How to repair wire insulation

Sometimes wire insulation gets damaged. The wire will still work, but exposed metal increases the risk of short circuit, electrical shock, or even fire. When you come across damaged insulation, you really need to fix it. Here’s how to repair wire insulation.

Electrical tape

repair damaged wire insulation
The quick and dirty fix to repair damaged wire insulation is to just wrap it in electrical tape. This works, but it looks bad and eventually that tape is going to fall off and then you’re going to need to fix it again.

The easiest and cheapest option is to just wrap some vinyl electrical tape around the damaged insulation to shore it up. This works, but it doesn’t look professional. Then again, who’s ever going to look there? To me, the bigger downside besides appearance is that the adhesive will deteriorate over time. It will take years, but it’s not something I would consider a permanent repair.

Liquid electrical tape

Home improvement stores sell a polymer compound they call liquid electrical tape. Brush it onto the exposed wire, and it will bond with the surviving insulation and harden into a rubbery mass. It yields a more permanent repair, and if you’re careful, it looks more professional too. The downside is the cost, but a bottle of liquid electrical tape will do a large number of small repair jobs.

Heat shrink tubing

repair damaged wire insulation
In this photo, I repaired damaged wire insulation with heat shrink tubing rather than wrapping it with electrical tape. It’s a more permanent repair.

The most professional repair involves heat shrink tubing. As long as you can disconnect one end of the wire, you can simply slip a piece of tube over the wire, reconnect the other end, and then apply a heat to the tube with a heat gun or even a common hair dryer. The tube will shrink down and grip tightly onto whatever remains underneath. You can expect a package of assorted heat shrink tubing to cost around $4.

You may have to de-solder and re-solder some wire to use this method. Here’s some advice on soldering.

Replace the power plug

If the damage happens to be close to the plug and you don’t mind shortening the cable a bit, you can just cut off the wire near the plug, then replace the plug to solve the problem. All you need is a set of wire strippers/cutters, a screwdriver, and a replacement power plug, which won’t cost you much more than a couple of dollars.

Cut off the wire as close to the damage as you can with a pair of wire cutters. Strip off about a half-inch of insulation from both wires, then twist the copper strands together nice and tight.

Disassemble the replacement plug, then thread the two wires through the hole in the plug. There are two screws inside. Bend each wire into a U shape, and loop one wire over one of the screws and the other wire over the other. Cinch the U shape closed, then tighten the screws. Slide the protective plate over the end of the plug. And that’s it.

Outright replacement

If the insulation is too far gone, it might be cheaper and/or easier to just replace the wire altogether with new wire. This may involve soldering, but read my piece on soldering I linked to above. It’s not as hard as it sounds.

2 thoughts on “How to repair wire insulation

  • October 28, 2016 at 10:29 am
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    Dave,

    I have the opposite problem: how to remove the insulation from the tiny wires in a headphone cord so I can resolder a new jack.

    A match doesn’t work. 0000 steel wool doesn’t work. Acetone doesn’t work. Am going to try brake cleaner, then Jasco (Methylene Chloride) assuming I can find some.

    • October 28, 2016 at 3:27 pm
      Permalink

      That sounds like it would make a good blog entry. Normally what I do on very thin wire is burn the insulation off with a junk soldering tip. Avoid using your good one.

      I’ve also heard of people whittling the insulation off with a very sharp knife or razor blade until they expose the wire on one side, then folding the insulation back and cutting it off. Sandpaper might also work. I’d use something coarser than 0000 steel wool. I’d go with more like 60 grit sandpaper or #1 steel wool and abrade in one direction. 0000 steel wool is so fine it will polish the insulation rather than wear through it.

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