Arc Fault Circuit Interrupter (AFCI) Nuisance Tripping:

Nuisance tripping of an electrical safety device such as an AFCI refers to annoying and un-necessary shut-downs of an elecrical circuit, device, or appliance that was unnecessary and/or did not represent a condition for which the device was designed and intended to operate.

Nuisance tripping of AFCIs may be a more-serious problem than it first appears, as annoying and pereceived-incorrect or unnecessary operation of any safety device may lead a consumer or building occupant or even a licensed electrician to subvert or even remove the device, thus leaving real safety hazards un-protected.

This article series about AFCIs combines electrical code information, studies & reports of AFCI performance, field experience with AFCIs, and information from the U.S. CPSC on AFCIs with additional details and commentary answers most home owner and home inspector questions about installing, testing, and inspecting AFCIs - arc fault protectors in homes.

Electrical Arc Fault AFCI Nuisance Tipping or Crosstalk Problems

This material was originally prepared by DF for the American Society of Home Inspectors New England Chapter,( ASHI -NE) Educational Seminar, Sept 22-23, 2008.

Portions of this text are quoted from the Arc Fault Circuit Interrupter (AFCI) FACT SHEET provided by the US CPSC .

Coffee Maker Demonstrates Early warning about nuisance tripping of AFCI circuit breakers and consumer objections to these devices

AFCIs devices are tested under the UL 1436 standard, and are required to have included in the instructions the following clause (or equivalent):

"CAUTION: AFCIs recognize characteristics unique to arcing, and AFCI indicators produce characteristics that mimic some forms of arcing.

Because of this the indicator may give a false indication that the AFCI is not functioning properly. If this occurs, recheck the operation of the AFCI using the test and reset buttons. The AFCI button test function will demonstrate proper operation."

Watch out: we have heard several reports of excessive "nuisance" tripping of arc fault circuit interrupters, and our own limited testing has confirmed this problem in our laboratory where we installed the coffee maker shown at left.

On a newly-wired AFCI electrical circuit with tight, well-made connections and powering a string of electrical receptacles, we connected a single device: a Keurig™ coffee maker to the circuit (photo at left). The circuit also supports a wall mounted light that uses florescent bulbs. No other devices were connected to the circuit.

The coffee maker was set to turn itself off automatically after one hour of idle time. Yet consistently over 30 days of testing, every day we observed that the 15-A Square D AFCI for this circuit tripped off at least once.

We suspect that electrical properties of the coffee maker may have been the source of noise on the circuit that was causing the AFCI to switch off. Replacing the AFCI with a conventional 15-A Square D circuit breaker completely eliminated the nuisance tripping on this circuit.

Three other AFCIs were installed in the same electrical panel, but only one was connected to an electrical circuit in active use. On that circuit, also supporting a string of electrical receptacles powering lighting and computer equipment during the same 30-day test period, no nuisance trips of the circuit were observed.

Photo: a view of the interior components and the three wiring connection points of an AFCI circuit breaker, courtesy Dr. Jess Aronstein.

[Click to enlarge any image]

Watch out: do not attempt to disassemble an AFCI nor any other circuit breaker. Disassembly is not required for making proper electrical connections, and doing so is likely to make the circuit breaker unsafe or unreliable.

Watch out: as with GFCI's discussed

at MULTI-WIRE CIRCUITS,

installing AFCIs on multi-wire branch circuits using a shared neutral requires installation of a common trip tie, and nevertheless the circuit and this circuit protection device may be subject to further nuisance trips or unexpected behaviors.

Watch out: An installing electrician informed us that many of his customers were complaining about nuisance tripping and that he was asked by those clients to remove the AFCI devices and to replace them with conventional circuit breakers. This raises an issue about national and local electrical code compliance and about building electrical and fire safety - removing a code-required safety device.

Further testing of the nuisance-tripping AFCIs as well as three others installed in the same electrical panel and samples of non AFCI breakers of the same age, rating, and brand is underway and will be reported here.

Also see APPLIANCE DIAGNOSIS & REPAIR

Nuisance tripping refers to a circuit breaker or an AFCI that trips off, turning off electrical power when there was no apparent reason to do so.

In the photo I'm holding an AFCI-type circuit breaker after un-snapping it from its position in a Square-D electrical panel. I had to remove this breaker because of nuisance tripping.

Some sources assert that what appears to be "nuisance tripping" of AFCI's actually occurs due to wiring practices of some electricians more than for any other reason. These include

• Reversed hot and neutral wires - reversed polarity - which is an unsafe condition
• Shared neutral wiring on single pole circuit breaker circuits: this is already an existing problem with GFCI's on multiwire branch circuits.
• Incorrect or accidental connections between the ground and neutral wire: this is also an unsafe condition which can permit live current to flow on a ground wire that should normally never carry current. We've personally seen this condition lead to an electric shock.
  
  A common source of accidental ground-neutral connections occurs when an electrician over-tightens the clamp connector on BX (armored cable) where it connects to a steel junction box. Our ex-brother-in-law made this mistake at every single BX connector when he did his own over-zealous wiring in a New York City apartment.
  
