Hot backfeed breaker

[JoeNorm]

Solar backfeed breakers are interesting because they are commonly operating at their max ratings for long periods of time.

Today I had a situation where I was feeding two panels side by side with the same sized array. I measured amp output of each array to be within one amp.

One of the breakers was hot to the touch, too hot to hold a finger on for more than a few seconds. The other was just warm. I found this interesting as both breakers and panels are brand new.

How hot is too hot for a breaker to be? At what point is a hot breaker a concern?

thanks

 

[LarryFine]

That's too hot. You should check the condition of the stabs and the wire terminals. You might need a new breaker in a different pair of spaces.

 

[GoldDigger]

If it is too hot for a sustained touch, you can be pretty sure that the thermal trip curve has also been shifted to a more sensitive position, which may also lead to nuisance trips.