How to Replace Extension Cord Plugs

Repairing Extension Cords

A series of extension cords
Sam Bloomberg-Rissman/Getty Images

Extension cords can be damaged in many different ways, from dragging along the ground to getting run over by vehicles or closed into doors. Perhaps the most common damage comes from pulling out the cord by the cord—not the plug. Eventually, this stretches out the cord wires and separates the sheathing, or outer jacket, from the plug, exposing the cord wires. One more result of wear and tear is the ground prong (from a 3-prong, or grounded, cord) coming loose. When this happens, it's time to replace the plug.

Replacing a plug is an easy job that takes only a few minutes. It's also the only repair you should make to an extension cord. Cords with damaged sheathing, exposed wires, or other damage to the cord itself should be replaced. Just wrapping the cord with electrical tape isn't good enough. You don't know how much damage the cord has suffered, and electrical tape provides unreliable protection against shock. 

Supplies Needed:

  • Wire-cutting pliers
  • Replacement plug
  • Utility knife
  • Wire strippers
  • Phillips screwdriver

Cut Off the Old Plug and Fit the New

Cutting off the bad cord plug
Timothy Thiele

Make sure the cord is unplugged from any power source. Cut off the old plug from the cord, using wire-cutting pliers. Cut off any damaged portion at the end of the cord. Slide the new plug over the cut end of the cord and out of the way for now. Some plugs have two parts, with one piece containing the wiring connections and prongs and another piece that is an outer shell or body. In this case, slide the only the shell onto the cord for now.

Warning: The replacement plug must have the same amperage and voltage ratings as the cord. These ratings are printed on the plug. The ratings on the old plug will indicate the type you need.

Strip the Outer Jacket

Cut partially through the outer jacket of the cord, using a utility knife. You must be careful not to cut all the way through the jacket because you may also cut through the insulation on the cord wires, creating a serious shock or fire hazard. The cut should extend 3 inches from the end of the cord. Split the jacket with your fingernails (at the end of the cord) and peel the two sides apart along the cut. Trim off the loose jacket with the cutting pliers.

Strip the Wire Insulation

Strip 3/4 inch of insulation from the end of each cord wire, using wire strippers. Use the notch on the strippers that precisely matches the diameter of the wire.

Tie an Underwriter's Knot

Stripped wires in an electrical cord
Timothy Thiele

Tie the white (neutral) and black (hot) cord wires into an underwriter's knot, if there is room for the knot inside the cord body. This provides added protection against the cord wires separating from the plug connections if the cord is tugged. If there isn't enough room for an underwriter's knot, it's okay not to make one as long as the plug has a clamping device for securing the cord.

Connect the Cord Wires

Cord plug connections
Timothy Thiele

Loosen the terminal screws on the plug, using a screwdriver. Wrap the bare end of the black (hot) wire clockwise around the brass terminal. Tighten the screw onto the wire. Make sure that there are no stray wire hairs sticking out from the connection. Wrapping the wire clockwise ensures that the wire loop tightens around the screw as the screw is tightened.

Connect the white (neutral) wire to the silver terminal, and connect the green (ground) wire to the ground screw, using the same technique. The ground screw may be marked with green coloring, but in any case, it is connected to the U-shaped ground prong on the plug. Double-check the connections for tightness by pulling gently on each wire.

Secure the Plug

Hands attaching a plug cover
Timothy Thiele

Tighten the plug clamp onto the cord, using the screwdriver. If the plug is in two parts, slide the body up to the wiring half of the plug and join the two parts with the provided screws, then tighten the cord clamp on the body.