  When he installed a GFCI circuit breaker to protect some circuits, he could not keep the breaker from tripping immediately whenever power was turned on.
  
  We saw that his over-tightening the connector pinched inwards the edges of the BX cable. If the BX cable edge cuts into the hot wire the electrician (or Matthew) discovers this fault immediately when power is restored to the circuit.
  
  But if the cable edge cuts into the neutral wire, the electrician (or our brother in law) does not discover this fault until a GFCI or an AFCI is installed on the circuit, or until someone touches a supposedly safe armored cable wire exterior and gets a shock.
• Normal arcing in appliances: Nuisance tripping that could occur from the normal arcing that occurs in some appliances (such as a vacuum cleaner motor) has been considered in the design of the AFCI circuit. The AFCI is designed to tell the difference between this ordinary arcing and the type of arcing in a circuit that may cause a fire.

The experts also use the term "crosstalk" in discussing nuisance tripping on AFCI circuits. Our first citation (Engel 2012) is discussed in more detail in the article above where readers will also find a link to the full-text of the article. The other citations are examples of research papers discussing crosstalk and nuisance tripping in AFCI breakers.

• Engel, Joseph C. "Combination AFCIs: What they will and will not do." In 2012 IEEE IAS Electrical Safety Workshop, pp. 1-18. IEEE, 2012.
  Abstract:
  
  All new home branch circuits are required by Code to be electronically protected, either by Ground Fault Circuit Interrupters (GFCIs) or Arc Fault Circuit Interrupters (AFCIs). Areas including kitchens, bathrooms, garages, etc. must be protected by GFCIs, while living areas must be protected by AFCIs.
  
  The AFCI is the fourth generation in residential branch circuit protection after fuses, circuit breakers, and GFCIs. National Electrical Code in 2002 first added AFCI protection, for bedrooms outlets.
  
  In 2008, coverage was expanded to all living areas, also adding that only “Combination AFCIs” are allowed. Manufacturers and UL claim that arcing across a break in a cord's conductor is hazardous, and that a Combination AFCI will respond to prevent a fire.
  
  The author believes the claim is unproven, and will explain why the disallowed Branch/feeder AFCI provides more protection at less cost.
• Restrepo, Carlos E. "Arc fault detection and discrimination methods." In Electrical Contacts-2007 Proceedings of the 53rd IEEE Holm Conference on Electrical Contacts, pp. 115-122. IEEE, 2007.
• Johnson, Jay, and Jack Kang. "Arc-fault detector algorithm evaluation method utilizing prerecorded arcing signatures." In Photovoltaic Specialists Conference (PVSC), 2012 38th IEEE, pp. 001378-001382. IEEE, 2012.
• Johnson, Jay, and Jack Kang. "Arc-fault detector algorithm evaluation method utilizing prerecorded arcing signatures." In Photovoltaic Specialists Conference (PVSC), 2012 38th IEEE, pp. 001378-001382. IEEE, 2012.
• Ming, Zong, Yang Tian, and Fengge Zhang. "Design of arc fault detection system based on CAN bus." In Applied Superconductivity and Electromagnetic Devices, 2009. ASEMD 2009. International Conference on, pp. 308-311. IEEE, 2009.

How to Report an AFCI or other Electrical or Product Failures or Incidents to the U.S. CPSC

Please use the CPSC form found at https://www.saferproducts.gov/IncidentReporting

To comment on or suggest additions to this article use the Comments Box found below, or use our email found at CONTACT

 

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Reader Q&A - also see RECOMMENDED ARTICLES & FAQs

Question: AFCI vs grandfathering homes older than 2008

This does not address grandfathering for homes older than 2008! - John, 7/24/2011

Reply:

Granfathering and the AFCI requirement: good point, John. We find a variety of opinions among building code officials. At a recent building addition project the BCO wanted AFCIs in the new sub panel in keeping with the new electrical code AFCI recommendations, but he also decided that other areas in the home needed certain updates too.

Other electrical inspectors and building code inspectors look only at the new work - I'd say that's the most common case. Only when an older home is being renovated to include electrical work will most inspectors call for current codes to be complied-with.

A more subtle exception occurs in the case of egregious electrical hazards: when an older home is being purchased, some lenders and some insurance companies may require certain updates such as in panel ampacity or in replacement of some of the more troublesome brands (FPE Stab-Lok is an example.)

Question: are AFCI's required on lighting-only circuits?

do you have to use arc fault on lighting only circuits? - Hugh Owen 8/22/2011

Reply:

Yes. On the illustrations I've seen the overhead lighting circuits were included. see 210.12(B) Dwelling Units - quoting the Minnesota Electrical Association reference found at the bottom of this article:

Combination-type AFCI-protective devices are now required in all dwelling unit rooms, except for kitchens, bathroom, garages, basements, and rooms or areas not specified in this section. This continues the incremental migration to provide whole-house AFCI protection for dwelling units that was the objective of the original proposals in the 1999 NEC development cycle.

This section was revised to include a list of rooms and areas where the serving branch circuits are to be protected by arc-fault circuit-interrupter protection. Essentially, the requirements for this protection are expanded to most areas and rooms in the dwelling unit with the exception of those named above and other areas or rooms not specifically identified in this section. The AFCI-protective devices must be listed combination types.

