How to Wire a 30 Amp Breaker Box

Put on the safety glasses. Go to the main breaker panel and find the end of the number eight or larger electrical cable intended to feed to the 30-amp breaker box. Check that it is not connected to a power source or that its breaker is in the off position.

Go to the 30-amp breaker box being installed. Use the screwdriver to remove the screws from the cover. Lift off the cover. Turn the switch on the 30-amp breaker to the off position. Unplug the breaker by pulling it from the box and set it aside.

Look into the 30-amp breaker box and see the two large insulated main screw connectors mounted near the top inside. Place the number eight or larger feeder cable from the main panel through one of the holes in the box and leave enough slack to reach the two top screw connectors.

Use the razor knife to cut the outer insulation from the feeder cable without damaging the insulation on the wires. Separate the bare ground wire and place its end under any screw on the ground bar in the 30-amp breaker box and tighten it using the screwdriver.

Strip one-half inch of insulation from the red and black wires feeding from the main panel using the electrician's pliers. Connect the red wire to either of the top insulated screw connectors in the 30-amp breaker box by placing the end of the wire under the screw and tightening it using the screwdriver. Connect the black wire to the other top screw in the same manner.

Place the No. 10 cable that feeds from the new 30-amp breaker box through any hole in its bottom leaving enough slack to reach the ground bar. Remove the outer insulation from the end of the cable by using the razor knife. Separate the bare ground wire inside the cable. Place the end of it under any screw on the same ground bar as the ground wire from the main feeder cable was placed. Tighten the ground screw using the screwdriver.

Strip one-half inch of insulation from the red and black wires of the cable feeding from the new 30-amp breaker box using the electrician's pliers. Hold the 30-amp breaker in one hand and using the other, place the end of the black wire under either screw located on the bottom end of the breaker. Place the end of the red wire under the other screw located on the bottom end of the breaker.

Tighten the screws using the screwdriver. Place the breaker in its position in the 30-amp breaker box and plug it in by pushing against it until it snaps into place.

Go to the main breaker box. Find the end of the number eight electrical cable intended to feed to the 30-amp breaker box. Connect its bare ground wire to the ground terminal strip. Strip one-half inch insulation from the end of its red and black wires.

Place the end of the red wire under either screw on the bottom of the 30-amp or larger breaker intended to feed the new 30-amp breaker box. Place the black wire under the other screw on the bottom of the same breaker. Tighten the screws using the screwdriver.

Place the breaker in its position in the main breaker box and plug it in by pushing against it until it snaps into place. Leave the switch on the feeder breaker in the main panel box in the off position until all electrical work on the new 30-amp circuit is completed.