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Is it possible for an auto-resetting circuit breaker to go bad, or 'go weak'? In other words, assuming all circuit integrity is in good shape and the motor (window, power seats, etc) is not overloading the circuit, can a breaker start tripping intermittently at lower amperage than it was originally rated for when new? If so, is there a way to bench test the breaker? Thanks all.
A few more questions (and please forgive the vast breadth and depth of my ignorance):
1. Unfortunately the circuit breaker I want to measure the tripping point on is 30A. My regulated DC power supply rated output is only 0-30V/0-10A. If I were to buy another unit capable of rated output 0-30A, would I be connecting the circuit breaker ALONE to the leads (setting CV at 12V and slowly bringing up current)? Or would I need to add a load, such as a minimum 360 watt load (P=V×I)? This is probably only the third time I've used the power supply so knowledge is limited.
2. Same questions if I were to use rheostat on a spare battery?
3. If I were to use battery/rheostat method, I don't have a rheostat on hand, but searching internet seems only ones I can find rated up to the power I need to test circuit breakers are PWM rheostats, (which I thought would be good for future testing of motors, etc also). I assume these would work if I am connecting leads to circuit breaker ALONE (of course realizing rheostat would be in series), but would these work if I needed to add a load and wanted to use lamps as load? Or in the case of lamps must I only use wire-wound rheostat?
Automotive self resetting CBs are not very accurate, and they are meant as last resort to interrupting a circuit and then retrying after a reset period due to a critical function need after the fault is cleared. If they are forced to cycle due to a faulty load or shorted wire then the contacts can pit and wear out. But, this is not the fault of the CB it is a fault of the circuit it is protecting. You must first clear the fault and then replace the CB.
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