Our 1950s era house has a 2-prong switched outlet by the front door. Both plugs are turned on/off by the switch next to the front door, so it's not one of those split kind where one plug is always hot and the other is switched. The outlet has 3 wires like this:
The metal between wires 2 and 3 on the left is connected, so it's not like the modern outlets where you can break the tab to stop the continuity between these 2 screw terminals.
I did an experiment where I disconnected each wire one at a time and found these results:
- Disconnected 1: Both plugs on this outlet stop working.
- Disconnected 2: Both plugs on this outlet stop working.
- Disconnected 3: Both plugs on this outlet work, but another outlet on a different wall stops working.
I held a non-contact voltage detector by each wire and it shows 1 and 3 with voltage. The really baffling part is that the voltage tester still shows voltage on 1 and 3 when the switch is turned off, but I've read that you can have "phantom voltage" so maybe it's showing that. The switch doesn't turn off the other outlet, just this one.
Does the following sound like a correct assessment?
- Wire 1 is the incoming hot for this outlet.
- Wire 2 is the neutral.
- Wire 3 is the neutral leg coming from the outlet on the other wall.
I'm also curious how the switch is involved here to turn off the outlet. Maybe Wire 1 is being turned off despite the tester showing voltage there. I also thought perhaps the switch is interruping the neutral wire 2, but if that's the case then the other outlet would be shut off too.