This article shows you how to wire a 30-amp single-pole circuit breaker.
A 30-amp circuit breaker is usually a double-pole, but it also comes as a single-pole breaker for a 110-volt supply on a 10/2 circuit. The procedure is similar to wiring a regular 15- or 20-amp circuit breaker.
The wiring part of the procedure to wire a regular 30-amp single-pole circuit breaker involves connecting the bare wire to the grounding bar, the white wire to the neutral bar, and the hot wire directly to the breaker.
However, if it’s a GFCI or AFCI breaker, connect the white wire to the silver terminal on the breaker itself, the black wire to the brass terminal on the breaker, the extra pigtail neutral wire to the neutral bar in the panel, and the bare wire to its ground bar.
I’ve also briefly introduced the 30-amp breaker, listed all the requirements, and mentioned safety precautions and how to test the breaker for power.
30-Amp Single-Pole Circuit Breakers
A 30-amp single-pole circuit breaker looks similar to a regular circuit breaker with fewer amps.
However, it is designed to cope with a larger load, which means a higher current, up to a maximum of 24-30 amps (or 2,880 watts of power). It is normally used for a heavy appliance that requires 110-120 volts to operate, not 220-240 volts, for which you will need a double-pole breaker instead.
Also, it should only be fitted on a circuit with at least 10 gauge (10/2) wiring (8 gauge for long distances). Don’t attempt to use it on circuits with thinner wire or to replace a circuit breaker with fewer amps.
Requirements
You will need the following to wire a 30-amp single pole circuit breaker:
- Main item: A 30-amp single-pole circuit breaker
- Tools: Electrical tester or screwdriver, pliers, and a wire stripper
- For testing: Voltmeter or multimeter
- For safety: safety gloves and rubber slippers or mat
The procedure described below assumes that your panel has enough capacity and space for a 30-amp circuit breaker.
If you’re replacing an existing one, you will remove it in Step 3 before replacing it with the new one.
If you install a new 30-amp circuit breaker, ensure the wiring and all outlets on its circuit can handle up to 30 amps of current.
Wiring a 30-Amp Single-Pole Circuit Breaker
Here are the steps to wire a regular (non-GFCI/AFCI) 30-amp single-pole circuit breaker:
Step 1: Lay the Mat
Lay the rubber mat, wear rubber slippers, and only work with dry hands and tools.
Step 2: Turn the Power Off
Remove the main panel’s cover and turn the main power switch to the panel off.
The main breaker is normally separate from the rest, either at the very bottom, top, or to one side. It’s also normally the largest one, rated for the highest amps.
It’s important that you turn it off to minimize the risk of working with live wires.
Step 3: Check the Power
Although you turned the main switch off, checking the power is wise to ensure it’s off.
Set the multimeter to AC volts. The red probe should be plugged into the V port, and the black one into the COM port.
If you’re replacing an existing 30-amp circuit breaker, remove it first. Touch the black probe to the neutral or ground bar and the red probe to the screw terminal where you install the circuit breaker.
The reading should be close to zero volts because you turned the power off. The normal current is still flowing if it shows 110 volts or more. Ensure the power is disconnected. Call an electrician if you’re sure the main switch is off, but there’s still power.
Step 4: Set the Breaker
Ensure the new circuit breaker’s switch is in the OFF position.
Set it in position by sliding the breaker into the groove, and push it gently until it snaps into place.
Step 5: Prepare the Wire
The wire ends might already be stripped, especially if used previously.
But if not, use the wire stripper and strip about ½” of the insulation from each end to expose the bare copper.
If it’s a new cable, cut the outer sheathe about an inch from the top, as shown in the picture below.
Step 6: Connect the Wires
Insert the load’s wires into their respective terminals and tighten the screws.
Connect the three wires as follows:
- Connect the ground (bare copper) wire to the grounding bar and screw it tightly.
- Connect the neutral (white) wire to the neutral bar and screw it tightly.
- Connect the hot (black) wire directly to the circuit breaker and screw it tightly.
The hot (black) wire should be long enough to reach the breaker easily. If you need to cut its end, ensure it has sufficient length.
Ensure that all three terminal screws are tight.
Step 7: Switch the Power On
With the wiring of the 30-amp circuit breaker now done, switch the power back on.
Switch the circuit breaker on and also the main panel’s switch.
If the circuit breaker has a test button, you can press it to test its ability to trip. Switch it back on again after testing and close the main panel.
Step 8: Re-Test the Power
The appliance connected to the circuit with the 30-amp breaker should be working.
The circuit breaker is operating normally if it is, but if not, repeat Step 3 only to check the power to the new circuit breaker.
The reading should be 110-120 volts. If it’s close to zero volts, a screw might be loose, or the breaker might be faulty. Also, ensure there’s no power outage (other appliances in the home should be on). If you suspect a faulty circuit breaker, return it to the store for a replacement.
Wiring a 30-Amp GFCI/AFCI Circuit Breaker
If you have a GFCI or AFCI 30-amp single-pole circuit breaker, the procedure is similar, but it will come with an extra white pigtail (coiled) wire, and you attach the white wire directly to the breaker as well (like the black one).
It will look similar to the one shown in the picture below.
Before wiring it, follow all the initial safety and preparation steps described for the regular breaker above.
Connecting the Wires
Proceed as follows when connecting the wires and before setting the breaker into its place inside the panel:
- Connect the neutral (white) wire to the silver screw on the breaker and screw it tightly.
- Connect the hot (black) wire to the brass screw on the breaker and screw it tightly.
- Set the breaker in its place inside the panel.
- Connect the extra neutral (white pigtail) wire to the neutral bar and screw it tightly.
- Connect the ground (bare copper) wire to the grounding bar and screw it tightly.
Step 1: Connect the Neutral Wire
Connect the neutral (white) wire to the silver screw on the breaker and screw it tightly.
Step 2: Connect the Hot Wire
Connect the hot (black) wire to the brass screw on the breaker and screw it tightly.
Step 3: Set the Breaker
Set the breaker in its place inside the panel, as shown below.
Step 4: Connect the Pigtail Wire
Connect the extra neutral (white pigtail) wire to the neutral bar in the panel and screw it tightly.
Step 5: Connect the Bare Wire
Finally, connect the ground (bare copper) wire to the ground bar and screw it tightly.
That’s it. You can also test the GFCI/AFCI breaker similarly if necessary, but remember to connect the red probe to the hot (black) wire’s brass terminal.
References
30-amp single-pole circuit breaker. https://www.lowes.com/pd/Square-D-QO-30-Amp-1-Pole-Standard-Trip-Circuit-Breaker/3129463
Video References
Circuit Breaker Wholesale
Craig Michaud-Electrical Instructor
David Berquist
Jungle Explorer
Schneider Electric
David Finch