service or caution) and each
person then applies their danger tag and/or lock. When work is finally completed, each person
removes their danger tag and/or lock. Where a formal permit system is used, all reasonable steps
must be taken to ensure that the designated sign-on and tagging procedures are followed.
4.4.7 Out of service tags
Out of service or caution tags are used to identify electrical equipment that is not safe to use or fit
for purpose. The out of service or caution tag should:
 be durable and securely attached.
 clearly state the nature of the defect or reason why the electrical equipment is unsafe.
 be attached on a prominent position on each isolation point.
 only be removed by a competent person after fixing or rectifying the defect and making
the electrical equipment safe, or replacing with a danger tag in preparation to work on the
equipment.

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4.4.8 Restoring power
All reasonable steps must be taken to ensure that restoring electricity supply following isolation
does not pose risks to health and safety at the workplace. For example:
 appropriately terminating all conductors.
 carrying out appropriate testing on any new, altered or repaired electrical equipment, for
example tests for insulation resistance, earth continuity, polarity, correct connection and
function testing.
 removing safeguards, including temporary bonds and short-circuiting devices.
 notifying all workers working on the electrical equipment and other affected workers at the
workplace that electricity is to be restored.
 taking precautions as appropriate to ensure that other electrical equipment is not
inadvertently energised.
 carrying out a visual inspection to ensure that all tools, surplus material and waste has been
removed from the workplace.
When electricity is restored tests must be carried out to confirm that polarity is correct, actives are
switched .
4.4.9 Leaving unfinished work
If work is left unfinished, the workplace must be left in a safe state including, for example, by:
 terminating any exposed conductors.
 physically securing any exposed conductors or surrounding metal work.
 tagging, taping off the electrical equipment and the workplace area.
 informing affected persons at the workplace the work is not complete and advising of
potential hazards.
 taking any necessary precautions to ensure that electrical equipment cannot become
inadvertently re-energised.
 ensuring that the status of switchboards and electrical equipment are clearly and correctly
labelled

28. 28
 handing over adequate information to workers taking up the unfinished work to allow them
to continue the work safely.

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CHAPTER 5
RISK CONTROLS – ENERGISED ELECTRICAL WORK
5.1 Prohibition on Energised Electrical Work
A person conducting a business or undertaking carrying out electrical work must ensure the work
is not carried out on energised electrical equipment unless:
 it is necessary in the interests of health and safety that the electrical work is carried out
while the equipment is energised (e.g. it may be necessary for life-saving equipment to
remain energised and operating while electrical work is carried out on the equipment)
 it is necessary that the electrical equipment to be worked on is energised in order for the
work to be carried out properly.
 it is necessary for the purposes of testing to ensure the equipment is de-energised.
 there is no reasonable alternative means of carrying out the work
These requirements in relation to energised electrical work do not apply to work carried out by or
on behalf of electricity supply authorities on the electrical equipment, including line-associated
equipment, controlled or operated by the authority to transform, transmit or supply electricity.
These authorities may be covered by separate electrical safety requirements.
Energised electrical work is electrical work carried out in circumstances where the part of electrical
equipment being worked on is connected to electricity or ‘energised’.
Electrical work must not be carried out on electrical equipment while energised only because it is
merely more convenient for the electrical equipment to stay energised while the work is being
carried out.
Energised electrical work must not be carried out unless the safety risk to those persons directly
affected by a supply interruption is higher than the risk to the licensed or registered electrical
workers proposed to carry out the energised electrical work. Only in extremely rare circumstances
would it be possible to justify that it is not practicable to have a short break in supply. Most
electrical installations suffer no harm through unplanned interruptions of this kind to the network
supply. In some cases a short break may allow for the insertion (and removal) of insulated barriers.

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A Person conducting a business or undertaking requiring electrical work to be carried out may
provide operational reasons appearing to justify energised electrical work. Requiring electrical
work to be carried out while the equipment is energised when it could be avoided places an onerous
responsibility on the business or undertaking commissioning the work to minimize the risks.
Should an incident occur as a result of carrying out energised electrical work, the business or
undertaking commissioning the work is at risk of being found not to have provided a safe
workplace. This could contravene the primary duty of care under the WHS Act.
Energised electrical work is generally prohibited unless one or more of the exceptions under the
WHS Regulations applies and the work is carried out in accordance with the WHS Regulations.
5.2 Planning and Preparation
If electrical work is to be carried out on energised electrical equipment a person conducting a
business or undertaking must ensure before the work commences that:
 a risk assessment is conducted by a competent person in relation to the proposed work and
recorded
 the area where the electrical work is to be carried out is clear of obstructions so as to allow
for easy access and exit
 the point at which the electrical equipment can be disconnected or isolated from its
electricity supply is:
 clearly marked or labelled, and
 cleared of obstructions so as to allow for easy access and exit by the worker who is to carry
out the electrical work or any other competent person, and
 capable of being operated quickly
 the person authorises the electrical work after consulting with the person with management
or control of the workplace.
Requirements relating to the point of supply under the third dot point above do not apply if the
work is to be carried out on the supply side of the main switch on the main switchboard for the
equipment and the point at which the equipment can be disconnected from its electricity supply is
not reasonably accessible from the work location.

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5.3 Risk Assessments
A risk assessment involves considering what could happen if someone is exposed to a hazard and
the likelihood of it happening. Risks associated with electrical work may arise from:
 the properties of electricity, electricity is particularly hazardous because electrical currents
are not visible and do not have any smell or sound
 how and where the electrical work is carried out. Electrical work may be carried out in
difficult conditions, including in wet weather conditions, confined spaces and in
atmospheres that present a risk to health and safety from fire or explosion.
 the competence of the persons carrying out the electrical work.
If energised or ‘live’ electrical work is proposed to be carried out, a risk assessment must be
undertaken before the work starts and it must be carried out by a competent person and recorded.
5.4 Consultation Between Duty Holders
All persons conducting a business or undertaking at a workplace have a duty to manage electrical
risks at the workplace while electrical work is being carried out, not just those carrying out the
electrical work.
Electrical work will often be carried out at a place that is not under the management or control of
the person conducting the business or undertaking carrying out the electrical work. For example,
the place where work is carried out may be under the management or control of:
 if the place is a permanent workplace—the person conducting a business or undertaking
from that workplace
 if the place is a public place—the relevant local or state authority.
These persons will also have duties in relation to the health and safety of the electrical worker(s)
and other persons at the place where the electrical work is being carried out.
All duty holders must, so far as is reasonably practicable, consult, cooperate and coordinate
activities with each other to ensure compliance with their work health and safety duties. In addition
to the general duty to consult, the person conducting a business or undertaking carrying out the

