Possibly the hardest part of installing a new outlet or switch is running the new wires through the walls. This job is often frustrating because you cannot look into the wall to guide the wires. Frequently obstructions within the cavity, like fire stops, will block your attempts to run a wire from one location to another.
Like most jobs, this one can be made easier if you have the right tools on hand. You’ll need a “fish tape,”–a spool of tempered steel spring (fish tapes are also made of polyethylene) about one-fourth-inch wide. The tape is flexible enough to bend around corners, yet still stiff enough so you can push it through insulation to the floor above.
Most fish tapes have a hook on the end. If your model is flat, or if you should accidentally break the hook off, you can fashion a new hook. Because the tape is made of tempered steel, you’ll first have to heat the end until it glows red. This will remove the temper so you can bend it into a hook.
For long wire runs in tight spaces, you might want to purchase a can of wire-pulling lubricant. This is a creamy compound with a wax base, available in aerosol cans or in paste form. The lubricant clings to the wires so they can slip through insulation, narrow orifices and conduit.
Another handy tool is a length of chain about 6 to 8 feet long. One end of the chain can be dropped inside the wall to an opening below, where you can pull it out and attach the electrical wire. The chain works well because it has no sharp edges that will hang up on the inside of the wall.
Another useful tool is the common wire coat hanger. It can be made into a tool for catching the chain, fish tape or wires. Straighten it into a long rod, then bend the end into a hook.
When joining the electrical wire to the end of the chain or fish tape, it is essential to wrap the joint with electrical tape. This will keep the pieces from separating and will also provide a smooth surface so the wires don’t catch on anything within the wall.
You will also need a keyhole, or wall board, saw; a utility knife; an electric drill with a three-quarter-inch spade bit, and, perhaps, a hammer and chisel. These tools are necessary to cut openings in the wall for outlet or junction boxes and to drill holes for the wires to pass through. A ruler, flexible steel tape and a plumb bob will also be useful for measuring and aligning the openings.
In most cases, the easiest wire run is between two openings in the same wall cavity. To make the run, cut the outlet openings so they are vertically aligned. Anchor one end of the chain at the top hole so it doesn’t fall into the cavity, then drop the other end through the hole until you can see it through the lower opening. Grab the end and attach the wire, then pull the chain and wire up through the top opening.
Sometimes the chain will not drop down, but will meet a barrier. In most cases this will be a fire stop–a length of 2-by-4 that spans the studs. To get around it, you’ll first have to mark its location. Drop the chain through the top hole until it stops. Mark the chain at the opening then pull it out.
The length from the mark to the end of the chain is the distance from the opening to the obstruction. Transfer this measurement to the wall and cut a 3 by 5-inch hole to expose the fire stop. Use a chisel to cut a notch about one-inch wide in the fire stop. Now you can pull the wire to the top hole past the fire stop. Cover the notch and the wire with a metal plate and patch the hole with a piece of wallboard.
Pulling a wire between floors can be difficult because the wall plates across the studs enclose the wall cavities. You’ll need to drill a hole through the plates before you can run the wires. If you’re making a basement hookup, such as running a wire to the service panel in the basement to an exterior wall, you can easily find the wall plates at the end of the floor joists.
The working space is apt to be tight, so you’ll have to hold the drill at an angle to bore the hole. Work carefully so the bit doesn’t penetrate the outside wall. Once you’ve bored the hole, you can push the fish tape up through the insulation to the outlet opening in the wall above.
When you are sure that you’ve located the wall, drill through the subfloor and the wall plate into the wall cavity. Then it’s only a matter of feeding the fish tape to the outlet hole above.
