Main circuit breaker

[rhb50]

I have a 2015 Itasca 27N LX (same as Vista 27N LX). Arrived at a campground, set up and 15 minutes later the main breaker shuts. I checked the outside connection and it was ok. Reset the breaker and it went off again in 10-15 minutes. This time I felt the breaker and it was hot. Turned off the AC and reset it and we had no further problem with everything on as before except the AC. Luckily we were headed home the next day after 6 weeks on the road. Two days later I went and started the generator and ran the AC for 35 minutes without any problem. I felt the main breaker and it was not hot. It felt like all the other breakers. Any ideas on what might have happened?

[BobC]

What do you mean by the outside connection was OK? Exactly how did you check it? There are numerous things that could have been wrong that a cursory check wouldn't find.

[DavidM]

The breaker contacts might have had a bit of corrosion or prior arcing that was causing a voltage drop and therefore it got hot. After a few trips it cleaned itself up.

The tripping might be due to the A/C pulling more current than normal due to the low voltage. Motors suck more current to compensate for low voltage.

I realize that both of these are a bit of a stretch, but are the only thing I can think of that explains all of the data.

You might want to replace that breaker just to be safe.

David

[BobC]

Originally Posted by DavidM

The breaker contacts might have had a bit of corrosion or prior arcing that was causing a voltage drop and therefore it got hot. After a few trips it cleaned itself up.

The tripping might be due to the A/C pulling more current than normal due to the low voltage. Motors suck more current to compensate for low voltage.

I realize that both of these are a bit of a stretch, but are the only thing I can think of that explains all of the data.

You might want to replace that breaker just to be safe.

David

I suppose it's possible this was due to a bad breaker, I suspect there was low voltage at the shore power connection (we still don't know what the OP means by it was OK). The only sure way to test this is to hook up to a good shore power connection that's putting out the correct voltage.

It's also possible that there's a resistance issue with the shore power cord (unlikely) or the shore power circuit in the transfer switch (more likely) that's causing low voltage. I'd tighten all connections in the transfer switch. It's a good idea to do this annually.

In any case, breaker replacement is inexpensive but, afterward, it still needs to be tested with a good shore power connection.