3. An Important Quote…
Concern for Man Himself and
for His Safety must always from
the chief interest of all technical
endeavor.
SN 3
4. Introduction
Electricity is the set of physical
phenomena associated with the
presence and motion of matter
that has a property of electric
charge.
SN 4
5. Basic Principles
Electric current always flows throug
a conductor.
Always passes through a
conductor.
Ultimately reaches into the earth
surface.
SN 5
6. Definitions
Current
Charge flowing through a conductor
in unit time. Unit of measurement is
Amp.
Voltage
It is a pressure from which the charge
flowing through a conductor in unit
time. Unit of measurement is Volt
Resistance
Resistance is any conditionwhich
retards current flow. Unit is Ohms.
SN 6
7. Hazards of Electricity
• Electrical shock
• Electrical fire
• Flash over
• Radiation
• Explosion
• Indirect effects
SN 7
8. Hazards of Electricity
• Electrical Shock Shock occurs when the body becomes part of the electric
circuit.
- Contact with Both Wired of the Electric Circuit
- With one wire of an energized circuit and the ground
- Touching Energized Metallic Part and standing on
Ground
SN 8
9. Hazards of Electricity
• Electrical Fire Fire in an Electric Circuit happens because of the
following reasons.
- Over Loading.
- Incorrect Fuses/Protective Devices.
- Poor Maintenance
SN 9
10. Hazards of Electricity
• Explosion Electricity does not explode in itself but aids in causing
explosion if;
- Presence of explosive fumes/vapours.
- Presence of flammable gas cylinders in the vicinity of
the flames/arcs
SN 10
11. Hazards of Electricity
• Flash over
An electric arc (sometimes referred to as “electrical
flashover”) is a continuous electric discharge of high
current which flows through an air gap between
conductors.
This generates
- a very bright ultra-violet light
- intensive heat.
SN 11
12. Hazards of Electricity
• Indirect effects
Some of the indirect effect of electricity, when a person
received electrical shock is;
- Fall
- Drowning
- Cut & Abrasion
SN 12
16. Severity of Electrical Shock
The severity of electrical shock depends on :
1. the path the current travels
2. the amount of voltage, and
3. the type of current (AC or DC)..
SN 16
17. Alternate Current (AC) vs Direct Current (DC)
(1) Current of 60 mA of AC can
cause fibrillation
(2) AC is more dangerous to our
Heart
(3) Four times severe than AC
current
(1) Current of 300–500 mA
of DC can cause fibrillation
(2) DC is more dangerous to our
body. More likely to freeze the
victim
(3) Relatively Safer than AC current
AC DC
SN 17
20. Legal and Other Requirements
Indian Electricity Act, 2003 Indian Electricity Rules, 2005 National Electricity Code
SN 20
21. Legal and Other Requirements, IE Rules, 2005
Rule-3: Authorisation
Provides provisionfor authorizationby a supplier or a consumer
Rule 29: Construction, Installation, Protection……
Ensure safety of human beings, animalsand property”
The consumer shall also ensure that the installationunder his control is maintainedin a safe condition.
Rule 30: Service Lines and Apparatuson ConsumerPremises……
Rule 31: Cut out at Consumer Premises……
Provide a suitable cut-out in each conductorof every service-line other than an earthed...
Rule 35: Danger Notice……
Affix permanentlyin a prominentposition a danger notice in Hindi English or local language...
SN 21
22. Legal and Other Requirements, IE Rules, 2005
Rule-36: Handling of Electrical Supply Lines
Stipulatesto ensure adequatesafety precautions before handlingof electric supply lines and apparatus
Rule 41: Distinction of DifferentCircuits……
Meansof indication of permanent nature.
Requirementof affixinginstructions for restorationof persons suffering from electric shock
Rule 44: Instruction on Restorationof Personsreceiving electrical shocks……
Rule 44A: Notification of Accidents
Information shall send to the Inspector a telegraphic report within 24 hours
Rule 45: Precautions to be adopted by Consumer
Measures to be adoptedby consumers, Owners, occupiers, electrical contractors, electrical workmen and suppliers…
SN 22
