New Grumman owner was flying his plane with an instructor when the main alternator breaker popped. The instructor pushed it back in and it stayed there for about 4 minutes when it popped again with a puff of smoke. So they turned back to the airport and practiced electrical conservation.

After checking all the wiring for shorts (new plane power alternator and voltage regulator) that left the circuit breaker itself. A first for me. After replacing it with a serviceable used one, here is how the old one looked. To quote the owner, “Nothing lasts forever!”