Electrical – Three hot wires,1 neutral on a switch

electricalwiring

I am trying to replace an outlet, but am having trouble figuring out how to wire it properly. The top receptacle on the outlet is supposed to be connected to a switch. When the switch is turned on the 2 blacks test hot, as well as one of the neutrals. When the switch is off, the neutral and 1 black test hot. How do I wire this properly?

Where I am at:
I broke the tab between the poles on hot side of the outlet, just like the old outlet. I also see that the pigtailed black line goes to the lower receptacle, which is always on. I think the black line that is controlled by the switch goes on the upper hot side of the line. But is it okay to have the hot neutral on the other poles?

wiring diagram

  • 3W->4W 120V
  • 1B->4W 120V
  • 2B->4W 30V when the switch is in the off position, 120V when it's in the on position
  • 3W->2B 60V

My multimeter may not be that good. It's new, but the voltages jump and I often feel like I am getting different readings.

1B & 3W are always carrying power, 4W is neutral, 2B is responsive to the switch.
There are 3 sets of wires entering the box.

Updated picture

enter image description here

1 is carrying power, 3 goes on to the remaining outlets, and 2 runs to the switch.

Best Answer

Based on your readings, the 1 side black, 2 side white(! retag this wire with black electrical tape!) and 3 side black should be nutted together and pigtailed, and the 1 side white should be pigtailed to the 3 side white apparently -- there looks to be some sort of load plugged into the outlets connected to the 3 wires, which'd explain why the 3 side white reads 120VAC with regard to the 1 side white. From there, you can then connect the white pigtail to the silver screw, the black pigtail to the lower brass screw, the 2 side black to the upper brass screw, and the bare pigtail to the ground screw.

The funny voltage readings on 2B with the switch off are due to the high impedance of your meter seeing capacitive coupling of a small amount of energy into the switched-off wiring.