Electrical Safety

Electrical Safety
Unqualified Worker

© Business & Legal Reports, Inc. 0605
Session Objectives
This training session covers electrical safety for unqualified
workers. “Unqualified” workers are those such as machine
operators, operators of powered industrial trucks, construction
workers, and others who are not qualified to perform electrical
work, but who need to know important information about the
hazards of electricity and how to prevent serious injury.
For workers who are authorized to work on or near energized
electrical equipment and wiring, additional training is required.
You will be able to:
•Understand the hazards of electricity
•Identify and avoid common electrical hazards
•Follow safe work practices around electrical equipment

How Does Electricity
Work?
How does electricity work? In order to recognize and avoid the hazards,
it’s important to understand the basics of electricity.
• Electricity is the flow of electrons, similar to the flow of water through
a pipe. All electricity follows what’s known as “Ohm’s Law”: E, or
voltage, equals I, or amperage times R, or resistance. Let’s compare
electricity to the flow of water in a pipe to explain the relationship
between voltage, amperage, and resistance.
• Voltage can be compared to pressure. The higher the voltage, the
more likely it is to cause injury, just like the difference in force
between high and low water pressure.
• Amperage can be compared to flow. Higher amperage means a
higher volume of electricity, in much the same way as a larger
diameter pipe will allow a greater flow of water than a small-diameter
pipe.
• Finally, resistance can be compared to restrictions in a water pipe.
When electricity has resistance, this generates heat, which can result
in fires or damaged equipment.

Electrical Hazards
Here are some of the more common electrical hazards that you
might encounter:
• Contact with power lines, either overhead or buried in the
ground, or contact with equipment that is touching these lines.
• Contact with electrical equipment or tools that are damaged.
• Improper wiring that can cause a short circuit.
• Overloading of circuits or wiring; or
• Unsafe work practices, such as using an aluminum ladder
near or against power lines.
Take a moment to think about some of the potential electrical
hazards you might encounter in your workplace.

Electrical Injuries
Electrical injuries can be very serious, and sometimes even fatal.
Here are some common types of electrical injuries:
• Cardiac arrest and respiratory failure resulting from electrical
shock or electrocution.
• Muscle, nerve, and tissue destruction from electrical current
passing through the body.
• Burns from arc flash and arc blast.
• Thermal burns from contact with sources of electricity; and
• Secondary injuries, such as falling from a ladder after
receiving an electrical shock.

How Electrical Shock
Occurs
In basic terms, here is how electrical shock occurs:
• Fundamentally, a shock occurs when electrical
energy contacts your body.
• A shock can occur when you contact two wires
that are at different voltages. An example would
be touching the “hot” and “neutral” wires of a
standard 120-volt system. Another example is
touching different phases in a 480-volt, three-
phase system. If there is contact with live wires
or other electrical components, this suggests that
they are not insulated or enclosed properly.
• Another way to get shocked is for you to become
a part of the path between a live wire and the
ground. Electricity always takes the path of least
resistance, and your body can become part of the
path because it is a good electrical conductor. If
you touch a live wire with your hand, electricity
can travel through your body and exit through
your foot. This kind of electrical shock is,
unfortunately, very common.

Severity of Electrical Shock
The severity of an electrical shock depends on a number of
factors:
• First, the amount of electrical current—the more current,
the more dangerous it is.
• Second, the duration, or length of time, the current
passes through the body. The longer the duration, the
more dangerous it is.
• Finally, the specific path the current takes through the
body; it is most dangerous if it travels through the heart.
Note that you cannot know the path the current might take
through your body once it enters.

Effects of Electrical
Current on the Body
CURRENT
1 SECOND
BODY’S RESPONSE
0.5 – 3 mAmp Faint, tingling sensation
3-5 mAmp Slight shock, minor muscle contraction, can control muscles
6-30 mAmp Painful shock, muscle contractions severe, cannot control muscles
5-150 mAmp
Extremely painful shock, respiratory arrest, severe muscle
contractions, death may occur
1 – 4 Amp Ventricular fibrillation, nerve damage, death is likely
10 Amp Cardiac arrest, severe burns, death is probable
15 Amp Lowest overcurrent protection of common fuse or circuit breaker

Effects of Electrical
Current on the Body
The table on the next slide shows the effects of different flows of
electrical currents on the body when the current flows for one second.
Note that the designation “mAmp” means milli-amp, or one one-
thousandth of an amp.
You’ll see that a small fraction of one amp of electricity is enough to
cause a painful shock, respiratory arrest, and even death. At more than
one amp, cardiac arrest and death is likely.
Now think about common everyday electrical equipment and appliances.
For example, a 100-watt light bulb has 833 milli-amps of electricity
flowing through it, which could be enough to kill you. A typical kitchen
toaster has more than 9 amps of current, which is certainly enough to kill
you. So remember, the electrical equipment we use every day has
enough current to cause serious injury and death if we’re not careful.

