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Mike, Master Electrician
Category: Electrical
Satisfied Customers: 2742
Experience:  Licensed Master Electrician - OnQ Certified Data Voice Audio Video Installer
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I want to add a new light and switch to an existing switch

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I want to add a new light and switch to an existing switch box. The existing switch doesn't look to be in line with the power source but at the end of the line (one black wire, one white wire and a ground) rather than black into the switch and black out again with the neutral passing through. How do I get power to the new switch and lights?
How are the wires connected to the switch? How are the wires from the currently installed light fixture connected to the wires in the box?

Edited by Mike Pettinato on 11/23/2009 at 5:30 PM EST
Customer: replied 6 years ago.
one white wire and one black wire, each connected to one of the terminal posts on the switch.
Great... that confirms that you don't have a neutral in this box and will need to jump power from the light box or another location. Assuming you would like to get power from the light fixture junction box, I will need to know how the wires are connected in that box.
Customer: replied 6 years ago.
I don't know how it is wired at the junction box. I haven't opened it. what should I look for when I do?
Just tell me how the wires are connected. You should have at least two cables coming into the box (each cable consisting of one black and one white - disregard grounds for now), maybe more, I'll need to know how they are connected to each other and what color wires the light fixture wires are connected to.

Edited by Mike Pettinato on 11/23/2009 at 6:37 PM EST
Customer: replied 6 years ago.
I'm not at home. I have my husband looking and will let you know shortly.
Customer: replied 6 years ago.
ok, the current switch runs lights. coming in to the box is 1 white wire and one red wire. the white wire is conneced to the 2 white wires coming from the fixtures. the red wire is connected to 2 white wires and one black wire headed to the switch. the 2 black wires from the fixtures are hooked together and to 1 black wire going to the switch.
Ok... can you try explaining it without explaining where the wires are going, I'm having trouble following your explanation. Can you just tell me how many wires you have coming into the box and how they are grouped together? You should have insulated cables that have mulitiple wires coming out of them. Is this not the case?
Customer: replied 6 years ago.

coming in there is 1 insulated cable with a red and white wire. everything else is individual wires.


white wire in connected to 2 white wires (one from each fixture)


red wire in connected to 2 white wires and 1 black (that go back out of the box)


2 black wires on the fixtures are connected together with one additional black wire (that goes back out of the box)

Ok great, it appears that the red wire in the box is "power" and the white wires that the light fixture white wires are connected to is "neutral". These are the wires that you'll want to tap into to get power at your new fixture. You'll need 14/2 (if this is a 15amp circuit) or 12/2 (if this is a 20amp) circuit. This cable will have a black and a white wire plus a ground. Black connects to the bundle with the red wire and white connects to the same white wire the light fixtures are connected to. You'll run this cable to your new light fixture box. Then run another cable from this light fixture box to your switch. At your switch you simply connect white to one screw, black to the other screw, and then your ground to the green ground screw. At the light box you connect the black wire to the white wire going to your new switch. This leaves one black and one white wire, which connect to your light fixture, black to black and white to white

Customer: replied 6 years ago.

can I run the power to the switch first and then to the fixture?


Sure, if that is an easier run for you, you absolutely can. In that case you would just connect the white wires together in your new switch box and secure them with a wire nut. That would leave you with the two black wires which both connect to the switch, one to one screw, the other wire to the other screw. Then at your light fixture, connect black to black, white to white, and ground to ground. As you can see, this is the more straight forward method and is desirable if it's not overly difficult to run a wire to your switch and then from the switch to the light fixture.

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