Here's the situation... I have one light switch that controls two separate lights.
Outside post light
Outside porch light
I would like to install a new box/light switch so that I can turn the outside porch light independently. Any idea how I can tell which wires go to what? I have an electrical tester (measures voltage, ohms, etc.). Please let me know how I should go about this.
You're probably going to end up pulling wires. I am guessing once you dig into your wiring that you will find that the wires go switch to porch light to post light. thus there is no way of doing what you propose without additional wires.
The only way to determine this is to pull down the porch light and open up the electrical box that holds the switch, and see what is inside. Unless you are very comfortable working with electrical devices, you probably want to switch off the breaker before starting.
If you open the switch box and find only one set of wires attached to that switch, you need to find the junction where the wires from the post and wires from the porch light come together. Possibly at the porch light, but if there is basement or crawlspace under this switch location, the wires to the post may be found there. I would expect you can find where the wires leave the house to go underground to the post fixture, and work backwards from there
Unfortunately the person that wired these lights ran two hot and two neutral wires to the same light switch. This should make it easier to repair, but determining which wires go where is my problem. I don't want to cross hots or neutrals and have more of a hazard then I already have. :)
Actually, that's good. Just separate the two "load" wires off of the switch and get a duplex switch. The hot (feed) wire goes on the line side of the switch and the two "load" wires go to the other side, and you've got independent switching of both fixtures
Does the present switch have one hot wire coming in on one side of the switch and two --one for each light--on the other side of the switch? If so, just disconnect one and see which light quits working. If the setup is not like that, you will have to give more specific details of exactly what you have. Also, they make a double switch that can replace the one you have (it takes the same cover as a standard wall plug) They are not cheap, at least compared to a standard switch, but the work saved will be more than worth the expense. Good luck Larry
First off, never open anything electrical up without turing the breaker off, at least if you can. if you can't be EXTRA careful. Secondly, you need to say what the wiring to the lights is. Is it conduit? Is there any connections to the lights other than from the switch? probably, the best way to do the job is to replace the wiring completely.
Your latest response troubles me. Don't take this wrong way, but are you sure that the wires to the switch are hots and neutrals or is it possible that you are confused by the colors? (I have no idea of the level of your electrical experience or what your switch wiring really looks like, so don't take this as an insult.)
Switches are not wired with hots and neutrals. Properly wired switches only break the hot wire. Many times a length of Romex is run back from the fixture to the switch and since 2 wire Romex only has black and white (plus ground) wires, the white is used as a hot. This is perfectly acceptable by code. The white should be marked with a black marker or tape to indicate that it is hot, but many times that is not done.
The picture at this site shows what I mean:
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What it sounds like is that you have is a length of Romex from each fixture at the switch. This makes the conversion easy.
Shut off the breaker, remove one back and one white wire from the switch, making sure they come from the same piece of Romex. Hook these to a new switch and you have separated your fixtures.
If you want verify that this is how your lamps are wired, open up each fixture and you should see two lengths of Romex coming into the fixture. The black from one will be wire-nutted to the black (or white) of the other as shown in the picture at
Your latest response troubles me. Don't take this wrong way, but are you sure that the wires to the switch are hots and neutrals or is it possible that you are confused by the colors? (I have no idea of the level of your electrical experience or what your switch wiring really looks like, so don't take this as an insult.)
Switches are not wired with hots and neutrals. Properly wired switches only break the hot wire. Many times a length of Romex is run back from the fixture to the switch and since 2 wire Romex only has black and white (plus ground) wires, the white is used as a hot. This is perfectly acceptable by code. The white should be marked with a black marker or tape to indicate that it is hot, but many times that is not done.
The picture at this site shows what I mean:
formatting link
What it sounds like is that you have is a length of Romex from each fixture at the switch. This makes the conversion easy.
Shut off the breaker, remove one black and one white wire from the switch, making sure they come from the same piece of Romex. Hook these to a new switch and you have separated your fixtures.
If you want verify that this is how your lamps are wired, open up each fixture and you should see two lengths of Romex coming into the fixture. The black from one will be wire-nutted to the black (or white) of the other as shown in the picture at
Ok, I think that solves my wiring problem. Thanks for the help.
Now the issue is I have a 2 gang box, in which both are in use (I have one interior light on that same gang too). Can you point me to one of those switches that will work two lights off of a one gang installation?
Sure, if you are using "regular" wiring devices you can get two switches on a frame that will fit behind a duplex receptacle cover plate opening, if you are using "decora" style devices you can get either two or three switches on a frame that will fit behind one decora/GFCI cover plate opening. All of this can be found at Lowe's etc. in your choice of several colors (white, ivory, brown, etc.)
PS - all the neutrals should simply be spliced together with a wire nut anyway so don't worry too much about them. likewise with the grounds if present.
The switch set-up shown here is what you want. The 2 horizontal switches are one unit and are designed to use a standard "single toggle-duplex receptacle" switchplate.
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If your local home center doesn't have them, any decent electrical supply house will.
I have a setup like this > Ok, I think that solves my wiring problem. Thanks for the help. >
I just bought one of those dual-switches at Lowe's. It's one that fits the same cover plate as a standard receptacle. They have them in decora style too.
"Unfortunately the person that wired these lights ran two hot and two neutral wires to the same light switch."
If what he called the "neutral" is actually attached to the switch, then the odds are that it is not a neutral. Odds are it's the hot lead to the fixture as shown this site:
[I read further and I gather from the rest of the thread that he has enough wires (but since it's written, I'm still going to post this) but if he didn't...]
Well, there is still the possibility of X-10. I don't like to use that, but if sufficiently pushed I would. Especially say if I were moving in a couple years and didn't want to run wires, or if I didn't know how to pull wires. It would probably also make the bulb too high in the fixture, but there might be a different device other than the obvious that would get around that.
It took me about 15 minutes or so to isolate the power source, as there were many splices in it. Apparently it feeds a few nearby outlets. Anyway, after I found the power source I installed the duplex light switch that fit perfectly. Both lights now work on separate switches!
Now I have a happy wife that can turn on the outside pole light and be like the rest of the neighbors on our street. My wallet may not like the extra electric usage, but a happy wife is priceless!
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