The trouble with power cords is that they tend to get in the way, and if you're using an electric hedge trimmer, that can mean a severed cord. When you cut a cord, the first course of action is to turn off the power or unplug the half of the cord that's still plugged in. The next step isn't as obvious as you might think. The National Electric Code frowns on splicing the cord back together -- there's too great a chance of the connection separating or getting wet, even with shrink-wrap insulation. There's no problem, however, with replacing plugs.
Purchase a male plug for the end of the cord that is still attached to the trimmer. If the cord is long, cut it near the end, and you don't mind a slightly shorter cord, that's all you need. If you want to maintain the original length of the cord, however, purchase a female plug for the other end of the break. Make sure the plugs are rated for the wire gauge of the cord.
Install the male and female plugs using an identical procedure. Start by disassembling the plug to expose the terminals. Slide the part of the plug that covers the terminals along the cord.
Strip about 2 inches of plastic sheathing from the cord with a utility knife to expose the wires. You may have to work at this, especially if the wires are embedded in rubber. When cutting with the knife, always stroke away from you.
Separate the wires and strip away 1 inch of insulation with the knife or a wire stripper. If the wires are stranded, twist each one clockwise with pliers to tighten the strands.
Hook the wire coated with black insulation clockwise around the brass terminal in the plug and tighten the screw with a screwdriver. The screw also turns clockwise and should secure the wire onto the terminal as you tighten it. Connect the white wire to the silver terminal and the green or bare wire to the green grounding terminal in the same way.
Slide the cover down to meet the plug and push the two parts together. You usually need to secure them by tightening three screws in the plug face, but they may just snap together. Tighten the screw on the other end of the plug to clamp the wire and keep it from slipping out.
Plug the male and female plugs together to restore the cord to its original length or plug the male cord directly into a power outlet.