How to Rough-In Electrical Wiring (page 3 of 3)

Change Text Size

Change Text Size
|
Bookmark

Bookmark

Del.icio.us
Digg
Reddit
Facebook
StumbleUpon
TwitThis
|
Print
|
E-Mail

Connect the Wires

Complete the rough-in phase of the wiring job by connecting the appropriate wires with wire connectors, adding short lengths of wire (pigtails) where they’re needed and folding all the wires neatly into the boxes.

In addition, follow these guidelines:

When the circuit continues through a box, connect the wires and add pigtails. This method is easier and safer than connecting both sets of wires to the receptacle.
Leave one bare ground wire long, and snip the rest to 6 in. beyond the box. Push the long wire through the hole in the top of the special green wire connector and connect the remaining wires to it by twisting the connector clockwise until it’s tight. Fold the ground wires neatly into the back of the box.
Snip all the white neutral wires to the same length (6 in. beyond the box). Strip 1/2 to 3/4 in. of insulation from each wire and join them with the right size connector. The instructions on the connector packaging will list both the length of stripped wire required and the maximum number and size of wires the connector can safely join.
Identify the white wires you’ll be using as hot wires (with switches) by wrapping them with black electrical tape.
Organize the wires so you can understand them, and label them to avoid confusion. It’s much easier now than when the cables are covered by drywall. For labels, slide short scraps of plastic sheathing over the wires.
To keep track of three-way switch wires (two “travelers” and one common), twist the travelers together and wrap the common wire around them.
It’s good practice to cover the end of a hot wire with a wire connector. This helps to identify the wire later and allows you to safely energize the circuit if you need to.
Use cable stackers when you don’t have room to staple all the cables in the usual way.
Fold and tuck all the wires neatly into the box so they won’t be damaged during the drywall and taping process.
Neatly fold the wires into the box in this order: grounds, neutrals and then hots.

Before calling for a wiring rough-in inspection, look around to make sure you’ve installed enough cable staples and added nail plates where cables run too close to the face of a stud. Finally, to prevent air leakage, fill with expanding spray foam all of the holes through the top and bottom plates of the wall, and around exterior outlets and lights.

Skinny Walls

Protect the cable in 1-1/2 in. or thinner walls by running it through 1/2-in. metal conduit. Anchor a 4 x 4 x 1-1/2 in. metal junction box and attach a length of conduit to it with a conduit connector (you’ll need two conduits for two cables). Secure another conduit connector to the top of the conduit to protect the cable from the sharp edge of the pipe. Secure the conduit with a conduit strap. Attach the ground wire to the metal box with a ground screw driven into the threaded hole. Finally, cover the box with a plaster ring that matches the wall covering thickness.

Basic Supplies
For an average-size room, you’ll be able to buy all the electrical rough-in supplies you’ll need at hardware stores or home centers for less than $100.
Here’s what to buy:

Nonmetallic Cable (NM)
For a room like ours with 15-amp circuits, buy a 250-ft. coil of 14-2 W/G Type NM-B ($15 to $25). You’ll also need some three-conductor cable for the three-way switches.

Plastic Boxes
Plastic boxes are less expensive and easier to use than metal boxes. Buy single 18- or 20.3-cu.-in. nail-on boxes for receptacles and single switches, and double-, triple- or quadruple-switch boxes for multiple switches. Buy round boxes for light fixtures. Use round boxes with a bar hanger when the light fixture location is between studs or joists.

Wire Connectors (“Wire-Nuts”)
Buy a box each of red and yellow wire connectors. We recommend the type with wings. Buy green ground wire connectors if your inspector requires them. Read the instructions on the container to see how many wires each connector will hold and how much insulation to strip off the wire.

Odds and Ends
Buy a bag of fifty 1/2-in. staples. Pick up a half dozen metal nail plates to protect vulnerable cables and a roll of black electrical tape to mark white wires.

Special Boxes
Paddle Fan Box With Bar Hanger

Light Fixture Or Paddle Fan Box

For More Information

The following book offers helpful information on house wiring basics: Wiring a House by Rex Cauldwell, The Taunton Press, 1996. Available on-line at www.tauntonpress.com or call (800) 283-7252. $34.95 plus $3.95 shipping.