How to Fish a Wire Through a Wall

How to Fish a Wire Through a Wall

Fishing wire is much more frustrating than fishing for salmon or bass.

It’s fiddly work that requires numerous trips up and down from the attic or basement unless you have a helpful assistant.

I don’t blame you for calling in a pro to take care of the job. However, if you would like to save cash and learn a little, we’ve got you covered. 

In this guide, we’re going to teach you how to fish wire from the attic or basement into a wall.

Let’s go fish!

Why Would You Need to Fish Wire?

Before we start tearing into walls and clambering through the attic, let’s check that you actually need to do this. 

You generally need to fish wire through a wall to put a new electrical outlet or light switch in place. 

It’s important to remember that you can only fish wire through a stud wall. If you need to put a new outlet or switch into a concrete wall, you’ll have to chase a channel for the wire. 

Fishing allows you to drop or raise cables from the attic or basement through the wall to the new socket or outlet. You’ll need to know where your existing cables and circuits are before you start.

You don’t want to drill through the ceiling to find out that the wires are in the crawl space below the floor. 

That’s another thing to be aware of, the cables may be located in a crawl space above or below your room. It depends on the layout of your house and your wiring situation. 

Tools Required

You’ll need a few household tools and one or two specific items.

Remember to weigh up the cost of purchasing the tools against the cost of getting a pro in to do the wire. 

There’s not much point paying more for tools you might not use again if an electrician can do it cheaper. 

Here’s what you’ll need:

 

  • Eclectic drill. 
  • Fish tape. 
  • Stud finder. 
  • Voltage tester.
  • Drywall saw.
  • Level.
  • Stiff wire/ wire coat hanger. 
  • Torch.
  • Electrical tape.
  • ⅛ inch drill bit.
  • ½ inch drill bit. 
  • Spade drill bit.

In terms of materials, you’ll need:

  • NMB cable.
  • Light Switch or outlet.

Preparation

Before you even think about touching the drywall, you need to turn off the circuit breaker for the circuit you’re going to be working on. 

Once you’ve flipped the breaker switch, use a voltage tester on an outlet in that circuit. This will help you ensure that there is no electricity coming through the circuit. 

Another thing you’ll need to do before you begin is to check in with local building authorities. You’ll want to make sure that you are following all the necessary safety codes for your locality. 

How to Fish a Wire Through a Wall

Step 1: Mark and Cut the Outlet

The great thing about fishing wire through a wall is that you can choose where your new outlet or switch goes. 

Choose your spot and check for studs using a stud finder. You might also want to use a wire finder to make sure that there are no cables or pipes behind the wall already. 

If you’re trying to match other switches or outlets in the room, it’s a good idea to measure the distance from the floor so they’ll all be level. 

Once you’ve found your spot, hold the switch or outlet against the wall. Remember, that you want to hold the part that actually goes into the wall, not the front plate. 

Use a spirit level to make sure the outlet is straight. Then, trace around the outside of the switch or outlet using a pencil. 

With the outlet now sketched onto the wall, you can cut away the drywall. 

Use a drill with a ½ inch drill bit to make a hole near one section of the outline. You can then slip the drywall saw into the hole and cut along the lines you traced. 

There’s no need to worry about the outline being uneven or messy. It will be covered by the front plate later. 

Step 2: Make a Hole in the Ceiling or Floor 

Before you squeeze yourself into the crawlspace or attic, you’ll need to mark the correct spot. 

Your attic or crawl space is like another world. It’s difficult to tell or imagine what room you are above or below. It’s even more difficult to find the precise location of your wall. 

To help you find the right spot, take your ⅛ inch drill bit, and drill a hole in the ceiling or floor. Make sure the hole is directly above the hole you’ve cut for the outlet or switch. 

You want to make a hole that is big enough to push a stiff wire or a straightened coat hanger through. 

The hole should be as close to the wall as possible. If you’ve got coving along your ceiling and wall join, drill through the ceiling as close to the coving as possible. 

Once the hole is drilled, you need to feed stiff wire or a straightened coat hanger through the hole. You want a good 6 inches or so to make sure you’ll see it when you get into the attic or basement. 

The professional solution to this can be easily purchased from Amazon.

Gardner Bender EFT-15 Mini Cable Snake, 15 Ft Steel Fish Tape, Electrical Wire Fishing Tape, Red & Black

Step 3: Finding the Top or Bottom Plates

You can now head up to the attic or down to the basement to look for this bit of wire. 

When you spot it, you’re going to want to look for a 2×4 as close to the wire as possible. This 2×4 will be the top or bottom plate of the wall depending on whether you’re above the wall or below. 

Be aware if you’re up the attic. You’ll have longer wooden beams usually running the length or width of the attic. These are not the 2×4 you’re looking for. The 2×4 will be below these beams. 

When you’ve found the 2×4 you’ll need a spade drill bit to make a hole in the center of the 2×4. It needs to be large enough to take a cable with a bit of space. Remember that a larger hole will be easier to find with the fish tape.

Step 4: Go Fishing

This bit can get a bit frustrating. Try to be patient and work methodically. 

You’re going to use your fish tape for this step. Fish tape is a spool of spring steel. It’s fairly rigid allowing you to feed it up or down a wall without flopping. 

The tape will have a hook on the end that allows you to attach a wire to to bring it back down. 

You’ll need to feed the tape up or down to the hole you drilled in the top or bottom plates. It might be useful to have a helper waiting for the fish tape to poke through. 

If you’re having a bit of trouble getting the tape through the hole, use that rigid wire or coat hanger to pull the tape through. 

Step 5: Attach the Wire

Once you’ve got your fish tape through the hole in the plate, you need to attach the cable you want to run. 

Most fish tapes have a hook on the end that you can use to grab hold of a cable. However, to make sure you don’t lose the wire halfway through, use electrical tape to secure the wire. 

With the wire secure, you can now pull the fish tape back through the hole you made. Go slowly and carefully.

If you feel resistance or the cable seems stuck, push the fish tape back up and try again.

Step 6: Finish Your Installation

With the cable now run through the wall, you can finish installing your outlet or switch! 

Don’t forget to fill the hole you made in the ceiling or floor when you’re done!

Final Thoughts

There you have it, 6 steps to fish a cable through a wall.

It’s a fiddly but not overly complicated process.