My client has a weird electrical setup that some shmoe installed. It seems as though I’ve spent my entire life fixing some other guy’s mistakes. Power was going out in a bathroom unexpectedly (never mind that the owner and tenant share this circuit) I finally found an old three way in the back of a closet that somehow controls the circuit and has accidentally flipped by the owner, Problem is, there seems to be no accompanying three way anywhere else. More oddly, the switch and all three wires are not energized when it is on and providing power, but shows current when it is off. Huh?
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How old is this structure? Any old knob-and-tube wiring?
I'd say it was built in the 40's, maybe later. No evidence of K&T. Neutral reversed? Hmm. How could I diagnose that? Where is the other switch? Isn't that required to make it work a all? I'm thinking that this clown must've buried it somewhere...
There was a style of wiring a 3-way, now illegal but popular with K&T, where the two switches are set on opposite sides of the fixture, with each switch choosing between hot and neutral, the commons feeding the fixture.
It is an ironic habit of human beings to run faster when we have lost our way. --Rollo May
Oh yeah! That was called the Carter system I think. The polarity may be reversed. So the neutral is carrying the load? That's why I detect no current at the switch when it's on? Jeez! Sounds like I may be opening walls to fix this. It'll be really hard to explain this situation to my client when for all intensive purposes, it appears to be working. Do you think I should just leave it be?
I'd recommend removing the switch, wire-nutting together the two wires that need to be connected, and installing a blank cover. Or just tape over the switch with several pieces of duct tape.
It is an ironic habit of human beings to run faster when we have lost our way. --Rollo May
That sounds like the plan to me. I'll just make sure that the fixtures and receptacles all have correct polarity, Thanks!
Sounds like the neutral is getting switched.
"More oddly, the switch and all three wires are not energized when it is on and providing power, but shows current when it is off. Huh?"
EXACTLY what does that mean.
What use used to make the measurements and exactly how where they done.
What wires and cables are in that box and how are they connected.
All applications for a SPDT switch are not for use as 3-way switches. They can be used to select one of 2 options. Examples are for a 2 speed fan and an outdoor light that can be swtiched to automatic (photocell or timer) or manually on.
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
You've written a couple of times that there is no current when the switch is ON, but there is when the switch is OFF.
When you write ON do you mean the switch is in the "up" position, and OFF it's in the "down" position? Remember, if this is a 3-way, ON/OFF and up/down are only relative depending on the orientation of the other switch.
Actually, what I mean to say is that the fixtures and receptacles are energized but the 3-way itself has no current flowing through any of the three wires. When the switch is flipped the lights etc. go off and at least one of the wires in the switch becomes energized. Crazy?
You mean no voltage registers, I suspect. Unless you have a clamp-on ammeter you can't measure current.
It is an ironic habit of human beings to run faster when we have lost our way. --Rollo May
Right, no voltage detected with a reliable non-contact tester. I had no voltage detected with the wires disconnected and using a multimeter.
Dont know but i did wire a 3 way that did not work .
I had an electrician come over and look at it.
I had wired it correctly but the switch was bad