Injuries from Electrical
Shock
Electrical shock causes many kinds of serious injuries.
• “Electrocution” simply means that the shock is
powerful enough to cause death. Hand-held power
tools typically carry more than enough current to
cause electrocution.
• Injuries from electrical shock happen because
electricity follows the path of least resistance which,
in the body, means your blood. Electrical current
can damage nerves and body organs. Burns occur
because of the resistance of the body as electricity
flows through it.
• Secondary injuries occur when someone receives an
electrical shock and as a result has another type of
accident. An example would be someone on a
ladder with an electric drill, who receives a shock
and falls off the ladder. Another example would be
someone working on a machine who gets a small
shock that causes him to pull his or her hand or arm
back quickly, striking a piece of metal and causing
serious trauma to the hand or arm.

Image Credit: OSHAImage Credit: OSHA
Arc Flash and Arc Blast
“Arc flash” and “arc blast” are types of
electrical accidents that are extremely
dangerous.
• An Arc Flash occurs when electricity
travels through the air. This can
happen when electrical devices such as
circuit breakers and disconnects are
opened and closed, when energized
equipment is touched with a tool, or
when equipment fails. An Arc Flash
last only a fraction of a second, but it
can create temperatures of up to
35,000 degrees, which is enough to
vaporize metal. Needless to say, an
Arc Flash causes severe skin burns.
• An Arc Blast is a pressure wave from
an Arc Flash—it is essentially an
electrical explosion that causes severe
injuries and death, as well as major
damage to facilities and equipment.

Electrical Burns
• Electrical burns are a very common and
serious injury caused by electrical shock.
• Electricity in the body generates heat,
because the body produces resistance.
The heating of body tissues results in
electrical burns.
• Second-degree and third-degree burns
can appear on the skin, or they may
be internal, so that the person may not
look to be seriously injured.
• While electrical burns may look minor
from the outside they might be severe
on the inside, due to the damage they
have caused to internal organs and
tissues.
• Thermal burns also can occur from
contacting surfaces that are extremely hot
due to electricity, or when clothing or
equipment catches fire.

Electrical Hazards—
Any Questions?
Do you understand the hazards of electricity and the injuries it can cause in the
workplace? Now it’s time to ask yourself if you understand the information presented
so far.
• It is important for your safety that you understand the hazards of electricity and the
injuries it can cause.

Emergency Response
and First Aid for Shock
Now we’ll discuss what to do in the event of an
electrical shock, and review the safe practices and
procedures that will help make sure an electrical shock
doesn’t happen in the first place.
Proper emergency response and first aid can be a
lifesaver in the event of an electrical shock. If a person
is shocked:
• Do not touch the person if he or she is still being
shocked. The electrical charge could pass through
to you.
• Shut off the electrical equipment that is causing the
shock, if the shock is continuing.
• Call for trained first aid personnel immediately; or
• If you are appropriately trained, administer first aid
and cardiopulmonary resuscitation (CPR) as
necessary. Since shock often causes ventricular
fibrillation, you may need to use an automated
external defibrillator, or AED, to monitor the
situation and help start the heart beating properly
again.

Stay Away from Power
Lines
Now let’s go on to discuss ways to avoid electrical shock in the first place.
One very good rule is to stay away from power lines.
• For overhead power lines:
• Stay at least 10 feet away.
• Keep equipment at least 10 feet away; and
• Add four inches to the 10-foot distance for every 10 kilovolts over 50 kilovolts. That
means that if the voltage of the power line is 138 kilovolts, the minimum safe distance is
13 feet instead of 10 feet.
• For buried power lines, don’t dig any significant holes or trenches in the ground until you have
confirmed that there are no buried power lines or other utilities in the area. This is often
known as “Call before you dig.”

Report and Don’t Use
Damaged Equipment
Damaged equipment can result in
serious electrical hazards. Stop using,
and report to your supervisor:
• Any damaged electrical covers on
electrical panels, junction boxes,
and other equipment where live
electrical parts and wiring may be
exposed.
• Damaged tools that may expose
live electrical parts and wiring to a
person. Report the damage to your
supervisor.
• Electrical cords, which are easily
damaged, exposing live wires.
• Damaged equipment.

Ensure Electrical
Equipment Is Grounded
Ensuring that all electric-powered equipment is properly grounded is another
good way to prevent an electrical shock.
• If there is no safe path to the ground, exposed parts can become energized.
The purpose of grounding is to provide a safe path for electricity to travel to
the ground. If the grounding path is broken—for instance, by not having a
ground prong on a plug—electricity will take the path of least resistance,
which may be through your body.
• Electric power tools and equipment must be grounded or double insulated.
Double-insulated tools do not have to be grounded, because they are
designed not to have electrical hazards as long as their insulation has not
been damaged. This kind of equipment will show a “D” in a box, or will bear
the words “Double Insulated.” If these designations aren’t there, then the
equipment should be grounded.
• Remember that the path to ground must be continuous. If there is a break in
the path, then the current may flow to you rather than to ground.

