Molded case circuit breaker maintenance

The circuit breaker maintenance is very important and it must added in  periodical maintenance schedule.Why it so important?It is because of their importance for routine switching and for equipment protection and person.

Production will stop if circuit breaker fails to operate because of a lack of preventive maintenance.The cost will rise for repairing jobs and it not good for business.We must avoid from this unwanted situation because of not done the circuit breaker maintenance.

The need for maintenance of circuit breakers is often not obvious as circuit breakers may remain idle for long periods of time. Breakers that remain idle for 6 months or more should be made to services to ensure it in proper condition and remove any dust or foreign material on mechanism and contacts.

Maintenance of Molded case circuit breaker

Normally Molded case circuit breakers are designed for no routine maintenance.For long life span,reduce breakdown and safety issued,we must perform for preventive maintenance depending on working condition.

The common problem effected for circuit breaker operation and capability is a dust.Normally dust on the latch surfaces may affect the mechanism and life span for circuit breaker.

1) Cleaning a dust

The major factor for malfunction of molded case circuit breaker is a dust.When it too many stick at terminal connection and mechanism,it will cause a high resistance and tripping device not function properly.

It a serious error and it must not happened because it can cause a damage for equipment and for more danger if involve with human life.

Normally every 6 months we must perform dust cleaning for MCCB using vacuum cleaner,dry compress air or smooth brush.Please make precaution about safety issue and isolated the power supply before perform the cleaning jobs.

2) Tightening the terminal screw

To ensure the molded case circuit breaker have a more life span and avoid to serious damage,every 6 months we must tightening the terminal screw for connection to avoid electric sparking when it loose connection.

Cable will damage and burn if termination for screw is loose.The electric sparking can cause the fire and will effected to molded case circuit breaker reliability and functioning.Use a suitable hand tools and follow manufacture standard torque limit for tightening the screw.

3) Test tripping device

This matter is very important to make sure the tripping mechanism in good condition and functioning because it is a main duty for circuit breaker.Test trip can be done every 3 years.If you not sure how to perform the test,please refer to electrical engineer or electrical contractor.


  1. haitham hashim says

    Important and valuable information Thank you for your efforts

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