To replace the cord on a space heater, take out the cord-receptacle cover with pliers, remove the cord's wire connections, twist the wires of the new cord onto the attaching screws and attach the grounding wire. If a new plug is needed, repeat the wiring process on the plug attachment.
Begin by purchasing an appropriate replacement cord for the space heater, normally a 12- or 14-gauge insulated cord. If the new cord has no plug, find a compatible three-pronged plug to attach during installation of the new cord. Use a screwdriver or needle-nose pliers to remove the cord-receptacle cover to reach the cord connections. This may require removal of the heater's back panel. Note down the way in which the wires of the cord connect to the appliance, such as any special knotting or wire placement. Replicating the connections exactly creates a greater chance of success when replacing the cord. Remove these wire connections.
Use a utility knife to separate the wires of the new cord, being careful not to cut the protective coating or the fine wires within the two major wires. Take a wire stripper, and remove just enough coating from the wires to wrap the fine wires on the connector screws. Use needle-nose pliers to twist the fine wires into clusters, and wrap them around the left and right screws so that neither bundle touches the other. Attach the grounding wire to the screw in the middle, and repeat this wiring process for the plug, if necessary.