How can magnets be used to install wires inside an existing wall? Magnets can help run wires in tough locations, even if there’s insulation in the wall. We grab a few magnets and demonstrate the wire-fishing trick.
When adding wiring to an existing home or office, it can be a challenge getting cables behind a wall. Wires don’t like to be pushed! This is especially true of relatively thin wires, like network or audio cables.
Typically, a string or chain is put into position first, which is then used to pull the electrical wires through. The question is, how do you get that string there in the first place?
We took a sturdy chain and attached a powerful, ¾” diameter RC4CDIA ring magnet to the end. While other magnets can work, this diametrically magnetized ring magnet is great. It is strong and tends to easily rotate around to orient itself properly. We've heard from a number of customers who use this exact magnet for running pull strings.
The idea is to drop this magnet behind the wall, and use a second magnet to fish it through to where the cable needs to go. Whether sticking the magnet into the wall from above in the attic, or from below in the basement, the idea is the same.
To move the magnet around through the wall, we need a strong magnet on the outside. For this demonstration, we chose a plastic coated, 1" square BX0X08DCSPC-BLK block magnet. It’s very strong and has a countersunk hole. We stuck a screw through the hole to mount it to a cabinet knob, which makes holding and handling the strong magnet a bit easier.
It’s also plastic coated, which protects it from damage due to impacts and prevents scratches on the painted drywall.
The big block magnet outside the wall can move the ring magnet around quite well, even through thick drywall. To show a “cutaway” view of the idea, see how they attract through a thick textbook. Magnets as strong as these work well through ½” or 5/8” drywall.
In the videos below, we show a demonstration of these magnets in action. The first shows assembly of the parts, and the second shows how to pull wires through.
We’ve heard from a number of customers who have used these magnets to fish wires through walls. It seemed like such a great idea, we had to share it with everyone. The RC4CDIA ring magnet is a popular choice for the magnet used inside the wall.
There are many options you could consider for the magnet outside the wall. The BX0X08DCSPC-BLK block seemed strong enough to us. It's our first choice.
Some folks have used even larger magnets. Some have used a disc as large as the 1.5” diameter DX8C! While this is a stronger choice, it is definitely a powerful magnet that must be handled with extreme care. Please be careful when handling such large, powerful magnets.
Good luck with your next wiring project!