The Problem: Scorched, charred or burned wire in an electrical box
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. The
usual reason insulation gets
ruined is that the bulbs in the
fixture exceeded the fixture’s
wattage rating. That extra heat
literally baked the insulation.
Usually the insulation outside of
the ceiling box is OK. 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’s
not an acceptable long-term fix.
Here’s the right way to fix the
How to fix burned wires
1 of 3
Photo 1: Get new wire insulation
Peel off the outer jacket of 12-2
nonmetallic cable. Then strip off about 8 in. of
insulation from the black and white wires.
2 of 3
Photo 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
3 of 3
Photo 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
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.
Strip insulation off the 12-gauge
wires (Photo 1). Next, slide the
new insulation onto the old
wires (Photo 2). Then secure
the new insulation with heat
shrinkable tubing (Photo 3).
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