bad breaker and repair fault

bad breaker and repair fault

bad breaker

We are using several breakers in the industry and house for the protection of devices. if a bad breaker then there is a risk to the device, for the increasing life of devices breakers plays an important role. if bad breakers in our industry we have to check them and replace them.

MCB Bad  (Miniature circuit breaker bad) :-

Fault finding:- if breaker trip continuously.

Causes & Solution :-

1) Check incoming and outgoing supply in the breakers terminal if secondary or output supply fluctuation or supply not coming then it’s an mcb issue, the solution is to replace it with a new one.

2) if the breaker is good but it’s tripping then need to check the motor side or load side devices. The solution is to check motor winding and cable continuity.

3) Breaker trip as start then check output load and breaker size for example if the motor taking 14 ampere current and we are using 10-ampere current then its needs to be a proper rating breaker.



a) breaker off but not closing.

b) breaker not tripping automatically by a short circuit.

c) breaker not tripping by manual trip button.

d) Main Contacts not closing.



a) Breaker not closing:-

Causes: for the air circuit breaker under voltage not activated, the solution is to provide or connect the proper supply to the under voltage release coil.

Trip actuating also for the same cause. another reason is the latch of the spring is not in the proper position and it’s not operating well. the solution is to fix the proper spring.


b) breaker not tripping automatically by short circuit:-

Causes:- shunt release not getting proper supply. the solution is to make proper wiring of shunt release and provide proper supply.

it is not tripping due to dust and improper friction solution is to clean the dust and use CRC for cleaning.


c) Breaker is not tripping by trip manual push-button:-

causes:- trip push button not in the proper position or its short. the solution is to fix it properly or if short change with a new one.


d) Main Contacts not closing:-

another cause is mechanism jam due to that it’s stuck. the solution is to mechanism check and clean with lubricants.


In acb it’s important to reset after fixing the above issue.




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