How to Install Surface Wiring

A cable with exposed wires
  • 8 hours
  • Advanced
  • 550
What You'll Need
Needle-nose Pliers
Drill Bits
Measuring Tape
Voltage tester
Spirit Level
Wire Stripper
Rubber Mallet
Opened-back wire-mold box
Closed-back wire-mold box
10’ lengths of wire-mold
Internal 90-degree elbow bend
Black, White and Green THHN wire
Wire-mold clips

Household electrical work can be an intimidating thing for many homeowners. The thought of cutting holes in drywall, drilling holes in studs and fishing wires through the walls can send even the sturdiest do-it-yourselfer scurrying to the phone to call a costly electrician.

There’s no need to do that. Sure, in some areas of the house, you will want as much concealed as possible, but there are places where the eyes of guests don’t wander too often. In those areas, you can save a ton of money and install surface wiring.

What is surface wiring? Surface wiring is a metal “raceway”, or “wire-mold” that easily allows you to add an outlet, a switch or a light fixture in an area where there is none. All of the components are mounted to the surface of the wall so you don’t have to cut holes and fish wires through walls. The uses for surface wiring are limited by your imagination. You can add a hard-wired carbon monoxide detector to the smoke detector, you can add a switch to control an outlet or you can add a light fixture to the other side of the ceiling, really, the uses are endless.

Surface wiring is a means by which the electrical wires travel from outlet to outlet. The raceways come in two different styles. The traditional metal raceway is used for electrical purposes and the plastic raceway is used for low-voltage applications or for computer network systems.

For the metal raceway surface mounting system, there are a few parts needed for a successful installation. First, there are clips that get screwed into the wall. The clips hold onto the metal raceway, keeping it secure to the wall. Next, there are internal and external elbows, as well as 90-degree turns. They allow you to maneuver the raceway over and around soffits, corner bends and up or down-turns. Also needed, will be an opened or closed-back junction box, or round “pancake” box for light fixtures.

A plastic raceway is very easy to install because it is usually connected to the wall with double-sided tape since it never carries higher voltage wires.

Installation of metal raceway surface wiring is pretty easy. It is important to make everything level because it is easily detected when it’s installed crooked. The first thing to do is to plan out the entire installation before proceeding.

For this example, we’re going to add an additional outlet on a neighboring side wall where there is currently no outlet. For this job you will need:

• Screwdrivers
• Hacksaw
• Needle-nose Pliers
• Drill and drill-bits
• Plastic anchor set with flat-head screws
• Pencil
• Electrical Tape
• Voltage Tester
• Rubber Mallet
• Wire Strippers
• Level • (1) opened-back wire-mold box
• (1) closed-back wire-mold box
• (2) 10’ lengths of wire-mold
• (1) internal 90-degree elbow bend
• Wire-mold clips
• Measuring Tape
• 30’ of black, white and green THHN wire

The first thing to do on all electrical jobs is to turn OFF the power to the circuit you’re working on. Once that is done, remove the cover plate and unscrew the outlet from the box. Take the opened-back junction box and screw the backplate to the wall box. On the top, sides, and bottoms, you’ll see tabs on the backplate. We will use the one on the right, in the center. Measure from the point where the tab gets split on the backplate. So you’re adding the entire tab as part of the measurement, to the corner of the wall. Write down that number. Now, measure the portion of the internal elbow from the corner to the start of its tab. Subtract that number from the first measurement. That’s how long your wire-mold length will need to be.

Measure and mark the wire-mold and cut it with the hacksaw. Use the needle-nose pliers to smooth out any rough edges on the inside of the wire mold's cut end. Slide the back part of the corner bend into one end of the wire-mold. Slide the other end of the wire mold over the tab on the junction box. Lay the wire-mold against the wall and make it level. Mark the wall every 12 inches above and below the wire-mold. Also, mark the holes where the corner bend will get screwed to the wall.

Remove the wire-mold from the junction box and grab the clips. In the center of the clips, you will see a hole. Position the clip between the lines you traced on the wall and color in the hole with a pencil. Use the drill bit to drill a hole for the anchor. Keep the hole slightly smaller than the anchor. Slide the anchor in the hole and tap it until it’s fully inserted. Screw the clip into the anchor. Do that with every clip and the holes where the corner bend is located, but do not screw the corner bend in place yet.

Now, slide the wire-mold over the junction box tab again and place the lower end of the wire-mold into the bottom groove of the clip. Use the rubber mallet to lightly hit the top of the wire-mold so it snaps into the clip. In the corner, your corner bend should line up with the anchors you installed. Screw it into place and then check again to make sure everything is level so far.

On the wall where we are installing the new outlet, determine where you want it and cut a length of wire-mold to that length. Connect the backplate of the closed-back junction box to the wire-mold and level it against the wall the same way as you did the first length. Connect it to the wall with clips the same way you did the other length. Lastly, mark the holes on the backplate and use anchors to attach it to the wall.

Take the three wires and tape them together at one end. Starting at the original outlet, slide the wires through the wire-mold until it reaches the corner. Then, slide them down the next length of wire-mold until they come out the end. Leave about 12 inches at each end and cut away the rest. Connect the corner bend’s cover plate (it just snaps into place). Connect the wires to the outlet at the new junction box and screw the box to the backplate. The outlet gets screwed to the box and then screw on the cover.

Make the necessary connections at the original outlet and screw on the box and plate the same as you did with the other box. Turn the power back on and test for proper voltage at both outlets.

Wire-mold is neat, convenient and can even be painted. In many applications, it can even be installed in a nearly invisible way, such as around door frames or above the baseboard. It’s an inexpensive and easy solution to getting more electrical access without calling in the expensive troops.