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electrical work must ensure the electrical work is only authorised (among other things) after
consulting with the person with management or control of the workplace.
Consultation should ensure that all relevant persons are aware of any scheduled electrical work to
be carried out and also any relevant risks to health and safety arising from that work.
Arrangements should also be put in place to ensure, so far as is reasonably practicable, that all
persons at the place receive suitable and adequate information and instruction, for example about
the need to comply with warning or safety signs and stay out of any no go zones.
5.5 Residential Premises
Occupiers of residential premises (as a person at a workplace) must take reasonable care that their
acts or omissions do not adversely affect the health or safety of other persons, including that of
electrical workers at their premises.
Carrying out energised electrical work
A person conducting a business or undertaking must ensure that electrical work carried out on
energised electrical equipment is carried out:
 by a competent person who has tools, testing equipment and PPE that are suitable for the
work, have been properly tested and are maintained in good working order
 in accordance with a safe work method statement prepared for the work, and
 subject to the exception explained below—with a safety observer present who is
competent:
 to implement the control measures in an emergency
 to rescue the worker who is carrying out the work if necessary, and
 has been assessed in the previous 12 months as competent to rescue and resuscitate
a person.
The person must ensure, so far as is reasonably practicable, that the person who carries out the
electrical work uses the tools, testing equipment and PPE properly.

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Additionally:
 workers carrying out the electrical work must have or be provided with suitable and
adequate information, instruction and training in:
 planning and preparation requirements for the carrying out of energised electrical work

safe work procedures, particularly those documented in safe work method statements
 proper use of the relevant tools, testing equipment and PPE
 first aid facilities must be provided at the workplace and they must be readily accessible
 emergency contact numbers should be made available at the workplace
 fire fighting equipment that is suitable for electrical fires should be accessible
 the person with management or control of the workplace must be consulted before the
electrical work is authorised
 energised conductors should be insulated where necessary to prevent inadvertent contact
or flashovers
 unauthorised persons should be prevented from entering the work area, for example
through the use of barriers and signage.
Many of these requirements require consultation, cooperation and coordination between multiple
duty holders at the workplace.
Safe work method statements prepared for energised electrical work must describe consultation
arrangements with the person with management or control of the workplace, including any
authorisation procedures and position descriptions.
5.6 Safe Work Method Statements
Safe work method statements document a process for identifying and controlling health and safety
hazards and risks. They may also incorporate a risk assessment.
Safe work method statements must be developed in consultation with relevant workers. If the
workers are represented by a health and safety representative, the consultation must involve that
representative.

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Safe work method statements must:
 identify the electrical work.
 specify the hazards associated with that electrical work and risks associated with those
hazards
 describe the measures to be implemented to control the risks
 describe how the risk control measures are to be implemented, monitored and reviewed,
and may include the risk assessment prepared for the relevant work.
Safe work method statements must be written in a way that makes them readily understandable by
the workers who are to use them.
A copy must be readily accessible to any worker who is to carry out the electrical work covered
by the statement. Safe work method statements must be kept up-to-date. They must, for example,
be revised if a decision is made to change relevant safe work procedures at the workplace.
5.7 Risks Associated With Electrical Work Control Measures
Isolation and access
 Correctly isolating supply but not discharging residual energy e.g. a capacitive charge may
be present in power supplies, single-phase motors or high power factor fluorescent fittings.
 Insulation and equipment failing or partially breaking down.
 Earth connection failing to stop an electric shock in earthed conductive parts when step
and touch potentials exist.
 Carrying out the task causes a person, something a person may be handling or something
a person is in contact with to intrude into minimum safe approach distances.
 A power system conducting fault current or being subject to high inrush currents.
 Instructions or markings on the parts being inadequate, incorrect or both.
 Using equipment not designed for, or capable of, an operation e.g. opening a ‘no load –
bus tie’ under load conditions or relying on an open circuit breaker as an isolation point.
 Another person energising circuits while a worker is working on them, or a vehicle hitting
a pole.

35. 35
 Natural elements (i.e. lightning or wind) causing static charges, overhead mains to clash or
a high-voltage circuit to fall onto a low-voltage circuit.
 The inter-core capacitive effects of long multi-phase cables.
 Changes to wiring not being reflected in drawings i.e. the drawings are not ‘as built’ e.g. a
live control or supervision circuit being present though the drawing indicates otherwise.
 If there has been an error in wiring, opening the isolator may not de-energise the
switchboard e.g. if incorrect connection (incorrect polarity) occurred in the service to an
installation, opening the main switch will open circuit the neutral rather than the active.
 Intentionally disabling an interlock to perform a task e.g. opening the shutter of a ‘rackable’
circuit breaker test to prove de-energised in the orifice.
 Inadvertently disabling an interlock while performing a task e.g. in a switchboard with an
integrated circuit breaker, isolator and earth switch, the operator accidentally moving the
isolator into the earthed position.
 Poor direction and insufficient knowledge e.g. a worker is instructed to apply a set of earths
and short circuits at a Ring Main Unit (RMU). The worker correctly observes the isolator
is open, however they assume the earth switch can be closed because the isolator is open.
As most RMUs are configured so the earth switch earths the cable, not the busbar, it is
possible the worker would be earthing and short-circuiting a live circuit.
 When applying a set of portable earths and short-circuits, accidental or inadvertent contact
is made with live parts. If this occurs, the worker is using a device that is conducting fault
current.
 The threshold value (lowest level of indication or reading) of a test device causing a
misleading interpretation of a test to prove de-energised. Depending on the device used, an
indication that parts are not energised in a high-voltage situation does not mean that low-
voltage and direct current voltages are absent.
 Application of earthing and short-circuiting devices that depend on a conductive path
through a fuse or circuit breaker that is not fit for purpose.
 Ineffective connection to the general mass of the earth e.g. the electrode, grid or temporary
electrode that the earth and short circuits relies upon in a situation where a single phase
becomes energised.

36. 36
 Application of the short circuit portion of portable earthing devices prior to the earth tail
being connected to the earth.
 Arcing and splattering associated with the application of earths and short circuits, causing
a risk. The arcing or splattering may result from using the device in situations that range
from energised conductors to residual energy such as capacitance. If the parts are energised,
the worker can draw the arc from one phase to the other, causing a phase-to-phase fault.
 A potential electric shock path existing once the earth tail is connected to earth. A worker
may touch another live part and the earthed connector at the same time, for example in a
Common Multiple Earthed Neutral (CMEN) area, even when working on high-voltage,
contact between the earthed connector and a low-voltage phase can cause an electric shock.
Working near sources of arcing, explosion or fires, Arcs, explosions and electrical faults can cause
burns. Workers should be protected from the effects of burns. Examples include: materials
providing a conductive path between sources of potential, for example uninsulated tools falling
across busbars.
 abnormal conditions on circuits such as:
 lightning striking mains
 circuits of different voltages touching each other e.g. high-voltage contacting low-voltage
circuits
 high voltage in the secondary circuit of a current transformer if an open circuit occurs when
current is flowing in the primary circuit.
 abnormally high voltages when synchronising different supplies. For example, if the
waveforms are 180° out of phase, twice the peak-to-peak voltage may be imposed
voltage multiplication effects, including:
 ferro-resonance where the capacitive and inductive components of underground cables and
transformers can significantly increase voltages when single-phasing occurs.
 re-strike can occur if capacitors are energised, de-energised and re-energised in rapid
succession.

