Installing a New Home Circuit and Breaker
How to Install a Circuit for a New Room
When wiring a new room in your house, you will find yourself tasked with installing a new circuit as well as a breaker switch.
This type of project can be done by the homeowner, but it will take prior knowledge of construction remodeling, a variety of home improvement tools, attention to detail, and the employment of electrical safety precautions. If you are in any way unsure of your abilities to perform the following steps, stop what you’re doing and call a professional electrician immediately. Improper installment or messy work could not only be a burden on your wallet, but a legitimate safety hazard to your family and you.
Steps to Installing the Circuit:
First and foremost, make sure that your breaker panel can handle the installation of a new circuit. You will have to inspect your panel’s main breaker to check the amperage rating. This rating shows the total current that each the two columns of breakers can handle at once.
- Take measurements of the room(s) where you will be installing a circuit. Create a floor plan and mark the positions of the outlets, switches, light and fan fixtures, and major appliances that you plan on having.
- Draw out plans for the electrical cable that will be running from the circuit breaker panel to the devices within the circuit.
- To figure out the total load of the circuit you will be installing, add up the wattage for every device on the new circuit. From there you can determine what kind of circuit breaker you will need to install. You will have to look into the circuit breaker safe load capacity ratings to discover what is best for your circuit. (NOTE): If the load is greater than 1,920 watts, you will need to install two circuits.
- Select the electrical boxes needed for your switches, outlets, and fixtures. Different electrical boxes have different functions, so you will need to do some research into which boxes will suit your needs. Turn off the power in your home (via the main breaker in your panel) and begin installing the electrical boxes as you have outlined on your floor plan. This is as simple as hammering nails into wall studs or ceiling joists.
- Follow your circuit plan once again to begin running cables between electrical boxes. Working in an unfinished room means you will have to drill holes into the studs to run the cable through (ideally in a straight line) a foot above your receptacles. Secure the cable using cable staples. To protect your cables from being accidentally drilled into in the future, make sure to install metal nailing plates to the framing members where the cable passes through.
- Now run the cable from your circuit’s first electrical box to your circuit breaker panel, but do not wire them together just yet. Instead, focus on the wiring of each electrical box to the outlet, switch or fixtures as detailed in your plan.
- Confirm that the main breaker switch is set to off in your breaker panel. If you have a separate main disconnect near the meter on the outside of your home, make sure that is off as well.
- Take off the screws of the panel breaker cover and remove it. Find the knockout slug located on the side of the panel and remove that as well.
- Into the now open knockout, insert a cable clamp and begin using a cable ripper to remove a foot of sheathing from the end of your cable. Push the cable through the clamp until there is about a half inch of covered cable inside the panel. Tighten the clamp to secure placement.
- To begin wiring the new circuit breaker, place the end of the copper grounding wire into one of the setscrew terminals in the grounding bus bar and tighten it. Connect the grounding wire to the neutral bus bar if there is no separate grounding bar. Make sure that the excess part of the grounding wire is running along the edge of the panel and away from the bus bars.
- If you’re using 120-volt circuits, remove a half inch of sheathing from the white neutral wire and insert it into an open terminal on the neutral bus bar. Then strip a half inch from the black hot wire, the end of which goes into the new circuit breaker’s terminal. Tighten all setscrews. Next, lock the new breaker into an open slot by inserting the side with the hot wire attached under the tab near the hot bus bar, and push in the other side towards the bus bar. It should snap into place. Excess wiring should be positioned along the inside edge of the panel so they won’t touch the bus bars.
For 240-volt circuits, simply remove a half inch of sheathing from the ends of the hot wires and insert them into a terminal onto the new breaker. Tighten the setscrews and position the rest of the wires so they aren’t touching the bus bars.
- Remove the knockout on the panel cover that matches to your new circuit breaker.
- Replace the cover back on the panel and secure the screws. Switch all of your circuit breakers to the off position, and then switch on the main breaker. One at a time, begin switching back on the rest of the breakers, including the one that corresponds with your new circuit.
After the installation, test your new circuit by inspecting whether electricity is being delivered to every outlet, fixture and switch. If you did the job right, they should all be functioning. If you experience any problems during the course of your project, or the circuit does not seem to be working after installation, contact a certified electrician to perform troubleshooting.