How To Fix Burnt Wire

Updated: Jan. 29, 2024

How to fix the insulation on burned wire quickly and easily

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Fix burned wire inside electrical boxes by replacing charred insulation. You can do this quickly and easily without pulling in new wires.

Tools Required

  • Wire stripper/cutter

Materials Required

  • 12 gauge electrical wire
  • Heat shrinkable tubing

Assessing the problem

So you’re finally getting around to replacing the ceiling light fixture when you discover that the wiring insulation has turned to charcoal and cracked off. Insulation typically gets ruined when the bulbs in the fixture exceed the fixture’s wattage rating. That extra heat literally bakes the insulation. Usually, the insulation outside of the ceiling box will be okay. But you’ll have to repair the damaged insulation inside the box. No, you can’t just wrap the bare wires with electrical tape. That might make you feel better, but it’s not an acceptable long-term solution. Here’s the right way to fix the problem.

Project step-by-step (3)

Step 1

Get new wire insulation

Since the wiring in a ceiling fixture is usually 14-gauge, you can fix it with insulation stripped from a 12-gauge wire. Pick up a short length of 12-2 nonmetallic cable and a package of heat shrinkable tubing. Peel off the outer jacket of 12-2 nonmetallic cable. Then strip off about 8 in. of insulation from the black and white wires.

A person holding a pair of yellow wire cutters.TMB Studio

Step 2

Reinsulate the old wires

Remove as much old insulation as possible. Then straighten out the old bare wire. Slide on new insulation (white goes on the neutral, black on the “hot”). Hold the insulation in place and slide on a short piece of heat-shrinkable tubing.

A person is putting insulation on a ceiling.TMB Studio

Step 3

Shrink the tubing

Wave the flame from a lighter under the heat-shrinkable tubing. Keep the flame moving so the heat does all the work and the tubing doesn’t burn. When you’re done, you can connect the new fixture without worrying about the old wires shorting out. Just be sure to follow the wattage maximum of the fixture when you select bulbs.

Waving the flame from a lighter on sealingTMB Studio