Fishing Electrical Wire Through Walls

Run electrical cable through walls and across ceilings without tearing them apart

Add wiring for new switches, fixtures and outlets anywhere in the house, with minimal wall damage. Learn how to use fish tapes, flex bits and glow rods to pull wire through walls and across ceilings, quickly and efficiently.

By the DIY experts of The Family Handyman Magazine

TIME

One day

COMPLEXITY

Simple

COST

$20 - $100

Running wire with a fish tape

Running wire from a switch location to a light or fan in the center of the ceiling can be a challenging project. You'll almost always have to cut some holes in the walls, but you can minimize ceiling damage by using a “fish tape.” A fish tape is a long strip of spring steel used for pulling wires through walls and ceilings. They're available at hardware stores and home centers.

To map out the best path for the cable run from the switch to the light, first determine the ceiling joist direction. Generally, it's best to run the cable in the space between the joists so you won't have to cut a lot of holes in the ceiling. Then figure how to get the cable through the wall to that joist space.

Since you can't run the cable through the attic, the next best choice is to go down into a basement or crawl space, then go back up through the stud cavity directly below the joist space. If you can't go down, follow the procedure we show here, which is to go horizontally across the studs until you're below the joist space. As you can see in Photo 2, you'll have to notch each stud and the top plate.

Once you know the path of the cable, cut a hole in the ceiling for the chandelier outlet. At each location where the cable will cross a framing member, cut away the drywall. Where the cable will turn from the wall to enter the ceiling, cut out a 3-in.-wide section of drywall in the wall and ceiling (Photo 1). Extend the openings at least 2 in. from the edge of the top plate.

With a sharp 5/8-in. or 3/4-in. chisel, trim the stud or plate back about 1/8 in. so that the guard plate will sit flush with the face of the framing (Photo 4). Then chisel the notches for the cable (Photo 2).

Feed the fish tape from the opening at the top plate to the lighting outlet, connect the cable and pull it through (Photo 3). Then feed the fish tape from your wall switch to the top plate opening, connect the cable and pull it through the wall.

Be sure to install nail guards that completely cover the cable where it crosses the framing (Photo 4). Wire the switch and the lighting outlet, then patch the holes in the wall and repaint.

The Tools You Need

Flex bits, glow rods and fish tapes are the tools electricians use to fish wires and communication wire. Flex bits are great for drilling holes in hard-to- reach spaces (see “Invest in a Bumper Ball,” below). The two most common lengths are 5 ft. and 6 ft., but extensions are also available. A 3/4-in. x 54-in. flex bit costs about $50 at home centers. Buy a bit that has a hole on the end of it so you can use the bit itself to pull wires.

Once your hole is drilled, you can shove a fish tape or glow rod through the hole, attach your wire to the eyelet at the end and pull it back through. Glow rods can also be used to hook wires to pull them out. As their name suggests, glow rods glow in the dark. This makes them easier to spot when you’re working in dark areas (which is most of the time).

Glow rods come in various lengths and thicknesses, and you can combine as many sections as the job requires. Thinner rods flex more and work better when you have to make sharp turns. A thicker rod can span longer distances and is better for hooking wires that are more than a few feet away. A 9-ft. glow rod kit costs about $40 to $50 at home centers. You can also buy a 24-ft. kit.

Fish tape
Flex bit and glow rods
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Push through more than you need

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Hook on to a flex bit

Seal the Holes

If you’re drilling holes through top and bottom plates or running wires through a fire wall in the garage, you must seal those holes with a fire-resistant caulk or foam sealant to comply with fire and energy codes. Most building officials won’t make you bust out large holes in ceilings and walls in order to access hard-to-reach holes, but check with your local official before you begin your project. A can of fire-blocking insulated foam sealant costs about $10 at home centers and hardware stores.

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Fish wires through the holes for recessed lights

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Protect drywall with a mud ring

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Install conduit inside cabinets

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Invest in a bumper ball

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Hold on tight

Don’t Spin Apart the Glow Rods

Sometimes you need to twist and spin glow rods in order to snake them past ductwork, pipes and other obstructions. A great way to lose a rod or attachment in a wall or joist space is to twist it so many times in the same direction that it unthreads and comes apart. Some pros wrap a little electrical tape around the connections to keep them secure.

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Get a better view with an inspection mirror

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Don’t spin the bit in insulation

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Keep low-voltage wires away from electrical cables

Buy Extra Wire

Have plenty of extra wire or cable on hand, because i’s not likely that you’ll be able to fish a wire in a straight line from Point A to Point B. There’s also the possibility that your wire might get hung up on something, and you'd have to abandon it and start over.

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Required Tools for this Project

Have the necessary tools for this DIY project lined up before you start—you’ll save time and frustration.

  • Cordless drill
  • Stud finder
  • Bumper balls
  • Glow rod
  • Electrical tape
  • Drywall saw
  • Reciprocating saw
  • Flex bit
  • Inspection mirror
  • Wood chisel

Fish tape

Required Materials for this Project

Avoid last-minute shopping trips by having all your materials ready ahead of time. Here's a list.

  • Electrical cable
  • Nail guard (wire protector)
  • Mud ring
  • Low-voltage wire
  • Metal conduit