Need help replacing switches in four-way circuit

magnolia

I am trying to replace the switches in a four-way circuit (three switches, one light). (There is nothing wrong with the switches, we just want to update them.) The switches are old (about 1960) and do not have anything to distinguish the common wire from the others (no label, all screws are the same color, etc), I have replaced single-pole switches before, but this is my first time tackling three/four-way switches. Can you help me figure out which wire goes where? For what it's worth, one three-way switch has a black wire, a white wire and a red wire, the other three-way switch has two black wires and a white wire, and the four-way switch in the middle has two black and two white. But considering how strangely this house was wired, that might not mean much. The voltage across the various wire is either 70 V (is that normal??? Shouldn't it be 120 V like the single-pole switches?) or zero V. But I'm not sure how to tell from that which wire is the common. Thanks for the help!

mr500

From where is the power feeding from the panel into the circuit? 1st switch? 2nd? 3rd? is it going to the light first then the switch?

Also is it 2 3 ways and 1 4 way? Check this link. Might help

http://www.wakeforest.edu/~matthews/...itchesTut.html

http://www.selfhelpandmore.com/switchoutlet/4way/

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__________________
Im Not An Electrician...But I Did Stay At A Holiday Inn Express Last Night!!

joed

Replace one three way switch. Take a guess which wire goes on the common. The new switch will be marked. Try every switch and see if it works. If it doesn't work, move a different wire to the common. It will only take three tries. After you get one working try the other three way. If you can remember which terminal the common wire was on for the first switch it would be a good guess that the wire in the same position on the other switch is the common. When that is working then the tackle the four way. Most likely the black and wire from one cable are one set and the black and white from the other cable are the second set.

magnolia

Thanks, joed. Good idea -- I'll give that a try.

mr500 -- Thanks for the diagrams. That helps explain it. I don't know which switch the power is feeding in to. I'm finding that all the electrical stuff in this house is pretty nonstandard (9 wires to operate a doorbell??). Yes, it's got two 3-way switches and 1 4-way switch.