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