Diagnosing problem with 3-way switches
 

A light fixture in a 3-way circuit stopped working.

I have (3) 14/2 feeds coming into the light fixture, which I assume to
be power, switch-1 and switch-2. I have not touched the 3-way
switches.

However I am getting only 60v on the power feed. I am getting 120v
when I check between 2 different feeds. When I flip one of the 3-way
switches, I get 30v on the power feed.

The wiring is 55 year old BX (armoured). I had some loss of insulation
on the feeds inside the box from the heat of the fixture. When I bent
the wires out of the box, it started to crumble off.

When I turn off the power and check the resistance of the switch feeds,
only 1 of them goes to 0 ohms when I flip the switch. The other always
appears open with infinite resistance.

I was hoping to avoid running new wiring, but it sounds like I might
have a short outside the light fixture box. Should I start by
replacing the 3-way switches?

Any other advice/recommendations appreciated.

If the insulation is crumbling you must remove the box and cut back the
armor a few inches on the cables or replace them. As far as you original
problem, the first thing that you have to do is identify each cable. You say
you have three- two wire cables in the lighting box- That means you have a
feed coming in, a feed going out to something else, and a pair of switch
legs going to one of your three way switches. If you open your two switch
boxes, you should find one - three wire cable at one and both a three wire
and two wire at the other. Once you've got it all exposed and identified,
someone here can talk you through reconnecting it
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A light fixture in a 3-way circuit stopped working.

I have (3) 14/2 feeds coming into the light fixture, which I assume to
be power, switch-1 and switch-2. I have not touched the 3-way
switches.

However I am getting only 60v on the power feed. I am getting 120v
when I check between 2 different feeds. When I flip one of the 3-way
switches, I get 30v on the power feed.

The wiring is 55 year old BX (armoured). I had some loss of insulation
on the feeds inside the box from the heat of the fixture. When I bent
the wires out of the box, it started to crumble off.

When I turn off the power and check the resistance of the switch feeds,
only 1 of them goes to 0 ohms when I flip the switch. The other always
appears open with infinite resistance.

I was hoping to avoid running new wiring, but it sounds like I might
have a short outside the light fixture box. Should I start by
replacing the 3-way switches?

Any other advice/recommendations appreciated.

Do an internet search for a schematic of a three-way switch circuit and
the problem should be obvious if the original wiring used the proper
color code.

How hard is it going to be to replace the wiring? Crumbling insulation
sounds bad.