quote:

Originally posted by Rightwire:

quote:

Originally posted by arcwelder:
Slab on grade?

Is the attic unused space? Such that it has blown in or other insulation on the ceiling?

There could be a buried box in the attic that went bad, but didn't fail in a way that shorted.

Full basement, semi finished. Breaker box and all wiring is from the basement up into the rest of the house.

Have you actually checked the attic carefully? Previous Owners can get into all sorts of mischief and with a build in 1957 you are right smack into the DIY craze of the 60's where there were a lot of homeowners who thought they knew what they were doing but didn't. I suspect that what you may find is a junction box hidden somewhere in the basement ceiling that was added for a fridge, freezer, or lighting and tapped into your effected circuit.