How to Install Electrical Junction Boxes

electrical boxes mounted to a brick wall
  • 1-2 hours
  • Intermediate
  • 15-30
What You'll Need
Junction box
Flathead screwdriver
Phillips screwdriver
Hammer
Wire stripper
Wire nuts
Knife
Electrical tape
What You'll Need
Junction box
Flathead screwdriver
Phillips screwdriver
Hammer
Wire stripper
Wire nuts
Knife
Electrical tape

If you do any electrical work on your house, you’ll be installing electrical junction boxes. When you’re joining wires you need to use electrical junction boxes in order to comply with electrical codes. Never just connect wires with wire connectors outside a junction box. It’s not difficult to install electrical junction boxes. With just very basic electrical knowledge you can make a success of the job. Simply follow the instructions and you’ll see that it will all go very smoothly.

Step 1 - Evaluate the Size

The size of your electrical junction boxes will be determined by the size of the wires you need to join. Go to your local hardware store and you’ll see they stock many different sizes of junction box. Make sure that you also buy a cover for your junction box as this will add an extra level of safety.

Step 2 - Put in Place

electrical box full of wires in the wall

Decide where you need to put the electrical junction boxes. You’ll see that there are nails in the side of the junction boxes. You can use these to hammer the junction box in place on the side of a stud. You’ll see circles on the sides of the electrical junction boxes. These can be knocked out for the wires to enter. Use a flathead screwdriver and hammer to knock out these holes as you need them. You’ll find that they remove very easily.

Step 3 - Wires

Pull the wires you need to connect into the electrical junction boxes through the holes you’ve made. Allow six inches of wire to hang out of the box and then cut off any excess wire with your knife. You want ample wire so you can work easily, but not an excess.

Using your knife, cut the sheathing on the wires so that you expose the individual wires. These will be wrapped in their insulation. There should be three wires in each cable. Use the wire strippers to remove ½ inch of insulation from the tip of each of the wires. One of the wires will be black, the second white or silver, and the third green. Instead of green, it might just be a bare copper wire.

Step 4 - Connect

electrical wiring box

To connect the wires, take the two black wires and twist the exposed ends together. Cover with a wire nut, making sure it’s firm on the wires. After this, cover the wire nut with electrical tape. Do the same with the wires with white or silver insulation, and then with the ground wire, which is the one with the green insulation or just the bare wire. Always cover the connections with wire nuts and finish with electrical tape.

Push the wires into the electrical junction boxes and then screw covers on the electrical junction boxes. Although this is something most people don’t bother to do it adds an extra layer of safety.