How to Wire a New Garage

Check the main circuit box to see if there is sufficient space to install a dedicated 20-amp circuit for the new garage. Hire a qualified electrician to install the new circuit and run a feed line out to the garage. Switch the new circuit off before beginning with the garage wiring.

Draw out a plan for the location of lights, switches and electrical outlets in the new garage. This helps determine the right area for each item and shows quantities needed. Plan for at least four outlets in the garage, but add more if it is a very large garage. Take into account the major areas where power is needed. Place outlets approximately every 6 feet to allow for convenient reach.

Connect the main feed line from the main house to a small electrical breaker box in the garage. This makes it easy to install all the different wiring needs to one convenient location and cut the garage power quickly if necessary. Put it in an easy to reach, but out of the way location.

Mark the location with a pencil onto the exposed stud wall where everything belongs. Attach plastic switch and outlet boxes in the locations desired. These have nails already in them, so you just need to position them where you want them and hammer the nails into the studs. Mount the light fixtures to the ceiling joists at the same time.

Drill 3/4-inch diameter holes through the wide part of the stud just above the switch or outlet box and then continue drilling holes until you reach the breaker box. Run a standard, residential-rated electrical cable starting at the breaker all the way through the stud wall until you reach the box. For light fixtures, drill holes through the ceiling joists, down one wall and then through studs.

Wire the switches and outlets with the main wire. Feed them down into the box, then strip the insulation off the individual wires with wire strippers. Bend the end of the thick copper black wire with pliers, wrap it around the copper screw and tighten the screw down with a screwdriver. Do the same to the white wire and the silver screw.

Wrap the entire outlet or switch with electrical tape to cover the connections. Screw the outlet unit or switch into the pre-drilled holes of the plastic box to hold it firmly in place.

Wire light fixtures by closely following the manufacturer's instructions. In most cases, there are simply white and black wires attached to the fixture for linking with the main electrical wire. Strip the insulation off the wires, use wire nuts to connect the wires to the light and wrap the connections thoroughly with electrical tape.

Connect the individual wires to the garage breaker box. Be sure the house's main circuit box and the garage box's main switches are both off before doing this. Strip a length of insulation off of each wire and connect the individual black and white wire to a circuit. These connections are similar to the ones made for the outlets. Wrap all joined wires with electrical tape so that no wire is visible.

Turn the power on to the garage at the main house circuit box, and then turn the main switch on at the garage box. Test the lights, switches and each individual outlet to ensure they work correctly.