37. 37
 leakage or electrical discharge causing insulation to be compromised, for example a
combination of a build-up of contaminants on insulators, wet weather or tracking through
air voids in pitch filled insulating chambers
 failure of insulating mediums.
5.8 Working in Unsafe Atmospheres
After faults and fires, often in emergencies, electrical workers may be exposed to unsafe
atmospheres. Toxic gases and lack of oxygen can cause illness and death. General workplace
health and safety risk control measures should be used in these situations.
The method of extinguishing fires should be addressed. Typically, carbon dioxide or powder type
devices are used against electrical fires. Extinguishers including water, foam and wet chemical
should not be used as they significantly increase the risk of electric shock.
Modifying or repairing existing low-voltage electrical installations
 Electrical drawings/tables not reflecting ‘as installed’ installations.
 More than one source of supply or energised circuit may be available on the premises or at
the equipment.
 The supply becoming energised during the work.
 Automatic starting of machinery after supply is restored.
 Managing metallic shavings ingress into conductive parts of equipment.
 A conductor considered to be de-energised was found to be energised.
 Old installations (where several modifications may have been made, circuits have not been
identified, or the insulation has deteriorated).
 Voltages on disconnected conductors, particularly neutrals.
 Installations where the MEN system is used, the rise in the earth potential due to a high
impedance return path to the distribution neutral.
 Lack of information about isolation, sources of supply or the location of electrical
conductors.
 Lack of clear safe access to locate electric cables (other hazards may be present such as
exposed conductors).

38. 38
 Damage to conductors in metallic conduits where earthing continuity of the conduit has
not been maintained.
 Equipment located in hazardous areas, which includes bolt-on or screw-on covers, can be
dangerous if opened without obtaining specialist advice.
 Working alone on energised equipment.
 Drilling into switchboards/electrical enclosures.
 Contact with cables in walls, floors or roof spaces.
 Contact with cables during excavation work or cutting/drilling concrete.
 Exposure to asbestos material/switchboards.
 Variable frequency devices.
 Multiple circuits located within the one conduit.
 Use of conductive/flammable cleaning solvents creating an explosive atmosphere.
5.9 Testing and Fault Finding Low-Voltage Equipment and Installations
Risks arise as it is difficult to find faults or malfunctions in electrical equipment when the circuits
are not energised or when the equipment is not operating, especially if feedback circuits or sensors
are involved. Risks can include:
 electrical drawings/tables not reflecting ‘as installed’ installations
 exposed energised terminals or conductors
 terminals or conductors being energised under different conditions of operation of the
equipment
 loose or disconnected test leads or wiring becoming energised
 test equipment and leads bringing electrical hazards closer to the worker
 test equipment inappropriate for the task (particularly test probes)
 inadequate test points
 inadvertent attempts to start machinery by other persons
 incorrect or poorly maintained testing instruments
 inadequate knowledge of equipment or causes of faults
 lack of information about circuits or equipment

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 equipment located in hazardous areas, which includes bolt-on or screw-on covers, can be
dangerous if opened without obtaining specialist advice
 testing or fault finding alone on energised equipment
 testing or fault finding in cramped or restricted work situations
 rotating or moving machinery (crush hazards)
 overriding of interlocks or forcing of control equipment
 re-setting of protective devices in energised switchboards
 electrical installations where unauthorised electrical work has been undertaken.
High fault currents – working, testing or fault finding energised
When working, testing or fault finding on energised electrical equipment, a fault current of up to
20 times the rated current of the supply transformer can flow for short duration during fault
conditions.
Arcs can have the energy to cause an explosion and/or melt metallic switchboard cubicles and
equipment. Arcs may cause severe burns to the skin and flash burns to the face and eyes. Inhaled
hot gases and molten particles can cause serious internal burns to the throat and lungs. Injury can
also occur through the impact from flying debris and dislodged components. Circuit protection
devices may not operate in such circumstances. Testing, fault finding or working on or near low
voltage equipment
 Voltages between phases and between phases and neutral.
 Voltages between phases and earth.
 Voltages across open switch contacts, for example voltage across a light switch on an
incandescent lighting circuit or the voltage across a bus tie where one side is de-energised
 Voltages on disconnected conductors (particularly neutrals).
 Voltages from sources near the work being performs harmonics, for example 3rd harmonic
150 Hz in neutrals and earths where there is a large fluorescent light load and switch mode
power supplies

40. 40
5.10 Preventative Actions Checklist
INITIAL ASSESSMENT
Yes No
Can the work be undertaken while the electrical equipment is
de-energised?
If Yes, proceed to Part 2. If No, is it:
 necessary in the interests of health and safety that the
electrical
work is carried out on the equipment while the equipment
is energised?
OR
 necessary that the electrical equipment to be worked on is
energised in order for the work to be carried out properly?
OR
 are there no reasonable alternative means of carrying
out the work?
If your answer to any of these is ‘yes’ proceed to Part 3 after
considering whether part of the installation or equipment may
be de-energised while the work is carried out.
If you cannot answer ‘yes’ to any of these proceed to Part 2—you
must work de-energised.
WORKED ON DE-ENERGISE Yes No
Do you have approved test instruments suitable for the task?
Have you checked that the test instruments are functioning correctly?
Have you isolated the supply e.g. by switching off?
Have you taken precautions to ensure that the supply remains
isolated

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Have you taken precautions to ensure that the supply remains
isolated by locking off and/or tagging, or disconnecting the load side
of the isolator and tying back disconnected conductors?
Have you conclusively tested that the equipment is
de-energised?
You must carry out the electrical work in accordance with
any safe work method statement that must be prepared
for the work.
PART 3: WORK ON OR NEAR ENERGISED EQUIPMENT Yes No
Has a risk assessment been conducted by a competent person which
identifies all electrical hazards and non-electrical hazards, both
actual
and potential?
Is the work area clear of obstructions to allow for easy access?
Is the isolation point clearly marked or labelled and capable of being
operated quickly?
Has the person with management or control of the workplace been
consulted about the proposed electrical work?
Do you have a safe work method statement for the task
at hand? This should state the control measures required
to eliminate or minimise the risks
Are you trained, competent and confident in applying the particular
procedures or techniques that are required for
the task?
Have you checked to ensure that your tools and accessories are
insulated and have been inspected and maintained to ensure they are
serviceable?
Is your test equipment appropriate to the task and functioning
correctly?

