Wall Light Sconce - Simple project?!

I am trying to install a wall sconce at the top of my (too dark) basement stairs. Conveniently, two feet below the where I want the fixture is a switch controlling a single light in the basement. What I think makes sense is to merge the new fixture into this switch box so that one switch lights up the top and bottom of the basement.

What makes me nervous is I can’t find an example of this in my electrical wiring book, or in the three I browsed at the town library, or in the two I found at Home Depot. It seems pretty common to have one switch control two fixtures.

The Home Depot guy sold me 3+ feet of wire (the white cable, three-in-one stuff, rated 15) and a box. The “box’ he suggested was circular blue plastic baby with screws that operate plastic clamps that are supposed to be The Right Thing when you’re dealing with plaster/lathe and no stud. Well I cut the circular hole but there wasn’t enough depth for the box. The stud here is sideways leaving less than two inches. Home depot doesn’t have a shallower box to fit the hole I now have in my wall.

But I digress, ‘cause I suspect I can find a solution to the fixture box. What worries me is the basic wiring. Leading to the switch box is a conduit with three wires, they are wrapped in a 1930’s fabric-like covering, but I think I can deal with that.

Is this what I do?

0. Turn the power off.

1. In the switch box, disconnect the wires to the switch and straighten the wires.

2. Cut off a five-inch section of wire and spit into the three wires: white, black and ground.

3. Feed remaining ~30” section of 3-in-1 cable/wire from the fixture box hole to the switch box.

4. Twist together the two black wires with the existing hot wire and cap the 3 wires. Do the same to the 3 white and 3 ground wires.

5. Tape over the old wire coverings.

6. Shape into a hook the ends of the 5” sections of white, black and ground wires and screw onto the switch.

7. Find and install a fixture “box” that fits.

8. In the fixture box, trim back the cable’s plastic coating to expose ~3” lengths of white, black and ground wires. Expose 3/4" sections of each wire.

9. Twist the black wire that comes from the switch box to the black wire from the fixture and cap. Do the same thing to the white and ground wires. Tape.

10. Clamp or staple or affix the cable in the fixture box and the switch box.

11. Turn on the power and watch the fuse blow. Replace the fuse only to have the new fuse blow. Call an electrician.

Do I have this about right?

Thanks in advance,
Bob

 

In a word, "no".

You may or may not be able to do your project from the existinging switch at all. I suspect that you can, but I don;t know for sure. I am having a hard time understanding your proposed instructions, but they are wrong.

What we need to know is a complete invgentory of ALL the cables in the existing switch box. Be specific. Describe each cable and then tell us where the wires from the cable are connected. Include all cables.

it does sound like you have the wiring correct for the new light, once you find the proper box. And it sounds like you may have to install a box and then repair the wall, but that is a separate issue.

 

You are wiser than most people in that you asked before just doing it. As Bob says, most likely your plan is incorrect.

I think you may have already answered most of Bob's question. You said that the switch box has three wires. Do these wires have colors? Is the switch a standard single-pole switch (says "on" and "off" on the lever), or is it a 3-way switch with another switch at the bottom of the stairs.

 

The switch box has one "cable" and three copper wires, all attached to the switch. One wire connects to the top right of the switch, one to the top left and one to the ground. None of the wires are colored (or if they were 65 years ago it has faded).

It is a standard on-off switch but---and I didn't realize this until you asked---there is another switch in the basement that controls the basement light.

Thanks much guys.

 

Your best bet, if you can, is to run a cable from the existing light to the location of your new light. I realize that this is harder than running the new cable to the switch, but, unlike your original plan, this would actually work. Remember, drywall repair can be fun.

 

What you have are two three way switches. 3 way switches allow a light to be controlled from more than one location. You cannot add a light to this setup and connect it to the switch at the top of the stairs.

The solution, as John said, is to run a cable from the existing light to the new light.

By the way, your terminology is not correct. Your switch is not grounded. None of those three wires are a ground wire. They are all hot wires. One is a common and the other two are travellers. They are all current carrying wires at one point in the switch cycle.

 

... so that's why I couldn't find an example in the books.

I think I'll just return the fixture and patch the hole I made. There's no way I can run a cable between the lights, not and do it right.

Plenty of other projects await!

But thanks guys!