Question:

I don't have space in the panel to make proper ground bus connections. - Roger 9/11/11

Reply:

Roger, as long as your panel won't be overcrowded, you can always add an additional ground bar (or neutral bar) in the existing panel, connecting it to the originals and locating it where your AFCI white wire will reach.

Question:

I have a Sylvania main breaker panel in an existing dwelling. I am adding 3 circuits to basement finish.
Inspector wants a Listed product for the panel . Any idea what AFCI breaker I can use? - Nice Article 12/10/11

Reply:

Nice:

Any AFCI breaker sold at any electrical supplier will be code compliant. Just how well the product works is a different issue as discussed in this article. Be sure to see the comments and links to Dr. Engel's paper given in FAQs. below.

Question: having trouble wiring 14-3 wired homes

How to deal with 14-3 wired rooms. I need AFCI for the outlets and the lighting, I have wired 14-3 and would need a special AFCI that doesn't seem to be offered by Square D. - Eric J 5/22/2012

Reply:

Erick J

You raise an important question: how to use AFCIs or GFCI's on 3-wire circuits. I don't know a solution and so far the solution certainly is not offered in the device itself. We have ongoing reports as well as direct experience with nuisance tripping and so unreliable behavior when AFCIs or GFCI's are installed on shared-neutral circuits.

The electrician I worked with most recently says he's changed is policy and won't install 3-wire shared neutral circuits where an AFCI or GFCI is going to be required.

In sum, AFCI's are NOT going to work properly on shared-neutral electrical circuits; neither do GFCIs.

Question: Nuisance Tripping of AFCI devices on circuit used to power a TV

I have two Seimen's AFCIs for 3 bedrooms. They were placed approx spring 2004 in a new build. No problems until several months ago with LED TV in master bedroom. Breaker would trip upon trying to turn on tv on rare occasion. At first seemed overload but now it trips every time TV is turned on.

TV is tripping the other AFCI in the other bedrooms as well. It IS NOT tripping the standard breakers elsewhere in the house. Are these older model AFCIs needing replaced to handle the load of the new appliances? Have new breakers become more reliable as stated above at avoiding nuisance tripping (which I assume this is)? - Kathy 8/20/2012

Reply: how to report AFCI problems to the US CPSC:

You are reporting nuisance tripping.

You should also contact the US CPSC directly to make your concerns known.

Use this US CPSC Incident Report Form to report Zinsco or Sylvania-Zinsco equipment failures and problems. Please also report incidents to this web author.

Question: nuisance tripping of AFCI circuit with ham radio equipment.

i have ham radio equipment
the AFCI is reading the fluctuating current demands as arching. breaker constantly trips. this is a pain! can i safely replace the afci with a standard breaker? - Paul 8/23/2013

Reply:

Paul this sounds like another instance of nuisance tripping. You can replace the AFCI with a standard breaker and stop the tripping problem; you will be giving up what limited added safety protection the AFCI offered, and you could face a technical issue with your local electrical inspector.

You should also contact the US CPSC directly to make your concerns known.

Use this US CPSC Incident Report Form to report Zinsco or Sylvania-Zinsco equipment failures and problems.

Please also report incidents to this web author.

Questions/comments: on AFCI's: Reference to Engel (2012)

DanJoeFriedman (mod) said:

Repeating Steve's suggestion 1/31/13 that we read Joe Engel's paper on Combination AFCIs, we contacted Mr. Engel as well, and appreciate your contribution of a publicly-available copy of this important paper. In the article above we include a reference and link to

Joseph C. Engel, PhD., IEEE, "Combination AFCIs" What they Will and Will Not Do", IEEE, 2012

Question/comment:

(Sept 2, 2011) Honest Electrician said:

How much money has been paid to the NFPA to make AFCI breakers code since there have been arc outs and fires on protected circuits and they were introduced as code before they were available

Questions: AFCI be used to protect Alum branch wire circuits

(Sept 19, 2014) Mike said:

Can a AFCI be used to protect Alum branch wire circuits

Reply:

Yes, and no.

yes if the AFCI is connected using CPSC-recommended methods (AMP TYCO COPALUM or the King Innovations AlumiConn) to connect the device to the circuit

No if you are thinking of direct-wiring the device to the aluminum wire. I have personally seen an aluminum wired test circuit overheat and begin to burn (we turned off power at that point) while powered through an AFCI.

...

Continue reading  at HOW TO INSTALL & TEST AFCIs or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

Recommended Articles

• AFCIs ARC FAULT CIRCUIT INTERRUPTERS - home
• AFCI GFCI WIRING, TESTING & SAFETY
• GFCI DEVICE SELECTION & WIRING - additional discussion of nuisance tripping & solution by pigtailing
• GFCI PROTECTION, GFCI CODES
• NUISANCE TRIPPING of AFCIs
• HOW TO INSTALL & TEST AFCIs
• SQUARE-D & FEDERAL PIONEER (STAB-LOK FPE DESIGN) AFCI NOTICES [PDF]

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