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.
Electrical wire insulation repair.
Electrical wire insulation for lamp and appliance cords is made from flexible polyvinyl chloride and electrical house wiring insulation consists of a thermoplastic high heat nylon material.
Materials and labor for repairs.
The easiest and cheapest option is to just wrap some vinyl electrical tape around the damaged insulation to shore it up.
Look at the electrical wire where the insulation is damaged.
The insulation covers the wire and it can be damaged through everyday use.
Inline barrel crimp type splice connectors work well where the wires may be cut short.
Use a wide crimping tool which will provide a good crimp of the spliced wire.
Wrap heat shrink sleeve around the cable and install the steel closure channel over the raised profiles of the heat shrink sleeve and centre the repair sleeve over the cable damage section.
Pick up a short length of 12 2 nonmetallic cable and a package of heat shrinkable tubing.
Use electrical tape to cover up the nicks made to the wire insulation.
Then strip off about 8 in.
Inline splice repair for wires that are cut short.
Use yellow flame tip of a suitable heat shrink propane torch start heating the metal channel area first for about half a minute.
Use a blow dryer or a heat shrink gun to shrink the tubing onto the wire.
Peel off the outer jacket of 12 2 nonmetallic cable.
Slide heat shrink tubing over the damaged insulation area if the wire is not part of an electrical extension cord or power cord.
As long as the copper conductors inside the wires are not damaged however the insulation is repairable.
Since the wiring in a ceiling fixture is usually 14 gauge you can fix it with insulation stripped from a 12 gauge wire.
If the wire is nicked or cut repair the wire before repairing the insulation.