How to Wire an AFCI Breaker? . AFCI (Arc-Fault Circuit Interrupter) breakers are essential components of modern electrical systems. They prevent electrical fires by detecting dangerous arc faults, making them a crucial safety feature for homes and businesses. Wiring an AFCI breaker may seem daunting, but with the right tools, knowledge, and safety measures, it can be a straightforward task.
What is AFCI Breaker?
AFCI is the short version of “Arc Fault Circuit Interrupter” and also known as AFDD “Arc Fault Detector Device” or simply Arc Fault Breaker.
Arc Fault Circuit Interrupter (AFCI) is a protective device which detects the electric arc in the circuit and automatically break the circuit (cutoff power supply) to prevent electrical fire.
The ordinary circuit breaker won’t sense and operate that quickly during the initial stage of producing arc in the circuit. As these normal circuit breakers only respond to a specific amount of heat, not quick surges, that’s why AFCI are used to prevent the electric fire in the circuit.
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The 2017 NEC (National Electrical Code) now requires the AFCI protection in almost all new construction such as bedrooms, living rooms, dining rooms, family rooms, kitchen, libraries, closets, libraries, laundry rooms, dens and other similar areas in a residential area. In short, All the single phase 120V, 15A and 20A branch circuits and outlet receptacles providing power supply must be protected by Arc Fault Circuit Interrupter breakers.
According to 2014 NEC, OBC (Outlet Branch Circuit) AFCI breaker or AFCI receptacle / outlet can be used to protect the circuit under various conduction. The OBC AFCI breaker and outlet will provide protection against both series (in single wire) and parallel (between two wires)
Keep in mind that GFCI will not interfere with AFCI i.e. A ground fault circuit interrupter can be used and installed downstream to the arc fault circuit Interrupter. In Short, GFCIs can be wired with AFCIs in a circuit. In addition, GFCI protects against electric shock due to ground faults currents while AFCI protects against electrical fires in the circuits due to electric arcs.
Tools and Materials Needed
Before beginning the wiring process, gather the following tools and materials:
- AFCI breaker
- Screwdrivers (flathead and Phillips)
- Wire strippers
- Voltage tester
- Electrical tape
- Needle-nose pliers
- Safety gloves and goggles
- Circuit labels
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Now, we will learn how to wire and install a single pole and two pole ground fault circuit interrupter circuit breakers in home.
Wiring a Single Pole AFCI Circuit Breaker
The following wiring shows two outlet receptacles has been wired and protected through single phase single pole AFCI circuit breaker.
As shown in the fig, the built in white wire on the back side of arc fault circuit interrupter circuit breaker has been directly connected to the neutral busbar in the main board. Keep in mind the AFCI wont work and protect the circuit if we don’t connected the white wire to the incoming neutral bar in the main distribution board.
The Line (Hot, Live or Phase) is directly connected to the AFCI input from main supply. The lower load terminals i.e. Hot and Neutral has been connected to the Line and Neutral terminals of both standard outlets. The ground wire is also connected from ground busbar to the receptacles ground terminals as shown in fig.
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The illustrated wiring will protect the single phase 120V, 15 amperes outlets from arc faults by 30 amp AFCI circuit beaker. For 15 amp circuit, use 14 gauge wire while for 20 amp circuit, you may use 12# gauge wire size.
The same wiring can be done for 230V, 13A circuit using the correct wire size, proper circuit breaker rating and suitable rating of switches and outlets.
Special Notes:
- To avoid false tripping operation, do not install and wire an AFCI, GFCI, GFPE (Ground Fault Protection of Equipment) or Combo of both AFCI/GFCI circuit breakers on shared Neutral wire with other circuits.
- OBC AFCI (Outlet Branch Circuit Arc Fault Circuit Interrupter) can be used on all types of electrical wiring installation for both series and parallel arc quenching.
- It is not necessary to add AFCI protection devices on circuit extensions of less than 6′.
- A special device as combo of AFCI/GFCI can be used for both ground fault leakage currents and arc protection.
Wiring a Two Poles AFCI Circuit Breaker
The following wiring shows an electric stove, range or dryer has been wired and protected through a twp pole AFCI circuit breaker.
As there is no need of Neutral wire in 240V single phase supply but some 240V single phase appliances are needed to be wired with the neutral wire as well such as hot tub spa and dryer etc. The wiring should be followed by the manufacturer user manual guide and a licensed electrician.
In this four wire AFCI wiring diagram, two lines as L1 and L2 has been connected to the input terminals of AFCI breaker and the builtin white is connected to the neutral busbar in the mains supply.
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The three load terminals of AFCI breaker is directly connected to the electric stove control box panel following the sequence as Line 1 (Red), Neutral (Black in the middle) and Line 2 (Blue). The ground / earth wire (as green) is connected to the ground terminal from ground busbar. This way, the connected device is AFCI protected.
