Home Improvement → Re: Advice on powering central AC

The SO cord is more than fine, as it is in conduit. However, it must be large enough to support the 125A breaker upstream. The 100A breaker is not a problem either, although that means the continuous capacity in the trailer is 80A. Note there are separate ground & neutral blocks as required.

On the other hand, it has all the appearance of a handy-man special. Or perhaps, the SO cord was used temporarily, and then rather then spending money on new wire, it was simply run through the conduit and used. Hopefully, proper conduit fill calculations were done. (You won't find this in the tables in the back of the NEC.)

That's assuming the conduit goes all the way back to the main panel and doesn't end underneath. I would not assume anything about that job, esp. with that other cable also going into the conduit...

Rereading the OP, this subpanel is fed from a 70A breaker, so there's only 56A continuous available. I'm still not sure if the SO is big enough, but I can't really tell what size it is.

/mackey

That's right - just noticed that. Feed a 100A breaker from a 70A breaker? That doesn't make much sense.

the 100A in the interior box looks to have been a 'mains' breaker for direct from the meter feeds; it's bolted in, the busbars seem to be shaped different under i; and there is no where else that i noticed to screw the incoming lines too....

the 70A was placed in the new box outside when the pole box was replaced/expanded ( too small, damaged, water leaking in).
I'd originally thought it was simply because that's what he had with him - Family friend that has since become unavailable - but from the reaction to the feeder lines above, perhaps that's all he felt safe putting in the outside box.