Have You Been Exercising Your Breakers?
Properly maintained circuit breakers should operate well for many years. However, over time they collect dust and dirt which does not allow heat to dissipate. Trip coils burn out. Internal grease hardens. Oxidization and corrosion can occur, and breakers fail to perform properly.
Neglected circuit breakers can cause serious issues. The breaker may fail to open on time or not at all, resulting in an arc flash or a fire, damage to persons or equipment, or unintended outages. Nuisance tripping can also occur. Did you know circuit breakers not properly maintained can have up to a 50% failure rate over a 5-year period?
Manually exercising the breaker by turning it off and on 3-4 times helps to keep the contacts free and clean and helps ensure the internal mechanisms of the breaker are operating freely. Breakers SHOULD NOT BE exercised under load.
Generally, moulded case circuit breakers are rated for 3 faults or fewer. Breakers which have a history of trip conditions should be replaced.