Friday, July 30, 2010

Changing light switch with plug to just light switch

Three light switches with exposed wiringImage via Wikipedia
Question:

In the bedroom the main light switch also had a plug.plug cover broke off.Want to put just a light switch.But in the box there are four black wires,four white,and 4 ground.One goes to the light mounted on the wall which has a turn knob.and two hanging lights on each side of the room.How do I know which black and white to hook to the switch to make it work.I beleive I'll have to cap a white and a black wire to eliminate plug wires but what do I do.

Answer

Hi Alexia,

I will do my best to help you here. This is a good project for a beginner. You should be proud of yourself for taking this on but if you don't feel comfortable it is OK to call an electrician. Better safe than sorry.

OK Here we go.

First, tie all your ground wires together. Put them under one wirenut and use a 6inch scrap ground wire to jump out of the wire nut to attach to the switch.

Second, place all the white wires under one wire nut. Since you will not be using the outlet you will not need to attach any white wires to the switch. In this situation the white wires are being used as the return path for the electricity or you neutral. Push all the white wires to the back of the box.

Third, Put all the black wire together. Turn the power on. The light should go on. Now remove one wire at a time until the light goes off. When you find the wire that controls the light tie the other three wires together and use a scrap wire as a jumper. Put the jumper on one side of the switch and the wire that controls the light on the other. When the switch closes the light will go on an when the switch open the light will go off.

That is all there is to it.


Good luck


--
Bill Lutz
Generation 3 Electric, Inc.
http://generation3electric.com
http://www.philadelphia-electricians-how-to.com/

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2 comments:

  1. Hi, as an electrician, I'm afraid I have to take issue with this answer. First of all, you don't know that there's only one circuit going into that box. If there's more than one, you've just instructed a homeowner to tie two circuits together, and not just the neutrals, but also the hots, which will pop their breakers (and hopefully only do that).

    Probably you only have one circuit with one incoming hot, but then you probably also have one outgoing hot to the light on the wall which sounds like it is not controlled by the switch, but by its own switch. You can't even be certain about that though, since it wasn't specified whether that light switch also controls that switch.

    I'm all for people learning new things and taking care of their homes, but this advice is too simple for the situation. You might get lucky and it might work just as you said, but having seen so many houses wired so many different ways, the chances of that are not especially great. A newer house is probably wired as you described, and older house, probably not.

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  2. @Anonymous,

    You do make some good points. The advice here is just general advice and is only meant to answer the most common scenarios.
    I all way recommend that homeowners contact a qualified electrician before they get in over their head.

    ReplyDelete