How to Use Electrical Wire Connectors

Electrical wires.
  • 1-3 hours
  • Intermediate
  • 0-50
What You'll Need
Wire stripper
Wire cutter
Electrical wire connector
What You'll Need
Wire stripper
Wire cutter
Electrical wire connector

Electrical wire connectors are a common and easy way to splice two current-carrying electrical wires together. Unlike many electrical wiring projects, installing an electrical wire connector is easy enough for a non-professional to do and requires very few tools. It is important to note, though, that there are many different types of wire connectors. Some crimp-on, while others simply slide on, and twist-on. The steps below will explain how to use the most common type: the twist-on wire connector.

Step 1 - Turn Off the Power

Pick up electrical connectors on Amazon.

To avoid dangerous electrical shocks always turn off the power before working on any wiring project.

Step 2 - Choose the Right Size Wire Connector

Almost as important as turning off the power, choosing the right size wire to connect for the job can prevent mechanical and electrical failure and prevent electrical fires. The reason for this is that when a switch or device is turned on, it causes an electrical current to flow through to wires and into the wire connector. Once the current reaches the connector, it encounters a mild resistance in its flow. The resistance causes the wires themselves to heat up slightly which, in turn, causes them to expand.

Once the switch is turned off again and the current has been stopped, the wires will cool and contract once again to their normal size. If the wrong size wire connector has been applied, it may pop off when the wire expands or simply fall off when the wire contracts. Either way, the conductors of the wires will be left exposed, which can potentially cause all kinds of problems. To choose the right size wire connector, look on the side of the connector box and make sure that the connector being used is rated for the size of the wire it is being connected to and also for the number of conductors that are in the wire.

Step 3 - Strip the Wires that are Being Connected

Using a wire stripper, remove the coating around the ends of the two wires that need to be connected. No more than 3/8 inch of the coating needs to be removed.

Step 4 - Place the Two Stripped Ends Together

Line up the two wires so that they are parallel with each other. Some electricians will twist the wires together before placing the connector on them. There is no harm in doing this; however, in order to be UL-listed (which means it was approved by a safety testing board) a connector must make a firm connection without twisting the wires, so applying the connector without twisting the wires will also work. In fact, twisting the wires together before installing the connector may make future repairs on that splice more difficult as the two wires will be more difficult to separate.

Step 5 - Place the Connector Over the Ends of the Wires

Whether the wires are twisted or simply lined up parallel with each other, place the cap portion of the wire connector over the exposed conductors of the two wires. Check to make sure that none of the exposed conductor material is protruding from the bottom of the connector. If some of the exposed wire does protrude, remove the cap and clip off a little of the end with a wire cutter and try again.

Step 6 - Twist the Connector On

Once the connector covers the entirety of the exposed wires, twist the connector clockwise until it feels very tight. Finally, test the quality and strength of the splice by holding the connector and trying to firmly pull each wire free. Remember, if the wire connector isn’t as tight as possible, the cap may have slipped off.

When you purchase through links on our site, we may earn commissions at no cost to you.