Earth Leakage Circuit Breaker

Earth Leakage Circuit Breaker

1. Sardar Vallabhbhai Patel Institute Of Technology, Vasad Elements of Electrical Engineering Name :-Patel Milan A. Enrollment No.-150410101040 Topic:-Earth L eakage C ircuit Breaker

2. What are Circuit Breakers? A circuit breaker is an automatically operated electrical switch designed to protect an electrical circuit from damage caused by overload or short circuit. Its basic function is to detect a fault condition and current flow. Unlike a fuse, which operates once and then must be replaced, a circuit breaker can be reset (either manually or automatically) to resume normal operation .

3. ELCB-Earth leakage circuit Breaker:- An earth leakage circuit breaker ( ELCB ) is a safety device used in electrical installations with high earth impedance to prevent shock. It detects small stray voltages on the metal enclosures of electrical equipment, and interrupts the circuit if a dangerous voltage is detected. Once widely used, more recent installations instead use residual current circuit breakers which instead detect leakage current directly .

4. It is used for the protection against electrical leakage in the circuit. When somebody gets an electric shock or the residual current of the circuit exceeds the fixed value, ELCB cuts off the power within the time of 0.1s automatically protecting the personal safety and preventing the equipment from the fault. ELCB also protect the circuit against over load and short-circuit .

5. Why we Use ELCB?:- The main purpose of earth leakage protectors is to prevent injury to humans and animals due to electric shock .

6. Construction:-

7. PRINCIPLE OF OPERATION: It is a current operated device designed to operate when a leakage current exceeds a pre-determined value. It essentially consist of an operating coil & a trip mechanism which operates contacts controlling the supply to the circuit concerned. Consider a single-phase circuit. The two supply wires i .e. phase & neutral are fed through separate winding of current transformer as shown in the fig: another winding controls the tripping mechanism.

8. ADVANTAGES :- They are less sensitive to fault conditions , therefore have less nuisance strips. They can be arranged to protect against cable damage only. And not strip on faults in down line installations .

9. DISADVANTAGES :- They do not detect faults that don’t pass current through the CPC to the earth rod. They do not allow a single building system to be easily spilt into multiple sections with independent fault protection, because earthing system are usually bounded to pipe work. ELCBs introduce additional resistance & an additional point of failure into earthing systems .

10. Thank You