wikiHow to Repair a Drill Power Cord

Drills and other power tools can make a job go easier and more quickly, but damaged tools can be dangerous to use. Repairing a power cord on a basic electric drill can extend the life of the tool and make it much safer to use.


  1. Image titled Repair a Drill Power Cord Step 1
    Determine the damage to your tool. The tool in the illustrations has damage caused by misuse or poor tool maintenance, but the problem isn't always this obvious. You can take the following steps to try to determine where the problem is with your drill:
    • Make sure the drill is plugged into a receptacle that has the correct voltage. You might plug a similar tool into the same receptacle to test the power, and if the alternate tool works, you can continue.
    • Inspect the tool and its power cord. Most drills are double insulated, so if you see burnt connectors on the plug, or one is missing, you can assume that this might be causing the problem. Look for damaged insulation or other signs of a problem as well.
    • Smell the drill's motor where the vents are visible. If the internal parts have overheated, there will be a distinct odor of burnt plastic.
    • Hold the trigger in the "on" position and tap the drill lightly, making sure the chuck is in a safe position. Loose wires and bad brushes sometimes will allow the drill to run intermittently when you tap the drill.
  2. Image titled Repair a Drill Power Cord Step 2
    Make sure that the drill is disconnected from any power source. Remove the drill's switch cover so you can test the wires and motor after you have completed the previous steps. If you have already determined the cord is damaged, you can probably skip the testing steps and proceed with repairs.
    • Test the drill's power cord for continuity with an ohmmeter to determine if the conductors are broken. This can be done by connecting the test leads to the prong on each side and the terminal at the drill's switch.
    • If you read continuity on each wire, you can test the switch itself. Squeeze the trigger while contacting the terminals on each side to see if the circuit through the switch is making a connection.
  3. Image titled Repair a Drill Power Cord Step 3
    Remove the terminal wires from the switch after you have determined the problem with the tool is in the power cord. Many drills (and other tools) have screw type connections at the switch; these are removed by simply loosening the screws and removing the wires. For stabbed in connections, you might insert a small diameter sharp instrument next to the wire to depress the locking tag that secures the wire, then pull the wire free from the connector.
  4. Image titled Repair a Drill Power Cord Step 4
    Remove the clamp that secures the power cord to the drill motor housing (this is a stress relief clamp that protects the internal connection).
  5. Image titled Repair a Drill Power Cord Step 5
    Pull the cord out of the drill housing, and remove the factor boot, or cord protector from it. If the power cord has obvious damage near the drill, you may be able to cut the damaged section from the cord and reuse it, although it will be substantially shorter than when it was new.
  6. Image titled Repair a Drill Power Cord Step 6
    Find a replacement power cord for the drill. If your drill is double insulated, you need to replace the cord with a two-wire cord the same size as the original; if it is grounded, use a three-wire, three pronged cord for a replacement. Do not use a two wire cord for a grounded tool.
  7. Image titled Repair a Drill Power Cord Step 7
    Strip the insulation jacket off of about 3 to 5 inches (7.5-12.5cm) of the replacement cord, then strip the conductor insulation back about 3/4 inch (2cm), being careful not to nick or damage the wire strands.
  8. 8
    Slide the cord boot onto the new cord, letting it slip down several inches from the stripped insulation jacket.
  9. 9
    Insert the wires into the holes (or clamp them onto the terminals) where the old ones were removed, making sure the same colored wires go on the same terminals. Tighten the clamps/screws tightly if applicable.
  10. Image titled Repair a Drill Power Cord Step 10
    Re-install the cord clamp and tighten it securely, then slip the cord boot into its slot. Replace the drill switch cover, tightening all of its fasteners snugly.
  11. Image titled Repair a Drill Power Cord Step 11
    Test the drill to make sure it runs. If it fails to operate, you may find you need to replace the switch or the brushes, but otherwise, you will need to replace the drill.


  • Save cords, switches, and chucks from hopelessly damaged drills or other tools if they are still serviceable.
  • Clean the internal parts of the drill and re-grease the gears and bearings if needed while the drill is disassembled.
  • Tin the wires with rosin core solder to make a better connection if desired.


  • Never hold or lift a power tool by its power cord.
  • Make sure the tool is unplugged before servicing internal electrical parts.
  • Keep power tools clean and dry.
  • Use the same size and type cord when replacing a power tool cord.

Things You'll Need

  • Screwdriver
  • Replacement cord (if needed)
  • Ohmmeter or Multimeter
  • Sharp knife or stripping pliers

Article Info

Featured Article

Categories: Featured Articles | Cabling and Wiring Connection