I recently moved into a new house and found a pair of 3-way switches
controlling a hallway light from 2 locations that when one switch is off
the other switch doesn't work and vice versa. The wiring doesn't
resemble anything I've seen before for wiring these types of switches.
Can someone help me straighten this out?
Wires from the Circuit Breaker to First Switch
White --> Spliced to Red on the set of wires going to the second switch
Black -- > Double Screw Side (brass)
Wires from First Switch to Second Switch:
Double Screw Side (black screw) via white wire to Single Screw side
Single Screw Side (brass screw) via black wire to Double Screw side
Circuit Breaker White spliced to red wire and attached to Double
Screw side black screw
Can't help you from what info is provided. Bottom line is that for it
to work, there must be 1 wire going from each switches' brass screw, to
the brass screw on the other switch; so that you have 2 wires running
between the switches.
These are called 'travellers', and it doesn't matter which brass screw
on one switch is hooked to which brass screw on the other switch.
Now you are left with 2 black screws, 1 on each switch. One black screw
gets hooked to hot, and the other black screw gets hooked to the light.
Finally, somewhere in either of the 2 switch boxes, or the ceiling box,
the light will get fed it's neutral. It all depends on how the wiring
Your best bet is to first identify your incoming hot/neutral, and work
My mother-in-law has this same problem and after reading your reply, I think
you may have the answer I need. I would like to verify with you how to ID
the wires asuming the switches were wired wrong originally and the previous
owner didn't use standard color codes. I assume I can ID the wires using a
simple 2 probe tester with LED. The hot wire should be the only wire to
light the tester with one probe on hot and one probe on ground. One probe
on hot and one probe on neutral should also light the tester.
So here is my idea . . .
1) Turn off circuit breaker. Disconnect both switches and spread the wires.
2) Turn on CBreaker. Without touching a wire with a bare hand, ID hot wire
using method above.
3) ID the neutral wire. Since the traveler wires do not complete a circuit
with the switches removed, the neutral is the only wire besides ground that
should light the tester when the other probe is on the hot wire.
4) The remaining 2 wires should be the travelers.
Did I mess anything up or forget anything?
Any help on this is greatly appreciated.
Thanks in advance,
Your procedure should work. Just print out and follow the diagram from the
site I posted earlier.
Note that the switching is done on the hot line. If properly wired there is
no neutral in the switch box. The white (neutral) is attached only to the
lamp. I expect you will have to use ground for making your measurements.
In the diagram the white in the first switch is hot, as it is junctioned to
the black hot line at the lamp.
Just a warning, not all 3ways have different collored screws. So look
for the word "common" imprinted on the body by the terminal. Infact,
reguardless of whether colored screws or not, do this. Don't want to
be messed up by someone 'screwing' around. :-P
I have had this happen before. If it was wired correctly originally, then
one of the swiches has become defective (perhaps a low amp rating or an
overseas brand). Given the low cost of switches, the easy solution is to
turn off the breaker and replace both switches. When you go to the store
make sure you tell them you need to control one light from two switches.
If this doesn't work, write back and I will attempt to help you with what
then would be a more complicated problem.
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