3-way circuit trips breaker

Thread Starter

LV Bob

Joined Jan 22, 2007
I have a problem that just surfaced. There is a 3 way switch that controls in-ceiling can lights. (Also on the breaker circuit but not controlled by switches are wall four outlets). The two light switches are both 3-way dimmers. They were installed last May. This week, the circuit breaker tripped. I could not re-set it so I unplugged everything and through process of elimination found that when I flip one of the light switches, it trips the breaker (the other light switch functions and the breaker doesn't trip as long as the "bad switch" if off). I replaced the 3 way with just a 3-way (not a dimmer) and the problem still exists. Any ideas on why it would do this after 9 months??


Joined Jan 21, 2007
Hello LV Bob,

If your circuit is wired like the attachment, then you have a short circuit to ground or neutral in either wire #1 or wire #2.

When SW1 is switched away from the shorted wire, the light works OK.



Joined Nov 1, 2006
Pull both switches out of the wall and try it again; it's possible you have a ground wire touching a terminal on the "good" switch which causes a short when the "bad" switch is thrown so as to try to energize the grounded wire. If it's not that it's possible you have a staple or nail through your romex [wiring]. Give that a try then let us know if you still have a problem.