A Guide to Wire Connectors

Wire connectors, or wire nuts as they're often referred to, are covers that are used to fasten two electrical wires together. These handy little connectors prevent live wires from becoming exposed or touching metal surfaces, which could cause a dangerous fault or short circuit.

Wire connectors are available in a variety of colors, materials, shapes, and sizes. Some of the most popular wire connectors are the twist-on, push-on, and crimp-on styles. Unlike a lot of electrical wiring projects, working with and using electrical wire connectors is easy for DIY amateur electricians and requires very few tools. As with any electrical project and when using wire connectors, be sure the electricity is shut off to the circuit you'll be working with.

In addition to making sure the electricity is turned off, it's important to select the correct size wire connector for your job. After the connectors are put in place and the electricity is switched back on, the current will obviously reflow through the wires, as well as the connectors, where it will meet with a mild resistance in its flow. This resistance will cause the wires to slightly heat up, causing them to expand. Conversely, when the current flow is stopped, the wires will cool and contract. If the wrong size connector is used, it could pop off when the wires heat and expand or fall off when they cool and contract. This will leave you with exposed wiring, which could lead to big problems. To avoid this issue, be sure the connector being used is rated for the wires it's connecting.

These are available with external grooves or with wings for easy handling and are typically twisted on by hand. To use, strip the two wires to be connected about ½" from the end. Align side-by-side and twist together the stripped area of the wires, slide the connecter over the two wires, and twist it clockwise to make the connection. They are held in place by interior grooves or a tapered coiled metal spring inside the connector, which threads onto the joined wires to hold them tightly together. If you need to remove the connector, simply twist it counter-clockwise until it comes loose.

Twist-on connectors are commonly color-coded to indicate the size or capacity of the connector. Easy to twist on and off if necessary, they're often used in electrical wiring systems for light switches, ceiling fans, electrical receptacles or outlets, security systems, HVAC, and more. Twist-on connectors, however, aren't typically used on wiring thicker than AWG #10, as solid wire like this is too stiff to be used with this type of connector.

These connectors are for use with solid wire only, as stranded wire will not connect securely in the ports of the connector. As the name suggests, the connection is made by pushing the solid wire into the connector until it sits tightly in place. Start by using a wire stripper or crimper to remove about ½" of the wire's insulation. Now simply push the stripped wire into one of the ports (these connectors are available with anywhere from 2 to 4 ports depending on your wiring requirements). Be sure the wire is inserted deep enough into the connector so that if you give it a good tug it won't easily come back out. 

Push-in connectors have a clear shell allowing you to see if the connection was made tightly. Additionally, the clear shell makes it easier to spot a loose connection during repairs, and because of its small size, they fit easily within junction boxes. To remove a wire from a reusable push-in connector, simply hold the connector in one hand and, using a slight twisting motion, pull the wire away from the connector with your other hand.

Typically made of steel or copper, crimp-on wire connectors require a crimping tool to make the correct connection. To use, strip the wires to be connected, align them alongside each other, and then twist the two ends together. Now, slide the crimp-on wire connector over the wires and use the crimping tool to ensure a tight, secure connection.

Since these connectors are firmly crimped in place, the connection is designed to be permanent, unlike the twist-on or push-in connectors. If a change needs to be made to the wiring or the crimp-on wire connectors do need to be removed, they would have to be completely cut off using a wire cutter.

While they're easy to use and small in size, electrical wire connectors can provide a big assist when it comes to ensuring your wiring job is done correctly and safely.

The product statements contained in this guide are intended for general informational purposes only. Such product statements do not constitute a product recommendation or representation as to the appropriateness, accuracy, completeness, correctness or currentness of the information provided. Information provided in this guide does not replace the use by you of any manufacturer instructions, technical product manual, or other professional resource or adviser available to you. Always read, understand and follow all manufacturer instructions.