Dear Mr. Electrician: 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 fishing wires 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.
A metal Fish Tape is made of hardened steel making it rigid and not very bendable. There are also Fiberglass Rods made for fishing wires through walls and ceilings. These are available in different lengths and thicknesses and are excellent for pushing through insulated walls.
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 (Around 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 straight into the hole to probe for obstacles. If I detect no obstructions I will insert the long thin screwdriver 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.
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 fishing wires. It comes in handy sometimes.
Click here to read my post about installing an electrical box in an existing wall.