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Elements of Electrical Engineering presentation
Topic: - Earthing & Electrical safety
By Nikhil Pandit
CE A
A1
Enrollment no.:-130120107057
Earthing AND ELECTRICAL SAFETY
Concept of Earthing Systems
All the people living or working in residential, commercial and industrial places, particularly the person who are close with electrical systems and machineries, should essentially be protected against possible electrification.
What Is Earthing? The process of connecting metallic bodies of all the electrical apparatus and equipment to huge mass of earth by a wire having negligible resistance is called Earthing.
Grounding
There are two kinds of grounding:
• 1. Electrical circuit or system grounding
• 2. Electrical equipment grounding
Electrical System Grounding • One conductor of the
circuit is intentionally grounded to earth
• Protects circuit from lightning, or other high voltage contact
Equipment Grounding
• All metal frames & enclosures of equipment are
grounded by a permanent connection or bond
Qualities Of Good Earthing
• Must be of low electrical resistance
• Must be of good corrosion resistance
• Must be able to dissipate high fault current repeatedly
Effects of Amount of AC Current3 ma- painful shock which
cause indirect accidents
10ma- muscle contraction...”no let go” danger
30ma- lung paralysis- usually temporary
50ma- possible ventricular fibrillation (heart dysfunction, usually fatal)
100 ma-4amps- certain ventricular fibrillation(heart fail), fatal
4 amps- heart paralysis, severe burns
A FACT OF ELECTRICAL HAZARDS
Thank you