42. 42
Are you wearing the appropriate clothing and associated PPE for the
task e.g. safety helmet and boots, insulating gloves?
Do you have the appropriate insulating mats and sheeting?
Is a safety observer present?
Note: a safety observer is not required for electrical work if it only
involves testing and the risk assessment shows that there is no
serious
risk associated with the work.
Are the necessary first aid facilities provided and accessible and are
unauthorised persons prevented from entering the work area?
REMEMBER:
 Do the work very carefully.
 Follow the safe work procedures.
 Assume all exposure conductors are energised.
 Be aware of the voltage to the earth of all exposed
conductors.
Yes No
Have the installations/circuits/equipment been restored to
a safe and operable condition?
Have all tags and locking-off devices been removed?
5.11 Components Control Measures
5.11.1 Fuse
Normally, a fuse is a copper wiring with a set current fusion value. If the current exceeds the set
fusion value, the fuse will blow and the current is cut-off, thus preventing overloading. A fuse
interrupts excessive current (blows) so that further damage by overheating or fire is prevented.
Wiring regulations often define a maximum fuse current rating for particular circuits. Overcurrent
protection devices are essential in electrical systems to limit threats to human life and property
damage. The time and current operating characteristics of fuses are chosen to provide adequate
protection without needless interruption. Slow blow fuses are designed to allow harmless short

43. 43
term currents over their rating while still interrupting a sustained overload. Fuses are manufactured
in a wide range of current and voltage ratings to protect wiring systems and electrical equipment.
Self-resetting fuses automatically restore the circuit after the overload has cleared, and are useful
in environments where a human replacing a blown fuse would be difficult or impossible, for
example in aerospace or nuclear applications.
Figure 2: a fuse
5.11.2 Circuit Breakers
All newer homes are protected by circuit breakers. Unlike a fuse that must be replaced when it
blows, a circuit breaker that has “tripped” can be mechanically reset to resume operations once the
problem has been resolved. Each circuit breaker contains a permanent metal strip that heats up and
bends when electricity moves through it. If a circuit shorts out or becomes overloaded, the metal
strip bends enough to “trip,” flipping a switch that immediately shuts off power to the circuit.
Circuit breakers also protect branch circuits, which can be sized for 120-volts or 240-volts.
Figure 3: Circuit Breaker

44. 44
5.11.3 Arc Fault Circuit Interrupters (AFCIS)
AFCIs are new protective devices that replace standard circuit breakers in the electric service
panel. AFCIs provide enhanced protection against additional fire hazards known as arc faults. An
arc fault is a dangerous electrical problem caused by damaged, overheated, or stressed electrical
wiring or devices. Without AFCIs, arc faults may be hidden from plain view until it is too late.
Figure 4 : Arc Fault Circuit Interrupters
5.11.4 Ground Fault Circuit Interrupters (GFCIs)
Since the 1970s, Ground Fault Circuit Interrupters (GFCIs) have saved thousands of lives and have
helped cut the number of home electrocutions in half. GFCIs are electrical safety devices that trip
electrical circuits when they detect ground faults or leakage currents. A person who becomes part
of a path for leakage current will be severely shocked or electrocuted. These outlets prevent deadly
shock by quickly shutting off power to the circuit if the electricity flowing into the circuit differs
by even a slight amount from that returning.
A GFCI should be used in any indoor or outdoor area where water may come into contact with
electrical products. The 2008 edition of the National Electrical Code currently requires that GFCIs
be used in all kitchens, bathrooms, garages, and outdoors.
GFCIs should be tested once a month to confirm that they are working properly.

45. 45
Figure 5: Ground Fault Circuit Interrupters
The night light should go out when the test button is pushed. If the light does not go out, then the
GFCI may have been improperly wired or damaged and does not offer shock protection. In this
case, contact a licensed electrician to check the GFCI and correct the problem.
5.11.5 Earth Leakage Circuit Breaker
Current leakage protection is also called Residual Current Protection (RCD) or Earthing Fault
Current Protection. Earth leakage circuit breakers monitor the operation of the "neutral" or "live"
wires in the electrical circuit. During an imbalance in the electrical circuit, or when not all the
current flows to the electrical appliance through the "live" wire and returns through the "neutral"
wire, part of the current flows away (leaks) into other sources. The earth leakage circuit breaker
will immediately detect such an imbalance and cut-off the electrical source in 0.4 seconds. Rating
of the tripping current shall not exceed 30mA.
Figure 6 : Earth Leakage Circuit Breaker

46. 46
5.11.6 Insulation
One way to safeguard individuals from electrically energized wires and parts is through insulation.
An insulator is any material with high resistance to electric current.
Insulators-such as glass, mica, rubber, and plastic-are put on conductors to prevent shock, fires,
and short circuits. Before employees prepare to work with electric equipment, it is always a good
idea for them to check the insulation before making a connection to a power source to be sure there
are no exposed wires. The insulation of flexible cords, such as extension cords, is particularly
vulnerable to damage.
5.11.7 Extra-low voltage
Using electrical tools with an extra-low voltage of less than 50 V may minimise injury in case of
electric shock. When extra-low voltage is used, an earthing connection may not be required.
5.11.8 Guarding
Live parts of electric equipment operating at 50 volts or more must be guarded against accidental
contact. Guarding of live parts may be accomplished by:
 location in a room, vault, or similar enclosure accessible only to qualified persons;
 use of permanent, substantial partitions or screens to exclude unqualified persons;
 location on a suitable balcony, gallery, or platform elevated and arranged to exclude
unqualified persons; or
 elevation of 8 feet (2.44 meters) or more above the floor.
Entrances to rooms and other guarded locations containing exposed live parts must be marked with
conspicuous warning signs forbidding unqualified persons to enter. Indoor electric wiring more
than 600 volts and that is open to unqualified persons must be made with metal-enclosed
equipment or enclosed in a vault or area controlled by a lock. In addition, equipment must be
marked with appropriate caution signs.

