Dear Mr. Electrician: How do I fish wires in the wall? I don’t want to spend a lot of money for special tools that I may only use once. Can I use a metal coat hanger for wire pulling through a wall?
Answer: My experiences with using metal wire coat hangers to fish wires through walls and ceilings have not been very good. The metal used in the manufacture of coat hangers is a soft mild steel that bends easily. When a coat hanger wire is pushed into a wall it becomes distorted and is not very controllable as to direction. NOTE: Text links below go to applicable products on Amazon and EBay.
WIRE PULLING FISH TAPES
For working at home where you probably will not be installing long runs of electrical conduit, a twenty five foot fish tape would be adequate for your wire fishing jobs. In my inventory of tools I have several short pieces of fish tape of varying lengths from one foot to around eight feet. They were all broken off of much longer fish tapes after getting bent or twisted the wrong way
A metal Fish Tape is made of hardened steel with some flexibility built in. It is mostly rigid, but can be bent slightly to get around obstacles. It is excellent for fishing wires in walls and pulling wires through conduit. If the hook breaks, you can heat the metal up and bend a new one.
The sloped ceiling in the photo above made it easy for me to push my fish tape up into the attic. There was a space between the top plate of the wall and the ceiling joists big enough to put my hand through. Once the wire was pulled in it was simple to push it through a drilled hole in the top plate and then fish it down the wall to a new switch box.
When I began working on electrical jobs in the early 1960’s the metal fish tapes available at the time were either loose or on a rigid metal reel. The loose fish tapes were usually coiled into a short piece of flexible metal conduit.
I would cringe whenever I had to wind the fish tape back onto one of those old metal reels. My hands would hurt from trying to pull it into the tight metal grooves. Eventually an attachment winder was made to make the process easier. I was in wire pulling heaven after my father bought a new plastic reel to wind the fish tape on. So much easier.
WIRE PULLING FISH RODS
There are also Fiberglass Rods made for pulling wires through walls and ceilings. These are available in different lengths and thicknesses and are excellent for pushing through insulated walls. They don’t flex as much as a fish tape which is good if you are pushing it across an attic.
Wire pulling rods come in at least three different diameters depending on the manufacturer. 5/32″, 3/16″, 1/4′. The smallest diameter is extremely flexible and the largest diameter is slightly rigid. I tend to use the 3/16″ the most as it has a combination of flexibility and rigidity that is good for fishing up and down walls with insulation.
Fiberglass rods come with some accessory screw-in tips for different applications. At least one company makes additional accessories for attaching to rods. I have found them to be helpful in different situations. One accessory is a hook that is great for grapping wire across a suspended ceiling or an attic.
HOW I USE A WIRE COAT HANGER WHEN PULLING WIRE
I do keep a piece or two of coat hanger wire in my truck. One piece is about a foot long and bent into an L shape at each end. One bent end extends approximately 3.5″ and the other end extends approximately 2.5″.
Before I cut a hole in a wall or ceiling I will make a small hole (Approximately 1/4″) with an Awl or a long thin screwdriver into the center of the hole to be cut. First I insert a long thin screwdriver or a short piece of fish tape straight into the hole to probe for obstacles.
If I detect no obstructions I will insert the screwdriver or fish tape at a sharp angle in four different directions to feel for pipes, ducts, wood, wires or anything else that might inhibit the installation of something into the wall or ceiling.
My final step before cutting the hole is to insert the L shaped coat hanger into the wall or ceiling. I push the coat hanger in and out while rotating to sense for obstructions. I find that the coat hanger is particularly useful to detect anything that is up against the backside of the wallboard. It is the best way that I have found to determine if Resilient Channel has been used to reduce sound transmission.
Because the Resilient Channel is against the backside of the wallboard it is difficult to detect when inserting a straight probe such as a screwdriver. If there is insulation in the wall or ceiling you may find that it will inhibit the coat hanger and also cause it to bend as you push it in.
I have also found it helpful to use a metal wire coat hanger to hook onto things inside of a wall or ceiling. Sometimes I push my fish tape down a wall and it is just beyond my reach. A metal coat hanger with a hook on the end is pretty good at reaching inside of a wall to grab behind a wire or fish tape or even a fiberglass rod.
A metal wire coat hanger is a good tool to keep in your tool box along with other tools for pulling wires. It comes in handy sometimes.
I had to fish some wires when I added a dimmer and light fixture.