Combination Arc-Fault Circuit-Breaker VS. Dual Function: Arc-Fault/GFCI Circuit-Breaker

By: Wes Gubitz | Feb 05, 2019

A “COMBINATION” Arc-Fault Circuit Breaker is NOT equivalent to a “DUAL-FUNCTION” Circuit Breaker.

With ever changing electrical Code requirements, a circuit breaker with the ability to provide both Arc-Fault protection as well as Ground Fault (GFCI) protection was long overdue. But beware, the “combination” function that is identified on recently manufactured AFCI circuit breakers DOES NOT provide this AFCI/GFCI protection.

COMBINATION AFCI Circuit-Breaker: Provides protection against both parallel arcing conditions (which is a hot to ground arcing condition), and series arcing conditions (which is arcing that occurs along a single conductor where a portion of that conductor is broken, frayed, or otherwise partially disassembled, causing the current to leap an air-gap to continue on its path).

DUAL-FUNCTION AFCI/GFCI Circuit-Breaker: Combines both AFCI and GFCI branch-circuit protection into one OCPD.

The Combination Type Arc-Fault Circuit Interrupter

Branch circuit protection has steadily evolved over the decades concerning electrical safety for Family Dwelling Units. The Fuse being one of the first advances, then the circuit breaker, the GFCI, and most recently the AFCI. All of these devices are, by action, circuit interrupters; they de-energize the circuit being protected. The fuse interrupts the circuit when there is an overcurrent condition (short circuit or overload), but unlike the other devices, it is a one and done; when a fuse interrupts a circuit, when it blows, it must be replaced. The circuit breaker is also a circuit interrupter. It opens when there is an overcurrent condition in the branch circuit it protects, and it is resettable. Both the fuse and the circuit breaker are designed to protect the circuit against short circuit current and overloads.

The GFCI, the ground-fault circuit interrupter, and the AFCI, the arc-fault circuit interrupter, are devices designed to meet specific electrical safety issues. The GFCI is designed to protect personnel against electrocution while operating tools or equipment on a GFCI protected circuit. It is designed to interrupt and de-energize the circuit if there is an imbalance in current of 6 mA or greater between the line conductors (NEC 100IN). The GFCI is resettable. The AFCI is resettable and designed to interrupt and de-energize a circuit to protect life and property should anomalies that mimic arcing faults occur in an AFCI protected circuit.

Arc-fault circuit protection was first introduced as a requirement for bedrooms in the 1999 NEC that was to take effect in the 2002 NEC cycle. The Code requiring Arc-Fault Circuit-Interrupter Protection, 210.12, has evolved with the technology. The AFCI shall be installed in a readily accessible location, and protect all 120-volt, single phase, 15- and 20-ampere branch circuits supplying outlets or devices installed in dwelling unit kitchens, family rooms, dining rooms, living rooms, parlors, libraries, dens, bedrooms, sunrooms, recreation rooms, closets, hallways, laundry areas, or similar rooms or areas shall be protected…, 210.12(A).

Several Code cycles through and including the 2017 NEC have amended the ACFI requirements such that the rooms or areas shall be protected by any of the means described in 210.12(A)(1) through (6). The means described in (A)(1) is a listed combination-type arc-fault circuit interrupter, installed to provide protection of the entire branch circuit.

According to Siemens, a supplier of combination-type arc-fault interrupter circuit breakers, “Combination Type Arc Fault Circuit Interrupters (AFCI) detects arcing faults (an unintentional arcing condition in a circuit) that standard circuit breakers are unable to detect. The device is intended to mitigate the effects of arcing faults by functioning to de-energize the circuit when an arc-fault is detected. A Combination Type AFCI detects all three types of arcing: line-to-neutral, line-to-ground, and series arcing.”

The most probable and convenient “means” to meet the AFCI Protection requirement for new construction dwelling units is through use of a Combination Type AFCI Breaker, 210.12(A)(1). This will allow the use of GFCI receptacles for those circuits where GFCI protection is required. Another possible and the next probable device to be used in new construction that would also meet the AFCI Protection requirements of 210.12(A) is the Combination Type ACFCI Breaker that also has GFCI Protection, a Dual-Function AFCI/GFCI Breaker. The remaining means described in 210.12(A)(2) through (6) requires a thorough understanding of the related Code and specific input at the local level from the Authority Having Jurisdiction.

What about when an existing circuit that is required to be AFCI Protected has to be repaired or modified?

