AFCI Frequently Asked Questions

According to UL 1699, Standard for Arc Fault Circuit Interrupters, an arcing fault is an unintentional arcing condition in a circuit. Arcing is defined as a luminous discharge of electricity across an insulating medium, usually accompanied by the partial volatilization of electrodes.

There are 3 basic types of arcing faults: line-to-neutral, line-to-ground, and series arcing. More info

Arc faults may occur anywhere in the electrical system and may be a result of the following:

As defined in UL 1699, Standard for Arc Fault Circuit Interrupters, an Arc-Fault Circuit Interrupter (AFCI) is a device intended to mitigate the effects of arcing faults by functioning to de-energize the circuit when an arc fault is detected.

Siemens offers two types of AFCI: a Combination Type AFCI and a Branch/Feeder AFCI. Both types of Siemens AFCIs consist of a thermal magnetic circuit breaker with an electronic circuit board. The electronics detect the arc and activate a solenoid to trip the breaker.

The Siemens Combination Type AFCI provides protection against all three types of arcs (series, line-to-neutral, and line-to-ground). The Combination Type meets all the 1999 and later NEC® requirements. It is specifically required by the 2005 NEC® beginning January 1, 2008.

The Siemens Branch/Feeder AFCI provides protection against two types of arcs (line-to-neutral and line-to-ground). It can be used to meet the requirements of the 1999-2002 NEC® and the 2005 NEC® until January 1, 2008.

No, it only means that the device protects against all three types of arcing.  Any device that would include GFCI protection would be referred to as a dual function device.

Arcing faults generally go undetected for an extended time and can reach high temperatures even at low current levels. These temperatures can easily exceed the combustion point of common building materials.

According to the Consumer Product Safety Commission, problems in home wiring, like arcing and sparking, are associated with more than 40,000 home fires each year. These fires claim over 350 lives and injure 1,400 victims annually. And while standard circuit breakers are intended to protect conductors from overload and short circuit conditions, they do not protect against arcing faults and ground faults.

Although the AFCI and GFCI may look very similar, their purpose is quite different. AFCIs are designed to address the hazards that result from arcing, while GFCIs (Ground Fault Circuit Interrupters) are designed to address shock hazards and are intended for the protection of personnel.

No. Similar to a GFCI, you connect the neutral (pig-tail) wire to the load center neutral bar. The load wire goes to the terminal marked "LOAD POWER" and the load neutral wire goes to the terminal marked "LOAD NEUTRAL."

Yes, an AFCI does not require an equipment ground to perform its intended function. A retrofit into a home with a two wire system is an acceptable application for an AFCI. In fact, Siemens encourages the use of AFCIs in these homes as aged wiring systems also present the potential for arcing.

For the 2008 National Electrical Code®, Combination Type AFCIs are required in dwelling unit family rooms, dining rooms, living rooms, parlors, libraries, dens, bedrooms, sunrooms, recreation rooms, closets, hallways, or similar rooms or areas.

For the 2005 National Electrical Code®, Combination Type AFCIs are now required in dwelling unit bedrooms. 

Please see the NEC® for the exact wording of the requirements. Some areas may adopt other effective dates and may expand the requirements beyond the bedroom circuits. Contact your local authority having jurisdiction (AHJ) to verify code requirements for your area.  More info

For the 2005 and 2008 National Electrical Code®, a dwelling unit is a single unit, providing complete and independent living facilities for one or more persons, including permanent provisions for living, sleeping, cooking, and sanitation.

For the 2005 and 2008 National Electrical Code®, outlets are points on the wiring system at which current is taken to supply utilization equipment.

Siemens AFCI circuit breakers are designed to resist nuisance tripping when wired to a variety of loads found in the home, while keeping their full sensitivity to detect arcs. AFCIs have been tested with a wide variety of products including fluorescent lights, hand drills, welders, hairdryers, dimmers, and other appliances containing electric motors to ensure that they will not nuisance trip and to ensure that these loads would not mask the presence of an arc.

To test an AFCI, make sure there is power to the load center, or panelboard. Turn the AFCI handle to the "ON" position. Press the blue test button. Pressing the test button simulates an arc to the AFCI sensing electronics, causing the breaker to trip. The AFCI breaker is functioning properly when the circuit is interrupted and the handle moves to the tripped center position. To reset, turn the AFCI off and turn it on again. If the AFCI does not trip when the test button is pressed, it should be replaced. Refer to a qualified electrician for servicing. You should test your AFCI breaker monthly to insure protection against electrical arcing faults.

To clarify, these devices are only indicators and not "testers." Please see the attached letter from UL that addresses this issue.  Click Here

The hand-held indicators currently on the market, do not generate a genuine arc and, therefore, the only true way to verify the operation of any AFCI (Branch Feeder and Combination Type), regardless of brand, is to use the Push-to-Test button.

No. While some GFCI testers may cause an AFCI to trip, these devices are not testing the arc detection capability of the breaker. AFCIs utilize a differential sensor to detect leakage of current in a circuit. When the GFCI tester creates a leakage of current greater than the threshold level of the AFCI's differential sensor, the device will open. However, this fault detection is not intended to provide personnel protection, as the AFCI trip thresholds for differential current vary by manufacturer but are typically 30mA to 60mA – far above the 5mA level required for personnel protection. In addition, AFCIs do not specifically include grounded neutral protection. 

If a GFCI receptacle is installed on the load side of an AFCI it is possible for both the AFCI and the GFCI to trip on a ground fault if the leakage current exceeds the threshold for both devices. It is also possible for the AFCI to trip and the GFCI to not trip since the two devices could race each other. The functionality of each device should be verified by operation of the Push-to-Test button.

No. The most common reason for a 2-pole circuit breaker feeding two branch circuits is the use of multi-wire branch circuits, also known as shared neutral wiring. This means that the two branch circuits use the same neutral conductor as a current return path to the loadcenter or panelboard. In these cases, a 2-pole AFCI, such as the Siemens Q215AF, should be used to replace the 2 pole conventional breaker. Two 1-pole AFCIs cannot be used with this wiring method.

If separate neutral wires exist for both branch circuits, then two 1-pole AFCIs can be used. Each branch circuit load conductor and its corresponding neutral conductor must be connected to the same AFCI for proper operation.

Multi-wire branch circuit inspections and repairs should be performed only by qualified electricians.

An AFCI breaker may feel warmer to the touch than a non-AFCI circuit breaker. This is due to the heat generated from the power supply for the electronics. Siemens AFCI breakers tested in an average ambient temperature of 23° C (73° F) operated at an average temperature of 38° C (100° F.) This is well within the UL Standard 489 Section 7.1.4.1.6 which states - Temperature rises on handles, knobs, and other surfaces subject to user contact during normal operation shall not exceed 60°C (140°F) on nonmetallic surfaces.  It is warm enough to detect with the hand, but this heat does not impact the operation of the AFCI.

Siemens AFCI circuit breakers are suitable for use in existing products manufactured by I-T-E, Gould, Siemens-Allis and Siemens Energy & Automation. Specifically the AFCI circuit breaker Types can be used in any of these products in accordance with the following table.

This usage of these AFCI circuit breakers also includes their use in any series ratings marked on the products at the same levels.