Latest Discussions : Electrical & Lighting


10:18AM | 12/24/06
Member Since: 12/23/06
2 lifetime posts
I am trying to replace my dimmer switch. I have a light at the bottom of the stairs with an on/off switch next to it. I also have a switch at the top of the stairs with a dimmer on it. Inside the box I have two black wires tied together. I also have two white wires tied together. I have a single white wire by itself. The switch i have has a black lug and ground connect on one side, an on the other side I have two brass lugs. I have blown two switchs trying to figure this out. Evey example I have looked at talk about red wires, I have none. Some say that I have to have a 3 way switch on both sides. It was working fine until I tried to replace the dimmer switch. Got any ideas?

Tom O

03:29AM | 12/26/06
Member Since: 09/17/02
476 lifetime posts
If both switch locations control the same light, then you likely have a wiring installation that does not comply with the National Electrical Code. I have seen some installations with two 2 conductor cables rather than one 3 conductor cable between the three way switches. The NEC requires all conductors of the same circuit to be in the same cable.

You would need two three way switches or a three way switch and a three way dimmer to make this work if the proper wires are available.

You may want to consider hiring an electrician to straighten this out.


05:06AM | 12/26/06
Member Since: 09/17/02
524 lifetime posts
Yes you must have a three way at both ends. I am confused as to what you are attempting to do. Are you changing the dimmer or the switch or both? Can you put back what was there before and make it work?

You need a three way dimmer and a three way switch. The black screw is the common screw. The wire connected to the switch are the only one you need to deal with. DO NOT change any of the other wires in the boxes.


05:57AM | 12/28/06
Member Since: 12/27/06
14 lifetime posts
Generally yes, 3-way switches use a Red, Black and White wire that's included in a 14-3 cable, but really all you need is 3 wires, it's possible to use 2 14-2 cables and just use 3 of the wires in the circuit, and not using the 4th, that's proably why you don't have a red wire in your box.

Wiring can be very simple or very complicated depending on who wired it. Without a tester, there's really no way be me to explain to you how it install your switch. I would need to know which wires have voltage, which are neutral if any (just becuase the wire is white, doesn't make it a neutral wire) than you would have to flip the switch at the other end and see what changed, if anything.

Ideally if you were just replacing a switch, you should have wired the replacement exactly like the old one was. At this point I would suggest an electrician.

Tom O

06:34AM | 12/28/06
Member Since: 09/17/02
476 lifetime posts
I may have made a mistake in assuming that your wiring system is a cable wiring method. If you have a conduit system, then it could be very possible that you don't have a red wire.

What do you mean by two black wires (and two white wires) tied together? Do they just splice together and don't go to the switch?

As suggested by Techgromit, it is possible to wire a 3 way switch with a pair of two wire cables, but as I stated in my first reply, this installation method would be a code violation.


07:01AM | 12/28/06
Member Since: 04/25/05
1915 lifetime posts
"but really all you need is 3 wires, it's possible to use 2 14-2 cables and just use 3 of the wires in the circuit, and not using the 4th,"

While it will work using two cables does not meet code.

One of the basic requirements is each cable or each conduit is that the NET current should be zero. That is current in the supply line(s) should equal those in the return line(s).


10:41PM | 12/28/06
Member Since: 12/23/06
2 lifetime posts
Thank you for your input, an yes I need a electrician. Techgromit pretty much hit the nail on the head. I think he figured out that I am from the hills of the Midwest where doing things by code is just a suggestion. Where lugging wires together right outside the breaker box is not even a concern to the state inspector.

Thanks Again


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