The circuit breaker on the rear of my APC Back-UPS BX750MI-FR appears damaged. The button is recessed or misaligned and does not seem to operate normally. Is it unsafe to continue using the UPS because of a possible fire, short-circuit, or overload risk? Will it still provide backup power and surge protection in this condition, and can the breaker be replaced separately, or is replacing the entire UPS the safer option?
1 Answer
I would stop using the UPS until the breaker has been inspected or the unit is replaced. A breaker that is physically damaged may not trip reliably during an overload, so you cannot assume the protection circuitry is working correctly. Disconnect all equipment and unplug the UPS before examining it. Do not bypass, glue, or force the button, and avoid opening the case because the batteries and internal components can remain hazardous even when unplugged. If the breaker does not reset firmly or looks cracked or displaced, replacement of the UPS is usually safer and more practical than attempting a repair.
If the breaker is merely tripped, remove the connected loads and press it once to reset it. If it immediately trips again, or will not stay engaged, there may be an overload or an internal fault. Reconnect devices one at a time only if the breaker and housing look undamaged.