AFCI/GFCI Combo Breaker Symbol
Definition: The AFCI/GFCI Combo Breaker symbol represents a dual-protection circuit breaker that combines Arc-Fault Circuit Interrupter (AFCI) and Ground-Fault Circuit Interrupter (GFCI) functions in a single panel-mount device, shown in wiring diagrams with Line and Load terminals to indicate a circuit protected from both arc-fault-caused electrical fires (per UL 1699) and ground-fault electrical shock hazards (5mA trip threshold, per UL 943), as required by ANSI/NFPA 70 (NEC) for circuits where both protections are mandated.
Also known as: AFCI/GFCI breaker, dual protection breaker, CAFCI/GFCI breaker, combo AFCI GFCI, AFCI+GFCI circuit breaker, arc-fault ground-fault breaker, dual function circuit breaker.
What the AFCI/GFCI Combo Breaker symbol means
The AFCI/GFCI Combo Breaker symbol marks a panel position in a wiring diagram where a single breaker provides two independent safety functions: arc-fault protection detecting the high-frequency current signatures of dangerous arcing (preventing electrical fires) and ground-fault protection interrupting the circuit when leakage current exceeds 5mA to ground (preventing electrocution). This single device satisfies two NEC code requirements simultaneously, simplifying panel design in circuits such as kitchen and bathroom branch circuits where both AFCI and GFCI protection are required.
In panel schedules, the AFCI/GFCI Combo Breaker symbol — typically annotated 'AFCI/GFCI', 'DF' (Dual Function), or 'AF+GF' — identifies circuits where both hazard types must be addressed. The symbol distinguishes this device from an AFCI-only breaker, a GFCI-only breaker, and a standard circuit breaker, each of which provides only a subset of the total protection.
How to identify the AFCI/GFCI Combo Breaker symbol
The AFCI/GFCI Combo Breaker symbol is drawn as a standard circuit breaker rectangle with both 'AFCI' and 'GFCI' annotations, or a single label 'AFCI/GFCI' or 'Dual Function'. Line and Load terminals are shown. Some schematic conventions show a wave symbol (arc), a ground symbol, and a person-in-box symbol (shock hazard) to indicate both functions. In panel-layout drawings the physical breaker face is typically labelled 'DUAL FUNCTION ARC FAULT & GROUND FAULT CIRCUIT INTERRUPTER' per UL listing requirements.
Function in a circuit
The AFCI/GFCI Combo Breaker integrates two electronic monitoring circuits around a single set of circuit contacts. The AFCI module monitors both series arcs (loose connections, damaged wire insulation) and parallel arcs (wiring faults between conductors), tripping the breaker when arc signatures are detected within 1–2 AC half-cycles. The GFCI module continuously measures the difference between the hot and neutral conductor currents; if the difference exceeds 5mA (indicating current leaking to ground through a person or fault path), the breaker trips within 25 milliseconds to prevent electrocution. Both monitoring functions operate simultaneously and independently; either condition alone will trip the breaker.
Standards: IEC vs ANSI
| IEC 60617 | IEC 62606 covers AFDD (Arc Fault Detection Devices) and IEC 61008 / IEC 61009 cover RCDs (Residual Current Devices, the IEC equivalent of GFCI). A combined AFDD+RCD device is emerging in IEC markets. IEC-style schematics label such a device with both AFDD and RCD symbols or a combined annotation. |
|---|---|
| ANSI/IEEE 315 | UL 1699 lists AFCI performance requirements; UL 943 lists GFCI performance requirements (5mA Class A trip threshold). The combined device is listed under both standards. ANSI/NFPA 70 (NEC) Article 210.12 mandates AFCI and Article 210.8 mandates GFCI; the combo breaker satisfies both articles. Schematic symbols follow ANSI Y32.2 / IEEE 315-1975 breaker conventions. |
| Key difference | IEC markets address these as separate devices (AFDD + RCD) rather than one combined unit, though combined products are increasingly available. North American NEC practice has standardised on the integrated AFCI/GFCI combo breaker as a space-saving solution. Symbol annotation differs (AFDD+RCD vs AFCI/GFCI) but both represent the same dual-protection function. |
Terminals / pins
| Pin | Name |
|---|---|
| line | Line |
| load | Load |
Typical values
Standard ratings: 15A and 20A, 120V AC (residential branch circuits). GFCI trip threshold: 4–6mA (Class A per UL 943). GFCI trip time: ≤25ms at 5mA. AFCI series arc detection: typically arcs ≥8A. Interrupt capacity: 10,000A AIC standard. Neutral pigtail wire included. Test button verifies both AFCI and GFCI functions.
