Author Topic: AFCI (Arc-Fault) Breakers Ineffective?  (Read 29 times)
MVMH_99
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AFCI (Arc-Fault) Breakers Ineffective? « on: Today at 04:14:50 PM » Author: MVMH_99
Hello everyone,

   I have had some recent experiences with AFCI (Arc-Fault Circuit Interrupter) breakers not functioning as advertised or claimed, and I thus wanted to share this.  I found this both disconcerting and interesting at the same time.  I have two recent experiences, collectively, that I believe highlight a slightly concerning manner in which these breakers may not actually perform as intended when “called upon.”  This post will probably be a little bit long, but I have a good amount of stuff to cover.

   For background, in late 2022, we had most of our house re-wired, and, per code, had AFCI breakers installed on all of the new circuits.  We also used dual-function AFCI/GFCI breakers on the bathroom circuits, although AFCI is still not quite yet required in this location.  We thought it might be nice to have the added protection, not yet knowing just how effective (or not) these AFCI breakers really were.  Just for reference, all of them are Square D Homeline breakers, all manufactured around the same time.  They are also combination-type ones, and not the older branch/feeder type (the earlier version that could only detect parallel arcing).  So, in theory, they are supposed to respond to series arcs.

   My first encounter with the breakers not performing as intended was when my mom’s hair dryer started malfunctioning and arcing inside, presumably due to a loose internal collection.  She reported that there were beautiful blue and green sparks inside (not from the motor itself, but presumably due to a loose connection that had gradually developed), and yet, the dual-function AFCI/GFCI did NOT detect this.

   Most recently, I had a cheap extension cord with an inferior internal contact start arcing with my Chromebook charger.  You could hear it arcing and crackling inside, and the arcing was even strong enough to cause the lights (on a different circuit, mind you) to start flickering slightly!  This, to me, was particularly concerning, as this is EXACTLY the type of fault that these breakers were INTENDED to be able to detect and shut off, and yet, NOTHING happened here!  The breaker just stayed on, and the arcing continued, getting progressively worse.  If no one had been around, this could have turned ugly, needless to say!

   As a result of my experiences above, it is my conclusion that the AFCI breakers do not really function as intended (at least on series arcing), and that they would not prevent an electrical fire were a “true” series arc fault to actually occur.  This is even “backed up” by a video I found a while back, where someone plugged in a toaster oven to a newly-connected AFCI circuit, loosened one of the receptacle screws, and allowed it to freely arc.  Even in this instance, and under a circuit with a much higher load than a small laptop charger, the AFCI still did NOT trip.  I therefore believe that the protection provided by these AFCI breakers, even if somewhat better than a regular circuit breaker, is still inferior compared to how they are advertised and what they were actually intended for.

   In closing, I do believe the theory of the AFCI was good, and that they had great potential.  However, when they were a new product, they were lobbied into code, largely influenced by the manufacturers.  And, even then, they weren’t ready for “prime time,” as they had tons of nuisance tripping problems that caused countless headaches for homeowners and electricians alike.  In addition, perhaps the testing methods used to certify them per UL requirements are not “real-world” enough, based on what I’ve described above.  Either that, or perhaps they just aren’t sensitive enough anymore so as to prevent the major nuisance tripping issues from returning.  In any case, however, I now seriously doubt as to whether or not these breakers would actually prevent a fire from starting, and it seems to me right now like they may be an unjustified expense.

   If anyone has any thoughts or input on this topic, I’d love to hear!
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