Tripping Sub Feed

[kwired]

All these posts about nuisance tripping on mains!
Try installing a FP breaker =0 there...
30amps should be plenty!

Sorry... couldn't "resist" :slaphead:

But they don't easily fit in anything but a FPE panel.

 

[GoldDigger]

But they don't easily fit in anything but a FPE panel.

Since it is not actually going to do anything, do you have to wire it in or can you just mount the shipping box next to the existing panel?

 

[Little Bill]

Maybe I missed it, but I don't recall reading where the sub panel is a main breaker or MLO.

If it's a main breaker, which breaker is tripping, the one in the house main that is feeding the sub, or the 125A main in the sub?

 

[templdl]

The suggestion to temporarily replace the 125a breaker is strictly diagnostic. The reason for the suggestion of using something smaller is, as someone already said, it is likely to be on hand.

Who pays for this? Is this a case of replacing or exchanging parts until you get lucky?

 

[kwired]

Maybe I missed it, but I don't recall reading where the sub panel is a main breaker or MLO.

If it's a main breaker, which breaker is tripping, the one in the house main that is feeding the sub, or the 125A main in the sub?

Why does it matter? It is still carrying the feeder load - which we think is an acceptable load for 125A overcurrent device.

 

[Little Bill]

Why does it matter? It is still carrying the feeder load - which we think is an acceptable load for 125A overcurrent device.

Well for one, it would narrow down the search for the problem. Although I don't think it's in the feeder.

If you got a call saying the 125A breaker was tripping and you knew there was a house main feeder breaker and one at the sub panel, would you not ask the HO which breaker was tripping?

 

[kwired]

Well for one, it would narrow down the search for the problem. Although I don't think it's in the feeder.

If you got a call saying the 125A breaker was tripping and you knew there was a house main feeder breaker and one at the sub panel, would you not ask the HO which breaker was tripping?

Yes, but I am also assuming the OP is past that point and knows which one is tripping.

 

[Little Bill]

Yes, but I am also assuming the OP is past that point and knows which one is tripping.

He does, but we don't, and he's asking us!