47. 47
Figure 7: Guarding System
5.12 Safe Work Practices
Employees and others working with electric equipment need to use safe work practices. These
include: de-energizing electric equipment before inspecting or making repairs, using electric tools
that are in good repair, using good judgment when working near energized lines, and using
appropriate protective equipment.
5.13 Training
To ensure that they use safe work practices, employees must be aware of the electrical hazards to
which they will be exposed. Employees must be trained in safety-related work practices as well as
any other procedures necessary for safety from electrical hazards.
De-energizing Electrical Equipment. The accidental or unexpected sudden starting of electrical
equipment can cause severe injury or death. Before ANY inspections or repairs are made -- even
on the so-called low-voltage circuits-the current must be turned off at the switch box and the switch
padlocked in the OFF position. At the same time, the switch or controls of the machine or other
equipment being locked out of service must be securely tagged to show which equipment or
circuits are being worked on.
Maintenance employees should be qualified electricians who have been well instructed in lockout
procedures. No two locks should be alike; each key should fit only one lock, and only one key
should be issued to each maintenance employee. If more than one employee is repairing a piece of
equipment, each should lock out the switch with his or her own lock and never permit anyone else

48. 48
to remove it. The maintenance worker should at all times be certain that he or she is not exposing
other employees to danger.
5.14 Overhead Lines
If work is to be performed near overhead power lines, the lines must be de-energized and grounded
by the owner or operator of the lines, or other protective measures must be provided before work
is started. Protective measures (such as guarding or insulating the lines) must be designed to
prevent employees from contacting the lines.
Unqualified employees and mechanical equipment must stay at least 10 feet (3.05 meters) away
from overhead power lines. If the voltage is more than 50,000 volts, the clearance must be
increased by 4 inches (10 centimeters) for each additional 10,000 volts.
When mechanical equipment is being operated near overhead lines, employees standing on the
ground may not contact the equipment unless it is located so that the required clearance cannot be
violated even at the maximum reach of the equipment.
Protective Equipment. Employees whose occupations require them to work directly with
electricity must use the personal protective equipment required for the jobs they perform. This
equipment may consist of rubber insulating gloves, hoods, sleeves, matting, blankets, line hose,
and industrial protective helmets.
Tools. To maximize his or her own safety, an employee should always use tools that work properly.
Tools must be inspected before use, and those found questionable, removed from service and
properly tagged. Tools and other equipment should be regularly maintained. Inadequate
maintenance can cause equipment to deteriorate, resulting in an unsafe condition.
Tools that are used by employees to handle energized conductors must be designed and constructed
to withstand the voltages and stresses to which they are exposed.
Good Judgment. Perhaps the single most successful defense against electrical accidents is the
continuous exercising of good judgment or common sense. All employees should be thoroughly
familiar with the safety procedures for their particular jobs. When work is performed on electrical
equipment, for example, some basic procedures are:
1. Have the equipment de-energized.

49. 49
2. Ensure that the equipment remains de-energized by using some type of lockout and tag
procedure.
3. Use insulating protective equipment.
4. Keep a safe distance from energized parts.

50. 50
CHAPTER 6
EARTHING
6.1 Definition of Earthing
In electrical engineering, ground or earth can refer to the reference point in an electrical circuit
from which voltages are measured, a common return path for electric current, or a direct physical
connection to the Earth. A typical earthing electrode consisting of a conductive rod driven into the
ground.
6.2 Reasons for Earthing
Electrical circuits may be connected to ground (earth) for several reasons. In mains powered
equipment, exposed metal parts are connected to ground to prevent user contact with dangerous
voltage if electrical insulation fails. Connections to ground limit the build-up of static electricity
when handling flammable products or electrostatic-sensitive devices. In some telegraph and power
transmission circuits, the earth itself can be used as one conductor of the circuit, saving the cost of
installing a separate return conductor.
For measurement purposes, the Earth serves as a (reasonably) constant potential reference against
which other potentials can be measured. An electrical ground system should have an appropriate
current-carrying capability to serve as an adequate zero-voltage reference level. In electronic
circuit theory, a "ground" is usually idealized as an infinite source or sink for charge, which can
absorb an unlimited amount of current without changing its potential. Where a real ground
connection has a significant resistance, the approximation of zero potential is no longer valid. Stray
voltages or earth potential rise effects will occur, which may create noise in signals or if large
enough will produce an electric shock hazard.
6.3 Earthing system
Electrical power distribution systems are often connected to ground to limit the voltage that can
appear on distribution circuits. A distribution system insulated from ground may attain a high
potential due to transient voltages caused by arcing, static electricity, or accidental contact with
higher potential circuits. A ground connection of the system dissipates such potentials and limits
the rise in voltage of the grounded system.

51. 51
Figure 8: Earthing system
Equipment earthing conductors provide an electrical connection between non-current-carrying
metallic parts of equipment and the earth. According to the U.S. National Electrical Code (NEC),
the reason for doing this is to limit the voltage imposed by lightning, line surges, and contact with
higher voltage lines. The equipment earthing conductor is usually also used as the equipment
bonding conductor.
6.4 How Earthing System Work
Equipment bonding conductors provide a low impedance path between non-current-carrying
metallic parts of equipment and one of the conductors of that electrical system's source, so that if
a part becomes energized for any reason, such as a frayed or damaged conductor, a short circuit
will occur and operate a circuit breaker or fuse to disconnect the faulted circuit. Note that the earth
itself has no role in this fault-clearing process since current must return to its source, not the earth
as is sometimes believed (Kirchhoff's circuit laws). By bonding (interconnecting) all exposed non-
current carrying metal objects together, they should remain near the same potential thus reducing
the chance of a shock. This is especially important in bathrooms where one may be in contact with
several different metallic systems such as supply and drain pipes and appliance frames. The
equipment bonding conductor is usually also used as the equipment earthing conductor.
Permanently installed electrical equipment usually also has permanently connected grounding
conductors. Portable electrical devices with metal cases may have them connected to earth ground
by a pin in the interconnecting plug (Domestic AC power plugs and sockets). The size of power
ground conductors is usually regulated by local or national wiring regulations.

52. 52
6.5 Earthing of a Power Distribution System
Distribution power systems may be solidly grounded, with one circuit conductor directly
connected to an earth grounding electrode system. Alternatively, some amount of electrical
impedance may be connected between the distribution system and ground, to limit the current that
can flow to earth. The impedance may be a resistor, or an inductor (coil). In a high-impedance
grounded system, the fault current is limited to a few amperes (exact values depend on the voltage
class of the system); a low-impedance grounded system will permit several hundred amperes to
flow on a fault. A large solidly-grounded distribution system may have thousands of amperes of
ground fault current.
In a polyphase, AC system, an artificial neutral grounding system may be used. Although no phase
conductor is directly connected to ground, a specially constructed transformer (a "zig zag"
transformer) blocks the power frequency current from flowing to earth, but allows any leakage or
transient current to flow to ground.
6.6 Effect of Ungrounded Systems
Where the danger of electric shock is high, special ungrounded power systems may be used to
minimize possible leakage current to ground. Examples of such installations include patient care
areas in hospitals, where medical equipment is directly connected to a patient and must not permit
any power-line current to pass into the patient's body. Medical systems include monitoring devices
to warn of any increase of leakage current. On wet construction sites or in shipyards, isolation
transformers may be provided so that a fault in a power tool or its cable does not expose users to
shock hazard.
Circuits used to feed sensitive audio/video production equipment or measurement instruments may
be fed from an isolated ungrounded technical power system to limit the injection of noise from the
power system.
6.7 Lightning Protection Systems
Lightning protection systems are designed to mitigate the effects of lightning through connection
to extensive grounding systems that provide a large surface area connection to earth. The large
area is required to dissipate the high current of a lightning strike without damaging the system

