How to Install Junction Boxes

The National Electrical Code says that no splices are allowed outside of junction boxes. It has been my experience, however, that many older homes have plenty of them around. A wire splice should always be placed in a protective box and covered with a box cover. Before correcting this problem, as with any other electrical fix, turn the power off to the circuit that you’ll be working on. This may involve turning off a circuit breaker or unscrewing a fuse. Safety should be your first concern. Use a tester to check the connection and see that it really is off before proceeding. Check for power between the hot wire and the neutral wire to see if there is any power present. Once you know the power is off, take the wire splices apart so that junction box can be added.

To install a junction box, first pull the two wires back so that the box can be added. Remove two of the box’s knockouts to allow the wires access to the box. Install cable connectors in these holes and tighten the locknut with pliers. The wire will slide into the connectors and can be tightened with a screwdriver. Now, install two screws through the small holes in the back of the box to secure the box to the wooden joist.

After the box is secure, use linesman pliers to twist the wires together. To do this, join like colors, black to black, white to white, bare copper to bare copper and twist them together evenly. Add a wire nut to cover the connection. In this case, I’m using red wire nuts to make the connections. You may want to use a green-colored wire nut on the ground (bare copper) connection to symbolize the ground connection.

Once the wires are covered, it’s time to install a cover plate. The wires must now be formed into the box so that the cover will go on effortlessly and the mounting screws don’t screw into the wire insulation. Tuck the wires into place and place the cover over the two mounting screws. Tighten the screws and you’re ready to turn the circuit back on. After restoring power, go to the device that the splice is feeding and make sure that the circuit is indeed on. If so, you have successfully installed a junction box and made your home safer in doing so.