Faulty breaker or other cause?

[CharlieJ]

Blue Sea Systems will replace the failed breaker; no questions asked.

[Suijin]

Postscript: I was on the phone having a long conversation and picked up the old breaker and was absently playing with it in my free hand, repeatedly flipping the toggle. As I ended the call I realized the switch was staying on after all that “exercising”. Contaminated toggle that cleaned itself? Who knows. While I won’t count on it as a primary backup I’m not going to throw it out. Returning it for exchange would not be worth the trouble as they are $15 online.

[Cpt Pat]

Originally Posted by Cheechako

Faulty Marine breakers are quite common. Replace it. I had two go out within a week of each other. not overloaded, or warm etc. just kept flipping off.
Interestingly, I helped build a group of small boats for the Marine Corps. Their spec didn't allow breakers, only fuses.

Breakers get corroded. "Rust never sleeps." I will only use breakers inside the cabin, never on a weather deck.