It happens: you're weed-eating your lawn and you slice straight through your electrical cord. Electrical cords are not inexpensive, and having to replace one may not be feasible for your wallet. Electrical cords can be repaired safely when damaged. Although electrical tape always seems to be the quick fix for any electrical problem, additional precautions need to be taken when splicing electrical cords.
Trim the ends of the cut electrical cord. Use wire cutter/strippers to cut the exterior insulation away from the interior wire conductors. Remove 25 mm (1 inch) of insulation off each end of the cut electrical cord.
Strip and trim the interior wires. Trim the white, black and green interior wire conductors to clean away any rough cuts on the wires. Strip 12 mm (1/2 inch) of insulation off each interior wire conductor to expose bare copper wiring.
Slide heat-shrinkable electrical tubing over one end of the electrical cord. Choose an outside diameter size of tubing that fits over your electrical cord and slide it up and away from the cuts. The tubing needs to be in place prior to repairing the wiring.
Splice the interior wire connectors. Slide heat-shrinkable electrical tubing over each interior conductor wire, moving it up and away from your splice location. The tubing must be in place before splicing the wires. Lay the black interior conductor wires from each side of the cut, parallel to each other so that the exposed bare copper wiring is touching. Twist the bare copper wiring together using your fingers, then slide the heat-shrinkable electrical tubing over the twist. Repeat this process for the white wires and the green wires. Use a blow-dryer and follow the manufacturer's directions on shrinking the tubing.
Slide the exterior heat-shrinkable electrical tubing that you placed onto the cord in Step 3 over the spliced wires, and shrink the tubing according to the manufacturer's directions. Wrap the heat shrink tubing and the electrical cord with electrical tape for additional protection.