If you have an electrical cord that needs repair, do not despair. Electrical cables supply power to just about every home appliance, tool, and outlet. Damage to the cable/cord can cause electrical shorts that prevent current from transmitting. Repairing an electrical cable involves a few basic steps.
Step 1 - Perform a Visual Inspection
Sometimes a simple inspection of the cable or cord will reveal the problem. If it has been cut or broken, this could cause an electrical short. Any exposed wires pose a serious problem.
Step 2 - Test for Continuity
Begin by testing to see if the cable transmits electricity. This is also known as testing the cable's continuity. There are a few ways to test the continuity depending on what type of cable you have.
If you are testing a 120 or 240-volt cable, disconnect the power by unplugging it. Now remove the cable from the unit (appliance, tool, etc.) or short-out the wires at the appliance's end of the cord by clipping a jumper wire across them. Using your multimeter, attach the probes to each of the cord's prongs. Since there should be no resistance or electrical flow, the meter should read zero ohms. Now move the cord by flexing or bending it. If the meter reading changes, the cord is faulty and needs replacing.
If you are testing a removable cable or cord, follow the same instructions as above, except clip a jumper cable across the male plug and insert the multimeter probes into the female plug. After bending the cord, the meter should still read zero ohms. If it does not, replace it.
Step 3 - Replace the Cable
If the cable or cord has exposed wire but the continuity test reads okay, you may be able to use electrical tape to patch the cord. It is possible that the cord is shorting because the exposed wire is coming into contact with another object. If the continuity tests came back negative regarding the cord's function, it's time to replace it.
To replace the cord, you will need an identical new one. Connect the new cord the same way you disconnected the old one. Cut back the insulation to expose the cord wires and attach them to the same device terminals. If you are replacing a section of electrical wire, use the wire strippers to cut insulation from the new wire. Cut back enough insulation for it to wire or splice with the end(s) of the existing wire. Use wire nuts to connect the ends together. If you are replacing a power cord and it did not come with a plug, they can be purchased separately. Install the plug using the manufacturer's instructions.