Ground Fault Circuit
Interrupter (GFCI)
A Ground Fault Circuit Interrupter, or GFCI,
provides excellent protection against
electrical shock.
• A GFCI can detect if there is a current
flowing between two circuit wires, and
will trip, or shut off the current, before a
serious shock can occur.
• GFCIs trip at about 5 milli-amps in a
fraction of a second.
• It is still possible to receive a brief
shock before the GFCI trips.
• If a GFCI keeps tripping, then a serious
problem may exist. Don’t assume that
the GFCI is defective and substitute a
non-GFCI outlet. Instead, have a
qualified person check for the cause of
the tripping.
• Finally, GFCIs need to be periodically
tested. The test button should be
pushed according to the manufacturer’s
instructions

Follow Lockout/Tagout
Procedures
Following lockout/tagout procedures is an
essential way to prevent serious electrical
shock. These procedures lock, block
access to, or warn people away from
sources of electricity and other hazardous
energy used by machines and equipment
while they are being repaired or serviced.
• Devices that prevent access to
hazardous energy, or that clearly warn
people to stay away from hazardous
energy, are known as lockout/tagout.
• Lockout ensures that equipment is not
accidentally restarted, by making sure
that it is shut down, de-energized, and
locked.
• Tagout is used where lockout is not
feasible. It involves placing warning
tags on the equipment.
• Always follow the requirements of the
lockout/tagout program and procedures
in your workplace.

Follow Safe Work Practices
Follow safe work practices for working around electricity. Most such practices are
simply common sense rules to keep you from being shocked.
• Only qualified persons—generally, trained electricians wearing the right
protective equipment—are allowed to work on or near exposed electrical
equipment or wiring.
• Don’t wear clothing that can conduct electricity when working with electric-
powered equipment. This includes anything with metal, such as metal-
rimmed glasses or wire-mesh gloves.
• The work area should be well-illuminated so that you can see if there are any
electrical hazards present.
• Don’t use conductive liquids such as water—or for that matter, any conductive
items—anywhere near exposed electrical equipment.
• Do not defeat or try to circumvent electrical interlock devices.
• Finally, use nonconductive ladders for working anywhere near electrical
equipment. Generally, this means wooden ladders only.

Use Portable Electrical
Equipment Safely
Make sure you know how to use portable
electrical equipment, such as power tools,
safely. Before you use such equipment:
• Inspect it for damage. Never use it if it
smokes or sparks.
• In particular, make sure the cord is not
damaged and that the ground prong is
present, unless it is a double-insulated tool.
• Use the equipment safely:
• Don’t lift portable electrical equipment
by the cord, or pull the plug by tugging
on the cord. This could damage the
connection from the cord to the
equipment.
• Make sure your hands are dry before
plugging or unplugging electrical
equipment; and
• Always plug the equipment into a GFCI
outlet if the work area is wet or has
moisture present.

Circuit Protective Devices
Circuit protective devices are designed to protect you against possible
electrical shock, so understand their purpose and what to do if they trip.
• Devices such as circuit breakers and fuses are intend to allow a
certain amount of amperage into the circuit before tripping, blowing,
or otherwise breaking the circuit. They are designed to protect wiring
and equipment in the system from being damaged by too much
current.
• Don’t reset a circuit breaker or fuse unless you are authorized to do
so. If something trips or blows, that may be a sign of a problem, such
as a short or some other hazard. An authorized employee should
inspect the system before it is re-set.
• Finally, for any problem involving a circuit protective device, call a
qualified person to investigate rather than taking chances with a
potential electrical hazard.

Stay Away from Electrical
Work Areas
It’s extremely important to stay
away from electrical work areas –
that is, areas where qualified
personnel are working on
energized electrical equipment.
• These areas need to be
isolated so that unqualified
personnel are not exposed to
electrical hazards.
• Alerting techniques used to
keep these areas isolated
include safety signs and tags,
barricades, and attendants
guarding the area. Never try to
go around or ignore these
warning methods.

Follow the Electrical
Safety Program
Always follow the rules and guidelines in our electrical
safety program.
• This written program includes responsibilities,
procedures, safe work practices, and personal
protective equipment for work that may involve
electrical hazards.
• And remember that only qualified personnel, such
as licensed electricians, may work on or near
exposed, energized electrical equipment.

Safety Practices—
Any Questions?
Now it’s time to ask yourself if you understand the
information presented so far on electrical safety
practices. In the previous slides, we’ve covered:
• First aid
• Electrical equipment
• Electrical circuits
• Lockout/tagout
• Safe work practices
• Our electrical safety program
It is important for your safety that you understand
these topics.

Key Things to Remember
The key things to remember about electrical safety include the following:
• Exposure to electricity is dangerous—it can cause electrocution,
shock, electric and thermal burns, arc flash and arc blast burns, and
secondary injuries such as falls.
• Watch carefully for possible electrical hazards—for instance, never
use damaged tools, cords, or electrical equipment.
• Always follow safe work practices, including proper emergency
response procedures.
• Always follow our electrical safety program, which is designed to
protect you and other workers from electrical hazards.
• And finally, seek assistance from a qualified person whenever you
have any doubt about electrical safety or think there might be an
electrical hazard. Too many things can go wrong with electricity for
you to take risks.
This concludes the training session on Electrical Safety.

Electrical Safety

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