53. 53
conductors by excess heat. Since lightning strikes are pulses of energy with very high frequency
components, grounding systems for lighting protection tend to use short straight runs of conductors
to reduce the self-inductance and skin effect. Busbars are used for ground conductors in high-
current circuits.
6.8 Electrical Bonding
Strictly speaking, the terms grounding or earthing are meant to refer to an electrical connection to
ground/earth. Bonding is the practice of intentionally electrically connecting metallic items not
designed to carry electricity. This brings all the bonded items to the same electrical potential as a
protection from electrical shock. The bonded items can then be connected to ground to bring them
to earth potential.
6.9 Earthing Mat
In an electrical substation a ground (earth) mat is a mesh of conductive material installed at places
where a person would stand to operate a switch or other apparatus; it is bonded to the local
supporting metal structure and to the handle of the switchgear, so that the operator will not be
exposed to a high differential voltage due to a fault in the substation. In the vicinity of electrostatic
sensitive devices, a ground mat is used to ground static electricity generated by people and moving
equipment.
6.10 Isolation (Disconnector)
It means physically disconnected from all possible sources of supply. Generally every AC power
line transformer acts as an isolation transformer, and every step up or down has the potential to
form an isolated circuit. However, this isolation would prevent failed devices from blowing fuses
when shorted to their ground conductor. The isolation that could be created by each transformer is
defeated by always having one leg of the transformers grounded, on both sides of the input and
output transformer coils. Power lines also typically ground one specific wire at every pole, to
ensure current equalization from pole to pole if a short to ground is occurring.
Electrical engineering, a disconnector, disconnect switch or isolator switch is used to ensure that
an electrical circuit is completely de-energised for service or maintenance. Such switches are often
found in electrical distribution and industrial applications, where machinery must have its source

54. 54
of driving power removed for adjustment or repair. High-voltage isolation switches are used in
electrical substations to allow isolation of apparatus such as circuit breakers, transformers, and
transmission lines, for maintenance. The disconnector is usually not intended for normal control
of the circuit, but only for safety isolation. Disconnector can be operated either manually or
automatically (motorized disconnector).
Unlike load break switches and circuit breakers, disconnectors lack a mechanism for suppression
of electric arc, which occurs when conductors carrying high currents are electrically interrupted.
Thus, they are off-load devices, intended to be opened only after current has been interrupted by
some other control device. Safety regulations of the utility must prevent any attempt to open the
disconnector while it supplies a circuit. Standards in some countries for safety may require either
local motor isolators or lockable overloads (which can be padlocked).
Disconnectors have provisions for a padlock so that inadvertent operation is not possible (lockout-
tagout). In high-voltage or complex systems, these padlocks may be part of a trapped-key interlock
system to ensure proper sequence of operation. In some designs, the isolator switch has the
additional ability to earth the isolated circuit thereby providing additional safety. Such an
arrangement would apply to circuits which inter-connect power distribution systems where both
ends of the circuit need to be isolated.
Figure 9 : Disconnector

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CHAPTER 7
HOUSE KEEPING
Figure 10 : House Keeping
7.1 Concept of House Keeping
Workmen are frequently injured, by stumbling, stepping on, or bumping into tools, material and
other objects left lying around, or by objects falling from above. To ensure good housekeeping
following precautions should be observed:
 Walks, stairways, fire escapes and all other passageways shall be kept clear of all
obstructions.
 Tools and materials should not be placed where they may cause tripping or stumbling
hazards or where they may fall and strike anyone below.
 Puddles of oil and water create slipping hazards and should be cleaned up promptly.
 Nails in boards, such as those removed from scaffolds, forms and packing boxes, constitute
hazards and should be removed. The boards should be carefully stacked or stored.
 Dirty and oily waste rags should be deposited in approved containers and disposed off as
soon as practicable to avoid fire hazard.

56. 56
 Broken light bulbs, glass metal and scrap and other sharp objects should be dumped in
places or containers provided specially for them.
 Discarded fluorescent and other gas filled tubes shall be disposed off safely.
 Places where persons work or pass in emergencies, shall be provided during time of use
with adequate lighting (natural / artificial / or both) for operations or special type of work
performed.
 General lighting shall be of a uniform level widely distributed.
 In big installations / offices emergency lighting shall be provided.
 Adequate ventilation shall be provided in work places by natural / artificial means.
7.2 Electrical Safety for Buildings
All electrical installations for Bureau owned, operated, or leased buildings including, but not
limited to, gage stations, marina docks, cabins, and shelters must:
 Be installed, repaired, and/or maintained by a licensed electrician.
 Have a disconnect that will allow the electricity to be de-energized and that can be locked
out.
 Be grounded or employees protected by ground-fault circuit interrupters (GFCIs). GFCIs
will not protect equipment.
 If subjected to wet conditions, be protected from water; employees must be protected by
ground-fault circuit interrupters.
 Have an arc lash hazard assessment and be labeled with the required precautions for live
electrical work.
7.3 Equipment
Normal use of electrical equipment causes wear and tear that results in insulation breaks, short
circuits, and exposed wires. If there is no ground-fault protection, it can cause a ground fault that
sends current through an employee’s body.
 Use ground-fault circuit interrupters (GFCIs) on all 120-volt, single-phase, 15- and 20-
ampere receptacles on all field equipment.
 Use double-insulated tools and equipment, distinctively marked.

57. 57
 Visually inspect all electrical equipment before use. Remove from service any equipment
with frayed cords, missing ground prongs, cracked tool casings, or other hazards.
 Use only equipment that is listed and labeled by a nationally recognized testing laboratory
for the intended use.
7.4 Extension Cords
Normal wear on cords can loosen or expose wires. Cords that are not 3-wire type, not designed for
hard usage, or that have been modified increase your risk of contacting electrical current.
 Do not modify cords or use them incorrectly.
 Use factory-assembled cord sets and only extension cords that are 3-wire type.
 Use only cords, connection devices, and fittings that are equipped with strain relief.
 Remove cords from receptacles by pulling on the plugs, not the cords.
 Use of extension cords (flexible cords) for permanent installation of appliances and
equipment is prohibited.
 Replace extension cords that are damaged so individual wires can be seen through the
protective sheathing. Do not repair.
 If an extension cord insulation is cut, it is better to cut the damaged section out and add a
new plug than to try and repair the insulation. Never repair insulation using electrical tape,
which does not have equivalent insulation and it is easily damaged.
7.5 Power Lines
Overhead and buried power lines are especially hazardous because they carry extremely high
voltage. Fatal electrocution is the main risk, but burns and falls are also hazards.
 Look for overhead power lines and buried power line indicators.
 Stay at least 10 feet away from overhead power lines and assume they are energized.
 Use nonconductive wood or fiberglass ladders when working near power lines.
 De-energize and ground lines when working near them. Call the electrical utility to do
this.
 Call the electrical utility for work that it is responsible for, such as tree trimming.

