I pulled an outlet out of the box to determine how far upstream it was on the circuit in preparation for installing a GFCI. Three hots and three neutrals connected to the outlet.
I disconnected all hot wires and used a non-contact detector to determine which is the line from the circuit breaker. I verified the other two were hot loads going elsewhere (i.e., not energized when I turned on the breaker -- and everything else on the circuit was off, so I got the outlet furthest upstream). I figured, OK, they're splitting the circuit left and right around the room to reach the other outlets, etc.
However, when I connect just one of the load hots, everything downstream gets power, and the other load hot that's not yet connected also has power. Ergo, the separate hot load wires connect with each other somewhere I can't see, but I have no idea why or where, since hooking up just one got power to everything.
I've never seen this before. Can anyone tell me what's going on?