Safety Precautions
- Switch off the main circuit breaker to make sure the power supply is OFF before wiring a GFCI outlet.
- Use the suitable voltage and ampere rating of switch with appropriate wire size and proper size MCB according to the load rating.
- Use the correct polarity i.e. verify the Load and Line terminals while installing a GFCI for protection. In other words, connect the wires to the correct side of outlet for proper operation.
- Regular maintenance, check and test is recommended while test the portable GFCI before each operation.
- Contact the authorized and licensed electrician for GFCI installation if you are not sure about the wiring diagrams.
- We have used Red for Hot or Line 1, Blue for Line 2, Black for Neutral and Green for Ground for illustration purpose only. Follow your own area wiring color codes according to NEC, IEC etc.
- The author will not be liable for any losses, injuries, or damages from the display or use of this information or if you try any circuit in wrong format. So please! Be careful because it’s all about electricity and electricity is too dangerous.
Common Mistakes to Avoid
- Incorrect Wiring: Mixing up hot and neutral wires can lead to malfunction.
- Overloading the Circuit: Ensure the circuit’s load does not exceed the breaker’s rating.
- Loose Connections: Tighten all screws and terminals securely.
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Installing an AFCI Breaker
Installing a one-pole, 15-amp AFCI (arc-fault-circuit-interrupter) breaker is exactly the same as installing a one-pole GFCI (ground-fault-circuit-interrupter) breaker. But before we see how to install one, here is a quick refresher about how each of these code-required devices protects you.
AFCI breakers are designed to detect arcing patterns of current in very short time intervals—such as when there is a loose connection on a receptacle and electricity arcs (jumps) between conductors. Drywall nails or screws puncturing a cable are other common causes of arc faults. When an AFCI breaker detects such patterns, it shuts off power to protect you from house fires.
GFCI breakers are designed to sense an imbalance between the amount of current flowing from the hot wire and returning on the neutral wire, which suggests a ground-fault current is leaking to ground somewhere. GFCIs can detect minuscule (5 milliamp) current leaks and shut off power almost instantaneously—typically within 1⁄40 second—to protect people from potentially fatal shocks.
Always turn off power to a panel and test to be sure it’s off. After pulling the new circuit cable into the subpanel, the electrician secured it with a cable connector and stripped its sheathing, as described above. As is customary, he first terminated the cable’s bare ground wire to the ground bus.
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Every AFCI (and every GFCI) breaker has a coiled neutral conductor that is molded into the breaker at the factory. After snapping the AFCI breaker onto a hot bus, the electrician attached that coiled neutral to the neutral bus 1. The electrician then stripped 3⁄8 in. to 1⁄2 in. of insulation from the end of the circuit-cable neutral and terminated it to the AFCI breaker lug, designated by a small white dot next to it 2. Note: Most circuit neutral wires terminate to a neutral bus. But here the circuit neutral attaches to the breaker so it can sense fluctuations in current throughout the circuit.
1) Terminate the circuit ground wire. Then terminate the coiled, factory-attached white wire of the AFCI breaker to the neutral bus.
2) Next, terminate the circuit neutral to the neutral lug on the AFCI breaker. A small white dot on the breaker indicates the neutral lug.
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Finally, the electrician stripped insulation from the end of the circuit hot wire and attached it to the remaining breaker lug 3. He used a multimeter to test for a dead short in the circuit. Finding nothing out of the ordinary, he removed a breaker knockout from the subpanel cover, replaced the cover, and energized the subpanel. Then he flipped the AFCI breaker on and pressed the white TEST button on the face of the breaker. The TEST button should snap off immediately; if it doesn’t, the breaker is probably defective and should be replaced immediately. Inspectors are very serious about AFCI protection, so always test AFCI breakers after installing them—even if they are right out of the box.
3) Terminate the circuit hot wire to the hot lug on the AFCI breaker.
Advantages of Using AFCI Breakers
AFCI breakers offer significant benefits:
- Fire Prevention: Reduces the risk of electrical fires.
- Enhanced Safety: Protects vulnerable areas like bedrooms and living rooms.
- Code Compliance: Meets modern building and safety standards.
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FAQs
1. What is the purpose of an AFCI breaker?
An AFCI breaker prevents electrical fires by detecting and interrupting dangerous arc faults.
2. Do all circuits require AFCI breakers?
Building codes vary, but AFCI breakers are often required in living areas, bedrooms, and common spaces.
3. Can I install an AFCI breaker myself?
Yes, if you have basic electrical knowledge. However, consult a professional for complex installations.
4. How do I test my AFCI breaker?
Press the test button on the breaker. It should trip and then reset without issues.
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