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How often should I exercise the circuit breakers in my electrical panel?
Wednesday, September 7, 2022
“Exercising” circuit breakers in a residential panel means manually switching them off and then back on, one at a time. Circuit breaker manufacturers and the NFPA recommend exercising circuit breakers once a year. It helps keep the contacts clean and also spreads the internal lubrication around, to ensure that the mechnism will move freely to shut off the circuit when an electrical fault occurs. Exercising does not shorten the lifespan of the breaker.
But we recommend that you briefly shut down as many appliances as possible, especially major ones like a clothes dryers or air conditioners, before starting the process. This limits the internal flash at the contact points of the main breaker and dedicated appliance breakers.
Corrosion and internal dust build-up over time can slow down or lock-up a circuit breaker that isn’t exercised once in a while. Corrosion problems will occur sooner at breakers in an exterior panel with weather exposure. An extreme example of dust contamination is shown below at an older panel (with the dead front removed). The panel was in a wall shared with an air handler closet on the other side, and air had been sucked around the breakers and through the panel into the adjacent return air plenum for years—with a thick line of dust build-up showing at the tiny gaps between breakers.
Manufacturers and UL also recommend tripping AFCI and GFCI breakers monthly using the small test button on each breaker to verify that they are still functional. We have never met a homeowner that actually does this, but sure there are a few of them are out there somewhere. If you haven’t tested them all year, then your annual exercising of all the breakers in the panel would be a good time to also check the AFCI and GFCI devices.
When you have not exercised your breakers at all for several years, you may find that some of the older AFCI breakers make a buzzing sound but are stuck and do not trip at first try with the test button. Exercising the breaker with the on/off switch, and then trying the test button again, will often return it to working order.
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