Where the AFCI/GFCI Combo Breaker symbol is used
- Kitchen branch circuits in new construction (≥15A, 120V) requiring both AFCI per NEC 210.12 and GFCI per NEC 210.8(A)(6)
- Bathroom circuits requiring both GFCI protection (NEC 210.8) and AFCI protection (NEC 2020)
- Laundry room branch circuits in new construction where both protections are mandated
- Garage circuits where both GFCI (wet/damp location) and AFCI (habitable attached space) are required
- Outdoor circuits feeding receptacles in areas where both arc-fault and shock hazard risks are present
- Finished basement circuits in new construction under NEC 2020 requirements for both AFCI and GFCI
- Retrofit panel replacements where a single breaker satisfies two code requirements without adding a GFCI receptacle
Example
In a kitchen remodel wiring plan, the AFCI/GFCI Combo Breaker symbol is shown on two 20A branch circuits feeding the countertop receptacle outlets; each breaker's Line terminal connects to the 120V bus bar and the Load terminal feeds 12 AWG/2-conductor Romex, with the white pigtail connecting to the neutral bus bar — a single symbol confirms that both NEC 210.8(A)(6) GFCI and NEC 210.12 AFCI requirements are satisfied by one panel device, simplifying the panel schedule.
Key facts
- The AFCI/GFCI Combo Breaker symbol represents a single circuit breaker providing both arc-fault detection (AFCI) and ground-fault protection (GFCI 5mA trip) simultaneously, satisfying two NEC code requirements with one panel space.
- AFCI function detects series and parallel arc-fault current signatures and trips the breaker within 1–2 AC half-cycles to prevent electrical fires.
- GFCI function monitors the current difference between hot and neutral conductors and trips in ≤25ms when leakage exceeds 5mA (Class A per UL 943) to prevent electrocution.
- The combined device is listed under both UL 1699 (AFCI) and UL 943 (GFCI), satisfying both ANSI/NFPA 70 (NEC) Article 210.12 and Article 210.8 requirements.
- A white pigtail neutral wire connects from the breaker to the neutral bus bar — required for both the AFCI detection circuit and the GFCI differential current monitoring.
- The test button on AFCI/GFCI combo breakers tests both the arc-fault detection and the ground-fault detection circuits; pressing it should trip the breaker.
- The symbol is drawn per ANSI Y32.2 / IEEE 315-1975 as a circuit breaker block with 'AFCI/GFCI' or 'Dual Function' annotation, with Line and Load terminal pins.
Frequently asked questions
What does the AFCI/GFCI combo breaker symbol mean on a wiring diagram?
The AFCI/GFCI combo breaker symbol means a dual-function circuit breaker is required at that panel position, providing both arc-fault protection (detecting dangerous arcing that causes electrical fires) and ground-fault protection (tripping at 5mA leakage current to prevent electrocution). One device satisfies two NEC safety requirements simultaneously.
What does the AFCI/GFCI combo breaker symbol look like?
The AFCI/GFCI combo breaker symbol is a standard circuit breaker rectangle labelled 'AFCI/GFCI', 'Dual Function', 'AF+GF', or 'CAFCI/GFCI'. It shows Line and Load terminals. In panel schedules it is distinguished from AFCI-only, GFCI-only, and standard breakers by the combined annotation. Physical breakers are labelled 'DUAL FUNCTION ARC FAULT & GROUND FAULT CIRCUIT INTERRUPTER'.
What is the difference between an AFCI breaker and an AFCI/GFCI combo breaker?
An AFCI-only breaker detects arc-fault signatures to prevent fires but does not provide personnel shock protection. An AFCI/GFCI combo breaker adds 5mA ground-fault protection on top of the arc-fault detection, tripping the circuit if current leaks to ground through a person or fault path. The combo breaker is used on circuits where both hazards must be addressed per NEC code.
Where are AFCI/GFCI combo breakers required by the NEC?
ANSI/NFPA 70 (NEC) requires AFCI on most habitable room circuits (Article 210.12) and GFCI on circuits near water sources — bathrooms, kitchens, garages, outdoor outlets, crawl spaces, unfinished basements, and boathouses (Article 210.8). Any circuit where both requirements overlap — such as kitchen countertop or bathroom circuits in new construction — requires either an AFCI/GFCI combo breaker or separate AFCI breaker plus GFCI receptacles.
How many terminals does the AFCI/GFCI combo breaker symbol have?
The AFCI/GFCI combo breaker symbol shows two power terminals: Line (hot bus bar in the panel) and Load (branch circuit hot wire). The physical device also includes a white pigtail wire connecting to the neutral bus bar — this pigtail is essential for both the GFCI differential current monitoring and the AFCI detection circuitry.
What standards govern the AFCI/GFCI combo breaker?
The AFCI/GFCI combo breaker is listed under UL 1699 (Arc-Fault Circuit-Interrupters) and UL 943 (Ground-Fault Circuit-Interrupters, Class A, 5mA trip). Usage is mandated by ANSI/NFPA 70 (NEC) Articles 210.8 (GFCI) and 210.12 (AFCI). The IEC equivalents are IEC 62606 (AFDD) and IEC 61008/61009 (RCD/RCBO).
Can one AFCI/GFCI combo breaker protect multiple outlets on the same circuit?
Yes. An AFCI/GFCI combo breaker installed at the panel protects the entire branch circuit, including all outlets, receptacles, and devices downstream of the breaker. This is equivalent to installing a GFCI receptacle at the first outlet and wiring all subsequent outlets as 'protected by GFCI', but the combo breaker approach requires no GFCI devices in the walls and protects the full circuit wiring including the feeds from the panel.
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