3 way electrial wall switch question
The downstairs switch works as expected.
If the upstairs switch is then used to turn the
light off, the downstairs switch does not work.
Is the problem with the switch or is it wired wrong?
I have the exact probelm right now ! I've had it be both the wiring
and the switch. Easiest check is - Turn the power off and loosen the
switches so you can check how they're wired. If they look correct
(check vs. a wiring chart), check the wiring at the light that they
control. There's multiple ways to wire 3-ways, one way has all the
connections at the lighting fixture's electrical box. Basically take
it all apart and put it back together correctly with all the
connections tight, etc.
If everything looks ok, I'd replace one switch, check it, and if still
messed up, then replace the other. This happened to me once where the
switch itself was broken, that was fun. If they still don't work,
panic, cause I'm out of answers and it could be a wiring problem.
There can be junctions along the way, etc. It's not some weird flaw in
the wire itself, it's either a switch or a connection.
You can check a three-way switch with an ohm meter. Turn off the electric
and disconnect the switch from the wires. Normally there is one terminal
that's a different color than the other two terminals. Put one ohm meter
wire on the different color terminal and one on either of the two same
colored terminals. Flip the switch, and the meter should change. Do this for
the other same colored terminal. If the same thing happens, then the switch
Never connect an ohmeter until you have first connected a voltmeter.
Even if you've turned the electric off, because eventually you will
skip turning it off for one reason or another. (A common reason is
that you forget. Or you've already turned it off and on a couple
times and you're tired of going to the basement. Or you lose track.
Or you will think you turned off the right breaker, but you'll get the
wrong one. )
Especially with 110 volts or more. With 9 volts, I don't think youll
burn out the ohmmeter, but you'll get into a bad habit.
Remove NOPSAM to email me. Please let
me know if you have posted also.
Well, fully armed with all the good information, I had at it. The
house is about 50 yrs old with original wiring. I unscrewed the fuse,
pulled the switch cover plate on the upstairs switch. I tested with
the ohm meter and it tested ok with wires attached. I tested the 1st
floor switch and it tested bad. So I replaced the switch and wired
same as I found it after ohm testing the new switch. Still tested bad.
Being from Kansas, I refused and switches worked as original. I
unfused and pulled the switch out for closer look. Being so old the
three wires looked the same color. I got a real bright light and
determined one was slightly different than the other two and connected
to a common terminal. Someone had wired it to the common termial years
ago. I reversed the two so the same ones were on the common terminals.
Then checked with olm meter and everthing looked ok. So I turned the
fuse back in and IT WORKED AS ADVERTISED.
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