58. 58
7.6 Safety do’s and don’t
s/n Do’s Don’t
1 Before replacing a lamp or handling a
fan, make sure that the supply is
switched off.
Do not connect single pole switch or fuse in
a neutral circuit, but always connect in the
live or phase wire.
2. Place Safety Tagging or other warning
boards on main switch before
commencing work
Do not close any switch, unless you are
familiar with the circuit which it controls
and know the reason for its
being open
3. Before working on any circuit or
apparatus,make sure that the
controlling switches are open and
locked.
Do not touch or tamper with any electrical
gear or conductor, unless you have made
sure that it is dead
and earthed. High voltage apparatus may
give leakage shock or flash over even
without touching
4. Always treat circuit as live until you
have proved them to be dead, the
insulation of the conductor may be
defective.
Do not work on live circuit without the
orders of the authorized person. Make
certain that all safety precautions have been
taken
5. Cultivate the habit or turning your
face away whenever the flash or an arc
may
occur.
Do not disconnect earthing connection or
render it ineffective of the safety gadgets
installed on mains and apparatus.
6. Guard against arcs as well as high
voltage; remember that burns from arc
are very severe.
Do not tamper with the meter board and cut-
outs,
unless you are authorized to do so
7. See that all the splices and
connections are securely made.
Do not expose your eyes toan electrical arc.
Painful

59. 59
. injury may result even with short exposure.
8. Use extreme care when breaking an
inductive circuit as dangerously high
voltage is likely to result.
Do not close or open a switch slowly or
hesitatingly. Do it quickly and positively
9. Thoroughly discharge to earth all
cables before working on cores.
Do not place any part of yourbody in circuit
either to ground or across the terminal when
making a connection or doing operation
10. Test rubber gloves periodically. Do not touch an electrical circuit when your
hands are wet, bleeding from a cut or have
an abrasion
11 Place rubber mats in front of
electrical switchboard
Do not work on energized circuit without
taking extra precautions, such as the use of
rubber gloves. Do not use metal case flash
light around apparatus which is energized.
12 Preach and practice safety at all the
time. Good work can be spoiled by an
accident.
Do not wear loose clothing, metal watch
straps, bangles or finger rings while
working on appliances. Do not hang clothes
and such other things on electric fittings. Do
not touch the circuit with bare fingers or
hand or other makeshift devices to
determine whether or not it is live.
13 Work deliberately and carefully.
Haste causes many accidents. Be sure
of what you are doing.
Do not work on pole or any elevated
position if there is a live part on it, without
the safety belt and rubber gloves and unless

60. 60
the authorized person stand on the ground
nearby to direct operation and give warning.
14 Always obey the safety instructions
given by the person in-charge.
Do not use a ladder without a lashing rope,
otherwise the ladder should be held firmly
by another person. Do not remove Safety
Tags or other signs or interface with safety
barriers or go beyond them
15 Always report immediately to the
person in-charge or to any other
proper authority of any dangerous
condition or a practice, which you
may observe.
Do not bring naked light near battery.
Smoking in the battery room is prohibited.
Do not allow visitors and un-authorized
person to touch or handle electrical
apparatus or come within the danger zone of
high voltage apparatus.
16 Ensure that all portable appliances are
provided with 3 pin plug and socket
connections. Also the metal work of
the apparatus is effectively earthed.
Do not use a lamp in a metal holder fixed to
the end of a loose flexible wire as a portable
hand lamp. Do not disconnect a plug by
pulling the flexible cable
or when the switch is on

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CHAPTER 8
PERMIT TO WORK
8.1 Definition of Permit to Work
The Permit-to Work procedure provides a formal control system aimed at the prevention of
accidents and damage to property where foreseeable hazardous work is carried out.
The Permit-to-Work consists of documents which:
 Details the work to be done.
 Details the precautions to take.
 Identifies all the foreseeable hazards.
 States the control measures to be implemented.
 Cancellation.
 List other permits in operation.
Permits themselves do not make a job free from risks, they rely upon effective control and co-
ordination in order that hazards are identified and risks are suitably assessed.
The Health and Safety Executive identify the following requirements of a Permit-to-Work;
 Type of Permit – i.e. Electrical, Asbestos etc.
 Unique Permit Number.
 Location of work.
 Details of the work to be carried out.
 Identification of hazards.
 Precautions required.
 Personal Protective Equipment required.
 Authorisation to commence work.
 Any extension of permit time.
 Handback.
 Cancellation.

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8.2 Conditions for a Permit
The company will expect Permits-to-Work to be issued to ether high and low voltage work in the
following situations;
A. Working in confined spaces.
B. Work in control and switching.
C. cable jointing work
D. Working with Asbestos
E. working on overhead lines.
F. Work on underground cable.
G. work on high voltage electrical equipment.
8.3 Competent Persons
The use of Competent Persons is a prime requirement of the Permit-to Work system. Although
Competency has never been defined in either case or statute law, the Health and Safety at Work
Regulations define a person as being Competent when that person;
“Has sufficient training and experience or knowledge as to enable him to assist in securing
compliance, on the part of the employer, with the necessary safety legislation and maintenance
procedures”.
It is expected that those persons designated as Competent to have had:
Valid certificated training, where this is deemed necessary, including an element of health and
safety appreciation, relevant to the Permit to be issued.
Experience of the work to be carried out.
Knowledge of the Permit-to-Work procedures.
8.4 Monitoring the Work
As far as is reasonably practicable, the Competent Person shall be responsible for monitoring the
work at regular intervals, to ensure that the operatives are adhering to the conditions of the permit.

63. 63
8.5 Completed Work
When the work has been completed the Competent Person will inspect the site to ensure that:
 The works have ceased.
 All tools and equipment have been removed.
 The work area has been left in a satisfactory and safe condition.
When the Competent Person is satisfied that these conditions have been met the permit will be
cancelled and copies filed with the contract documents (if appropriate) and in the Permit file. These
permits should be kept for 12 months.
8.6 Out of Working Hours
Whenever possible, work that requires a Permit-to-Work should be carried out only during normal
working hours. However, there will be occasions when this is not possible and the Competent
Person must ensure that he is available to monitor contractor or staff compliance throughout the
duration of the permit irrespective of when it takes place.
Details of PPE
Method statement of work to be carried out.
Monitoring of the atmosphere.

