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 half.italian 12-29-2009 02:13 PM

adding switch and light at end of circuit

Hi!

I never realized how confusing wiring could be until now. :\

I am trying to add an outside light with a switch controlling it to an existing circuit. The way it is currently wired, I think the current switch is at the end of the circuit. There are three wires coming into the switch box (black, red, white). Black and red show 120 volts, and black and white show 120 volts.

I have run a new 14/2 wire into the switch box from the new light. How can I wire the switches so that they each switch one light?

I think I could do it if the power was coming into the switch first, but this setup has had me confused for two days!

~Sean

 JoeD 12-29-2009 08:20 PM

How were the wires connected in the old switch box? Is the existing switch one of a pair that control a light?

You might not be able to do it.

 half.italian 12-30-2009 10:35 AM

I don't remember how they were connected, but I can get the current switch to work by connecting up red and black to it, or (I think) by connecting up white and black to it.

They are individual switches, and yes I planned to use two of them in a double gang switch box to control both lights.

Since both red and black are hot, I was thinking I could power the second light from red, but I couldn't figure out how to complete the circuit. Then again...maybe red is a second neutral since black and red complete a circuit...im confused!

~Sean

 kok328 12-30-2009 10:39 AM

Sounds like you opened a two-way switch.

 half.italian 12-30-2009 10:43 AM

Quote:
 Sounds like you opened a two-way switch.
What does that mean? Is it good or bad?

 JoeD 12-30-2009 11:20 AM

Are there only three wires in the box?
Were they all conencted to the old switch?
Was there more than one switch contolling the old light? Could you turn the old light off from two differnt locations?

 half.italian 12-30-2009 11:36 AM

There are only three wires coming into the box. Plus the two I just ran.

The house is old, and I bought it about six months ago. I haven't found any other switch that controls the light... I'm pretty sure it can only be controlled from this switch. It's actually a fan/light combo if that makes a difference.

I think only the black and white were connected to the last switch, and the red was capped... not positive though.

Thanks both of you for your help so far.

 JoeD 12-30-2009 01:47 PM

Sounds like it was setup so that a fan and light could be controlled separately.

You may need to make some changes in the fixture. Please open the fixture and tell us all the wire connections. Do not change anything at the fixture at this point.

 half.italian 12-30-2009 03:59 PM

LOL... I think this added another layer of complexity to the situation. At the fixture there are only two wires coming in (black and white) and they are not of the same gauge that I am getting at the switch. These two wires must go to another junction box (located above the fixture)

In the fixture, blue (motor) and black (lamp) go to the black from the source, and white goes to the white from the source.

I guess I need to go to the junction box and see if I can isolate the connections from there down to the switch now! I probably wont check today, but will post back with what I find when I do.

I see a glimmer of hope. :) Thanks.

~Sean

 half.italian 01-02-2010 03:57 PM

Just wanted to report back. I finally got it to work. I don't really understand how it works, but it works.

I had to go to the junction box above the fixture, and rewire some connections. I had to make two main changes there. 1. Disconnect the red wire going to the switch from another red wire going to an unused outlet. Then connect the black wire from the light to the red wire going to the switch. 2. Add white from source to the (already connected) white from the light and white wire to switch.

Once that was done, the switch wiring fell into place. Very confusing, but I ended up learning a lot.

I found these great diagrams that finally made sense to me... check them out!

How To Wire a Switch - Light then Switch then Outlet