The Code covers this in 210.12(D)(1) and (2), Branch-Circuit Extensions or Modifications – Dwelling Units and Dormitory Units. In any of the areas specified in 210.12(A) or (B), where branch-circuit wiring is modified, replaced, or extended, the branch-circuit shall be protected by one of the following:

(1) A listed combination type AFCI located at the origin of the branch-circuit

(2) A listed outlet branch-circuit-type AFCI located at the first receptacle outlet of the existing branch circuit.

The electrician could replace the standard circuit breaker with the Combination Type AFCI Breaker to provide the required AFCI Protection, but…. this may not be the best option on older homes. Circuit neutrals must remain separated for AFCI devices to operate correctly. Neutral maintenance is required on new construction, meaning that all neutrals are separated when leaving the panel and do not tie in with any other neutral outside the panel. The Combination Type AFCI Outlet Receptacle may be the better choice when existing branch circuit wiring is modified, replaced, or extended. Check out our electrical license exam prep courses now.

 

10 thoughts on “Combination Arc-Fault Circuit-Breaker VS. Dual Function: Arc-Fault/GFCI Circuit-Breaker

  1. I firmly support a requirement that all circuits in a new home construction should be dual function. The statistics on death by short circuit or arc fault are overwhelming and a few dollars more to save innocent lives especially thru fire is a minimal amount to incur. This could be you or one of your family members.
    Figure an additional 500.00 and make your home safe as best we now how right now.

  2. Well, Jim, that would be swell if the things actually worked correctly. But with the thousands of documented cases of nuisance tripping caused by the AFCI’s inability to differentiate between an actual arc fault and the normal arcing of motor brushes, perhaps it’s an idea whose time has not quite come yet. Alas, the NEC is forcing it on us, nevertheless.

  3. Ditto on David’s comment.
    Jim… you speak like a true investor…
    I doubt anyone can find much fault in the GFCI, but the AFCI posses it’s own saftey hazards.
    Words like fire and electrocution always get tossed in first… but the plans never talk about the thousands
    of home owners tripping AFCI’s unplugginf a phone, vacuuming, turning on an iron.. Now they’re in the dark?
    Now thy’re in the panel… resetting a possible bad issue.. multiple times …
    I a not talking about inconvenience nor cost issues.. This is about a National Mandate on a product that is flawed.
    True prove my point, lets fix the real issues about arching, or overloading. STOP with the waggles or stab in versus the wire nut. twist it and cap it or wrap it around a screw. #14 cu is a joke stick to #12 minimum.
    Arguably the same cost increase as a home full of AFCI’s but now there is an actual inherent value added (material wise and workmanship). Someone is getting rich on these ideas on paper but in the field?
    Let us know Jim, the countless number of lives saved that the industry has dreamed up.

  4. AFCI/GFCI breakers are Flawed in design and need to be Re-designed So they don’t trip just Because a fan picks of speed in a computer. I replaced two of them and it still would trip. went back to a normal 15 amp breaker and no issues.. I would like to add that the AFCI/GFCI 15 amp circuit was not even to half Capacity when it would trip. Just a gaming computer and a monitor and a led light bulb lighting room.

  5. AFCI/GFCI is a Very Flawed design. It trips off the circuit just by computer fan running high. I had a 15 amp GFCI /AFCI on my computer room circuit and it would trip when my fans would pick up RPM ‘s . The 15 amp circuit was nowhere its 15amp limit. Just a computer a monitor and a led room light. Replace with a standard 15amp breaker and issue was fix. Hopefully they re design and flawed AFCI breakers

  6. I recently purchased a new home and the builder stated that he as installed dual function ARC/GFI’s in the panel. Do I still NEED GFCI’s in the kitchen and bathrooms?

  7. I’d like to replace a 20amp single pole AFCI/GFCI which feeds 4 kitchen counter outlets solely with a 20 amp single pole GFCI breaker due to new coffee maker tripping issue. I’ve checked and tightened all 4 outlets for any loose wire conditions without improved success. My home is 1&1/2 yrs old. I don’t know what else to do. Any other suggestions? try a different AFCI/GFCI breaker?

  8. Get a different coffee maker. New codes require AFCI/GFCI. Electrical contractors are bound by the code. Plug coffee pot into different kitchen counter AFCI/GFCI circuit. If this circuit trips too, it’s the coffee maker.

    Had same problem with new mini refrigerator. Customer had to replace.

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