Hello everyone,

I'm posting here because I am having (and want to publicly announce) some unacceptable issues with recent dual-function AFCI and GFCI receptacles.  Specifically, I’ve had them either fail prematurely without initial warning, or fail to trip in the presence of a hazardous arc.

Last month, I had a dual-function Eaton receptacle fail without initially giving any warning.  Upon doing a monthly test, the red "failed" LED started flashing, meaning the outlet had already been defective for some time prior.  While I get that the AFCI portion usually doesn’t “self-test,” unlike the GFCI part, the quality control still seems horrid considering it was less than 3 months old.

Fast forward to now, and I replaced the bad Eaton with a dual-function (GFCI/AFCI) Leviton, which is stated to have series arc protection.  Eventually, curiosity got the better of me, so I decided to put the thing to the test.  Please note I know what I’m doing around electricity, so please don’t attempt what I’m about to describe unless you’re experienced! Anyways, I started by hooking a stripped power cord to a kalamata olive (no joke), which is similarly conductive to a pickle.  It quickly started sizzling and making bright, sputtering yellow arcs before blowing smoke.  The AFCI never tripped during all of this!

Thinking the arcing of the olive may have been too low-current, I then tried something more drastic.  I took an extension cord, and cut the neutral conductor.  I plugged in a 1500W space heater, and sparked the severed leads.  It made bright arcs, turned the insulation black, and made bright orange sputters that even caused the copper to bead!  That didn’t work, either.  Finally, I took a piece of mechanical pencil lead with a high graphite content, wrapped one end of the severed extension cord wires around it, and then continually arced it with the load connected.  Although it sustained a sputtering (and continuous) series arc, the attached load still remained powered on and the outlet did not detect this.  Had this happened in an unknowingly-damaged power cord in the middle of the night, I could have woken up to smoke and flames (if I got lucky enough).  Thus, I am seriously questioning if the AFCI is a “gimmick,” especially due to what I’m about to express below.

Investigating further, it turns out I’m not alone in my issue.  An Eaton AFCI breaker, in this video uploaded by a home inspector, failed to trip when an outlet started severely arcing, and almost burned down a house.
See HERE: https://www.youtube.com/watch?v=pHkJ8maQ-mU

So, in summary, I have reason to doubt that AFCIs really do what they are supposed to, and that they may be giving a false sense of security (at least in terms of series arcs).  I’m not sure why it has been so difficult over the years to get them “just right,” and even now, they still seem to be far from perfect.  It appears they’re either too sensitive and trip when you try to use a common appliance like a vacuum, or aren’t sensitive enough to detect hazards.

Seems completely unacceptable to me, considering the manufacturers could cost people their lives and/or homes with this type of issue.  As the consumer, we entrust that when we receive a product with safety markings (e.g., UL), as well as from what we perceive to be a reputable company, we'd get better than this.

That's NUTS !

I know a few licensed electricians.

None of them like AFCI's. They false trip frequently and result in lot's of call-backs.

They are a good idea, but don't work well in the real world.

Seems like they nuisance-trip a lot also.  My reaction has always been "Arc? Aren't somethings supposed to arc?" Ex: fluorescent/HID lights, oil fired boiler transformers, etc. 

My second reaction to arc fault circuit breakers has been "What about when the one for your boiler nuisance-trips at -40*F when nobody is home?"  In places like Fairbanks, Alaska, after about 6-8 hours you have pipes and toilets start breaking...not long at all!

The problem with AFCI selectivity is of a principal nature, its reliability can never be any close to 100%. Their sensitivity setting is always a compromise between the fault detection sensitivity vs nuisance tripping frequency. Either it wont detect weaker signature arcs, or it will trip on e.g. power tools. Just the way how they work can not do much better, the only difference among models could be how that trade of is set.

The AFCI does not respond to the amount of the current, but to the high frequency content (pulse modulated RF) in the current. It relis to the ability of the negative dynamic impedance of an arc to form an RF oscillator with the wiring impedance.
The problem is, not all arcs are fast enough for the negative impedance to be present at the wire resonance frequency and strong enough to overcome the RF losses in the wiring, to really start oscillating or oscillate with high enough amplitude.

The lighting systems are on purpose designed to eliminate all the oscillations, so there is nothing to trigger the AFCI.
The same, if you give the arc a series resistance ballast, it will form RF losses so strong it wont oscilkate either, so such arc becomes undetected.
What makes the oscillations more likely to happen (so the arc detected) are the RF suppression capacitors/filters oninputs of many appliances usually responsible for series arc caused fires (like washers, driers,...; their risk comes mainly from the way how they are used - turned ON and left practically unattended for hours). These filters reflect the RF back, so help to create conditions for the arc to oscillate and so trip the AFCI.

Other problem is the elevated "bacground noise" from all the electronic gadgets. In order to not false trip on these, the AFCI contains a kind of AGC circuit responding to the steady noise by reducing the sensitivity. The consequence is, it needs stronger arc signature to trip, so mainly lower current series arcs wont be able to trip it anymore.


So i  my eyes the use of AFCI can not replace the need to make all the high arc risk points (wire junctions,...) fire safe even when the arc occurs there (breaking the circuit by the arc heat is a valid method, having the junction box open on a dusty area is not). And use the AFCI only as an extra level of protection.

And of course use (and respond to) all the selftest features the protector is equipped with, as tge detection circuit is rather complex so it may fail and thist failure would be reported by the testing procedure. But it has its value only if the user respond to this failure indication and fixes it (so mostly replacing the device, I dont think any maker would allow internal repairs).