Strange deal on multiple receptacles in a house, over numerous circuits. Plug in a small appliance, not turned on, and then pull the cord out. It sparks on both probes of the cord just as it clears the receptacle, although it "seems" to me that it is brighter arc on the nuetral. Service grounding seems good, everything tight in panel. The one receptacle opened so far had 3 cables with all conductors in quick locks. Fixed that but it still does it??