64. 64
Chapter 9
PERMIT TO WORK 2 (ELECTRICAL SYSTEMS)
9.1 High Voltage
The Permit-to-Work system for High Voltage applies to contractors and staff who may have need
to enter any High Voltage substations. It DOES NOT allow for switching of the H.V. circuits or
for maintenance of the equipment, this can only be carried out by authorised SEEBOARD staff.
 The duration of the Permit-to-Work will be no longer than a maximum of one day. For
work that may take longer than the one day, a separate permit should be issued for each
day.
 Requirements to be met to enable access to the substation;
 The Competent Person must ensure that access to the substation will not in any way effect
the H.V. switchgear or controls.
 The Competent Person must stay at the substation if access is required for 1 hour or less.
For periods of more than 1 hour the Competent Person must be available on the premises
and be within immediate communication with those in the substation.
 Only those staff named on the Permit-to-Work will be allowed in the substation.
 The substation must not be left unlocked and unattended.
9.2 Low Voltage
Low voltage is regarded as a voltage exceeding 50v AC or 120v DC between conductors or earth,
but not exceeding1000v AC or 1500v DC between conductors or 600v AC or 900v DC between
any conductor and earth.
Requirements to be met when working on low voltage electrical installations;
 The Competent Person must ensure that before disconnection or isolation of any
distribution board or circuit that feeds a distribution board, the electrical equipment
effected has been identified and if appropriate the users notified.
 That staff and contractors are aware of the need to lock-off all isolation switches in the
OFF position.

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 The Competent Person should issue a Permit-to-Work when any of the following work is
carried out on low voltage electrical installations;
 Switching off any switch fuse, distribution board, or mains circuit board that may affect
the University’s IT systems, the safety of any person, or the electrical supply to fire alarm
systems.
 Work on remote and automatically controlled low voltage switchgear.
 The duration of the Permit-to-Work will be issued for a maximum of 5 working days and
should be location specific.

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Chapter 10
ELECTRICAL EMERGENCY RESPONSE TECHNIQUES
10.1 Electrical Rescue Techniques
 Approaching the accident.
 Never rush into an accident situation.
 Call rescue telephone lines as soon as possible.
 Get the aid of trained electrical personnel if possible.
 Approach the accident scene cautiously.
 Examining the scene:
Visually examine victims to determine if they are in contact with energized
conductors. Metal surfaces, objects near the victim or the earth itself may be energized. You may
become a victim if you touch an energized victim or conductive surface. Do not touch the victim
or conductive surfaces while they are energized. De-energize electrical circuits if at all possible.
10.2 Methods to De-energize:
 An extension or power cord probably powers portable electrical equipment.
 Unplug portable electrical equipment to remove power.
 Open a disconnecting device or circuit breaker to de-energize fixed electrical equipment.
10.3 Hazards and Solutions:
 Be alert for hazards such as stored energy, heated surfaces and fire.
 If you can’t de-energize the power source use extreme care:
 Ensure that your hands and feet are dry.
 Wear protective equipment such as low voltage gloves and overshoes if available.
 Stand on a clean dry surface.
 Use nonconductive material to remove a victim from the conductor.
10.4 High Voltage Rescue:
 Special training is required for rescues if high voltage is present.

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 Protective equipment such as high voltage gloves and overshoes must be worn.
 Special insulated tools should be used
10.5 Insulated Tools:
 Insulated tools, with high voltage ratings, are a lifesaver!
 Use devices such as hot sticks or shotgun sticks to remove a victim from energized
conductors.
 In some cases, nonconductive rope or cord may be used to remove a victim from a
conductor.
10.6 Rescuing the Victim:
 Stand on a dry rubber blanket or other insulating material if possible.
 Do not touch the victim or conductive material near the victim until the power is off.
 Once power is off, examine the victim to determine if they should be moved.
 Give “First Aid.”
10.7 First Aid:
 A victim may require Cardio-Pulmonary Resuscitation (CPR).
 If the victim is breathing and has a heartbeat, give first aid for injuries and treat for shock.
 Ensure the victim gets medical care as soon as possible.
 Provide medical personnel with information on voltage level, shock duration & entry/exit
points.
 The treating/attending physician must have detailed specific information to properly
diagnose and care for the victim. The physician must determine whether the victim should
be sent to a “Trauma or Burn
10.8 Center:
 Stay with the victim until help arrives.

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CHAPTER 11
CONCLUSION
The health and safety programs have been elaborated in order to prevent the risk of work related
incidents and to facilitate safety when working in electrical environment especially at distribution
level. Health and safety laws requires the employers to look after the health, safety and welfare of
their employees. They also must consider who could be affected with their work, their clients,
contractors and visitors to their premises. Employers also have a duty identify, assess and control
safety risks and must write down the significant findings of their risk assessment if they have five
or more employees.
Providing a safe working environment need not be a difficult or time consuming exercise,
particularly if in a low risk environment. The most important thing is to make safety part of our
business culture driven by a commitment from the top of the organization. Benefit of working
safely include fewer accident, reduce insurance premiums, a better motivated workforce and peace
of mind.
Employees who ever involve in Electrical works both at construction and operational level, they
have to know their right, safety and safety and health and what the company care and responsible
on them. All the regulations and conditions at site are important to everybody who is at the site
because they are always at risk. The company has to ensure the works under its control and carried
out in such a way to minimize the risk to health and safety for employees and any other person
who could be affected. If the aforementioned control measures are fully implemented, a safe
working environment will be guarantee.
We must always remember it is our right to live, invariably it is our right to work in a safe
environment, through cooperative efforts between employers and employees can learn to identify
and eliminate or control electrical hazards, because safety is everyone’s business.
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REFERENCES
1. Charles K. Alexander, Matthew N. O Sadiku, (2004) "Fundamentals of Electric Circuits
"2nd
Edition, McGraw, Hill publishing.
2. Institute of Safety Professionals of Nigeria (2012) "General Health Safety Environment
Training Manual" Nigeria.
3. Institute of Safety Professionals of Nigeria, (2012) "Contractor Employee Health Safety
Environment Training Manual Level 3", Nigeria.
4. Electrical Safety Foundation International (2008 ) " Electrical safety Workbook",
5. Occupation Safety & Health Council (2006) "Note on Electrical Safety ".
6. Occupational Safety and Health Administration (2006)," Fire Service Features of
Buildings and Fire Protection Systems ", United State of America.
7. Code of Practice (2012) " Managing Electrical Risks in Workplace " Australia,
8. John J. Shea, "Identifying Causes for Certain Types of Electrically Initiated Fires in
Residential Circuits" Electrical Eaton Corporation, Pittsburgh.
9. North Delhi Power Limited, (2007) "Electrical Safety Manual" (A Tata Power and Delhi
Government Joint Venture),India.
10. Workplace Safety & Environmental Protection (2012), "Electrical Safety Guide For
Non- Electrical Workers ".
11. Frederick F. Franklin, (1991) "A survey of Electrical Fire".
12. International Association of Oil and Gas Procedures(1993)"Guideline on Permit to
work "
13. Nagrath I.J, Kothari D.P,(2006)"Power System Engineering",Tata McGraw-Hill
Publishing Company Limited, India.

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