Cut off both ends of the extension cord with the wire cutter. Disassemble the 250-volt plug by removing the two screws that hold it together. Determine how much sheathing on the extension cord to remove and cut it off with the wire stripper. Only remove as much sheathing as necessary. The sheathing should fit into the plug's strain relief and end just before the wires attach to the terminals.
Strip 5/8 inches of insulation from the ends of all three wires and gently twist the strands on each wire. Loosen the three terminals with a screwdriver. Insert the stripped wire ends into the plug through the strain relief.
Wrap the green ground wire around the ground terminal clockwise. Tighten the ground terminal firmly. Ensure no loose strands of wire are free to move around inside the plug.
Wrap the remaining two wires clockwise around the two terminals. The order does not matter. Tighten the terminal screws firmly.
Reassemble the plug with the two screws. Tighten the strain relief to securely hold the cord in place, but not so tight that it crushes the cord. Repeat all these steps at the opposite end of the cord with the receptacle.
Things You Will Need
- Wire cutter
- Stranded wire stripper
- 250-volt cord plug
- 250-volt cord receptacle
- Modifying the cord is the best solution. You could also make two adapter cords following this same procedure. Make one adapter with a 110-volt plug on one end and a 250-volt receptacle on the other end, and another adapter with a 110-volt receptacle and a 250-volt plug. Plug the 110-volt extension cord into both adapters and it will work the same way.
- Only use medium- to heavy-duty cords with 14, 12 or 10 gauge wires that include a ground wire.