Sunday, 21 December 2014

KEEP YOURSELF SAFE FROM THE HAZARDS OF ELECTRICITY

Introduction
As we are electrical engineering student, so often we have to deal with high voltage electrical instrument. Here safety is a very important issue.


So, here in this presentation I shall try to give you some ideas on electrical hazards and safety.
FUNDAMENTAL OF ELECTRICITY
FElectrical current is the flow of electrons through a conductor.
A conductor is a material that allows electrons to flow through it.
An insulator resists the flow of electrons.
Resistance opposes electron flow.
HAZARDS
Shock – Most common and can cause electrocution or muscle contraction leading to secondary injury which includes falls

Fires – Enough heat or sparks can ignite combustible materials
Explosions – Electrical spark can ignite vapours in the air
Arc Flash - can cause burns ranging from 14,000 degrees f. to 35,000 degrees f
Arc Blast – In a short circuit event copper can expand 67,000 times. The expansion causes a pressure wave. Air also expands adding to the pressure wave.
Effects on human body
More than 3 milliamps (ma): painful shock

More than 10 ma: muscle contraction
More than 20 ma: considered severe shock
More than 30 ma: lung paralysis - usually temporary
More than 50 ma: possible ventricular fibrillation (usually fatal)
100 ma to 4 amps: certain ventricular fibrillation (fatal)

Over 4 amps: heart paralysis; severe burns
How shock occurs
Current travels in closed circuits through conductors (water, metal, the human body).
Shock occurs when the body becomes a part of the circuit.
Current enters at one point & leaves at another.
Main causes of accident-
Drilling and cutting through cables
Using defective tools, cables and equipment
Failure to maintain clearance distance of 10 feet
Failure to guard live parts from accidental worker contact
Unqualified employees working with electricity
Improper installation/use of temporary electrical systems and equipment
By-passing electrical protective devices
Not using GFCI (ground fault circuit interrupters) devices
Missing ground prongs on extension cords

Some safety tips-
Make them grounded
All current carrying metal parts.
All circuits and extension cords.
Portable & semi-portable tools and equipment unless double insulated make them grounded
Use automatic shutting off technology
We can be safer by automatically shutting off the flow of electricity in the event of leakage, overload, or short circuit.  
Ground Fault Circuit Interrupters (GFCI) are circuit protection (or “over current”) devices that protect you, the worker.
Circuit breakers & fuses protect equipment, not you, because they take too much current & too much t.ime to trip
DO not reverse polarity
Make the un-covered wire elevated minimum 10 feet from your head.
Always use insulated wire
Rubber and plastic is put on wires to prevent shock, fires, short circuits and for strain relief.
It is always necessary to check the insulation on equipment and cords before plugging them in.
The first way to safeguard workers from electrically energized wires is through insulation.
Remember, even the smallest defect will allow leakage!
Don’t touch the electrical equipment with wet hand
Keep electric equipment away from children.

Conclusion-
Electricity is a bless to modern world, we can not imagine  a day without it , but sometimes it becomes curse to man,  so we have to deal with it vary care fully to keep us safe from electrical hazards, Always follow the safety tips.
Safety first
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