Ok, I admit I was making guesses based on the OP's description.
In post #21 they are asked if they measured the voltage at the end of the extension cord, and they answered 124V.
In post #22 and #23 when they described the breaker and the spider box, I _assumed_ that they meant the (very common but not universal) individual breaker for the receptacle yoke in the spider box. I also assumed that if the breaker fed more than one receptacle it would be obvious that there were other loads connected.
-Jonathan