I would start with checking the splices in the boxes and looking to see if they did daisy chain thru the receptacles.
While 99% of all house power electrical contractors love do daisy chain thru devices cause it cheap easy and fast, pay close attention to the neutral!! That is where the problem...
Looking for way to correct problem in exsiting switch gear that utilizes 5/16" all thread to hold C channel barrier for buss spacing, from heating... temp. showing 54.6 C on all threads, buss running at ambient room temp.
Am considering covering all tread with tublar barrier board.
Thanks...
