Earth leakage circuit breaker (ELCB)

Earth leakage circuit breaker [ELCB] is a safety device used in the electrical installation with high earth impedance to prevent shock. It defects small stray voltage on metal enclosures of electrical equipment and interrupts the circuits if a dangerous voltage defects.



The main purpose of the earth leakage circuit breaker is to prevent injury to humans and animals due to electrical shock.


  • An ELCB is a specialized type of latching a relay that has buildings incoming mains power connected through its switching contacts so that the ELCB disconnects take power in an earth leakage [unsafe] condition.

  • The ELCB detects fault current from life to the earth [ground ] wire within. the installation it protects. It sufficient voltage appears across the ELCB sense coil. It will switch off power and remain off until manually reset. A voltage – sensing ELCB does not sense fault current from living to any other earthed body.

Advantages  of ELCB

  • ELCB have one advantage that they are less sensitive to the condition and therefore have fewer nuisance trips.
  • It protects the animals and human from the electrical shock.

Disadvantages of ELCB

  • They do not detect a fault that don’ts pass current through CPC to the earth rod.
  • They do not allow a single building system to easily split into multiple sections with independent fault protection because the earthing system is bonded to pipework.
  • They may be tripped by the external voltage from something connected to the earthing system such as metal pipe.
  • Electrically leaky appliances water heater, washing, machine, and coolers may cause CKL to trip.

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