So I'm replacing a 2 three way switches because one failed. Worth noting th e switches probably 60 years old. I disconnected them and reattached in the same way and only one switch works. I disconnected the switches and using a non contact volatile tester i discovered that there is a hot wire in both boxes when there should only be one between the two. I'm no electrician bu t I'm pretty good at wiring but this one has me stumped and I could use som e help on how to proceed. Thanks
one has me stumped and I could use some help on how to proceed. Thanks
Sometimes the non contact detectors will 'lie' to you. There can be enough voltge picked up off wires that are in parallel with each other to set them off.
Look at the old switches and compair them to the new ones. The actual screw terminals may be in the same physical place, but elecrically in different places.
Sounds like you just have the wires in the wrong places.
3-way switches drive me crazy. I think that is because, as your website link shows, there are many different ways that they can be wired. Sometimes the "feed" or power first goes to a switch, sometimes first to a fixture, or the fixture can be between the switches or before the switches or after the switches. I often see and hear people suggest one wiring solution and they say "that's how 3-way switches are wired". But, they often don't take into account that from a distance there is no way to know what the wiring pattern is on any particular location. And, since the wires are in the walls and/or ceiling etc. there is usually no easy way to figure out what the particular wiring pattern is.
I once saw an explanation online about how to figure out the actual wiring pattern once the 3-way switches are apart and the user can't figure out how to reconnect the wires. Unfortunately, I don't remember where I saw that. But, I think the trick (once the 3-way switches are already off) may have been to: 1)turn the power off; 2) disconnect ALL of the wires from both switches and any fixtures (lights?) that they control; 3) turn the power back on; 4) find the "hot" wire out of all of those -- and that is the "feed" or power to the circuit. Then, reconnect that wire and look for the next "hot" wire from there, and so on. It's hard to explain.
But, my point is that despite what I have seen others say or write about
3-way switches, there is no one right way to rewire them without knowing how the circuit is laid out.
Good possibility (even probable) the switch terminal location of the common isn't the same physical location on the new switch as the old; they're not even necessarily the same for new switches from different vendors.
The common will be marked distinctively from the carrier terminals; check vis a vis the removed one for "who's who in the zoo" and reconnect following function, not location on the switch body.
g the switches probably 60 years old. I disconnected them and reattached in the same way and only one switch works. I disconnected the switches and us ing a non contact volatile tester i discovered that there is a hot wire in both boxes when there should only be one between the two. I'm no electricia n but I'm pretty good at wiring but this
+1
Or get a tester that will measure actual voltage. If it's a high impedance one, he still might get some phantom voltage showing, but it won't be full 120V. Or temporarily jumper a lamp between the suspected hots and a neutral or ground to see if it lights.
Assuming he still knows which wire went where on the old switch. Another good question is how did he wind up with two switches replaced at the same time? Assuming it was still working, I would have replaced one at a time, limiting the scope of potential screw-ups.
I have one 3-way circuit where there are both hot and neutral connected to each switch. The light is connected between the common terminals. People call this unsafe (light may be hot when switched off) but it works.
The only one that is really unsafe is a corruption of the "coast" circuit that switches the neutral. It is used (illegally) because you can do it with 2 wires between 3 ways. The ones in that Wiki all look legal to me.
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