I believe AFCIs with GFP have uncovered well over a dozen problems that involve wiring errors, over driven staples, damaged insulation, defective devices, crossed circuits, high impedance faults to ground and yes arc faults to ground. All of which are code violations, shock hazards, create magnetic fields and are fire hazards in themselves one way or another. Thus, a myriad or problems are brought to attention and corrected via GFP that a normal breaker would miss.
So in that regard GFP catches the brunt of the errors produced by sloppy electricians as well as occasional mistakes even the best electricians can make by accident. Further, as long as the GFP remains functional, protection is offered long after construction has finished. Any event involving ground is cleared, signaling a problem.
Thus I would say an AFCI with GFP or just plain GFP is a giant step forward in electrical safety.
The biggest advantage is that GFP alone is not prone to nuisance tripping. Chances are, if it trips, a contingency has occurred in the circuit.
As for the arc logic itself and AFCIs without GFP its up for debate. Arc logic catches only current ripple events, and that detection is only as good as manufacturers can make it. Arc logic will not catch anything that does not involve an arc signature. Those none arc events are: high resistance hot to ground faults; neutral to ground faults; splices submerged or in contact with water; crossed hots or neutrals between circuits; shock/fire hazards such as current leaking onto unintended paths via damaged insulation onto pipes or metal ducts not possessing a low impedance path back to the source. All real world hazards arc logic will not detect. I will even go on a stretch to say that 30ma and below GFP can protect life and property to some degree with a ground fault and open EGC occurring simultaneously.
So with GFP aside we have rare events like series arcs caused by (for example)a loose device terminal; or parallel arcs like a hot to neutral arc fault not involving ground. So arc logic
if perfected could detect an overdriven staple in NM without a ground or where the staple does not involve the EGC. Outside of this I cant think of where a parallel arc fault condition might occur in branch circuit wiring itself.
As for terminals, sustaining a series arc there is difficult, and the biggest revelation comes that nearly all loose connections result in glowing high resistance points, not arc signatures. A glowing connection is something neither AFCI, GFP or standard protection will catch, yet remains Id say the biggest cause of electrical fires.
So with that said both series, parallel and arcs themselves are still something being understood in the role of fire safety or flat out misunderstood.
I also want to point out for those who might be reading this post for the first time with no background that parallel arcs can be detected without an AFCI. That's right, all it takes is lowering the magnetic trip threshold in a breaker. So that overdriven staple not involving ground will be cleared successfully, without an AFCI.
http://paceforensic.com/pdfs/Circuit_Breakers_The_Myth_of_Safety.pdf
Arc fault logic may have a benefit outside the wall with cords involving series arcs, something that GFP or low magnetic trip will not catch. I can see a cord being able to hold a series arc under the right conditions like furniture rocking on it, as well as a parallel arc condition not involving ground.
But, real world evidence of that resulting in fires or frequency of occurrence...?
However in all the above scenarios, we are assuming the logic is perfected and will not nuisance trip. At this point that is not the case. It is definitely not, and will not be with the limited computing power or the still being understood phenomenon of detecting arcs. Its a work in progress.
Series arc faults are rare in hard wiring, and parallel arc faults might be the same but heck low magnetic trip will cover that, while the rest and than some will accurately be detected with GFP at no nuisance trip cost.
In light of all this is arc logic really worth the headache, money and effort? IMO no way.
Rather than try to reinvent what is already perfected, why don't AFCIs proponents and the CMP turn to other first world countries which bear lower fire statics. Because I can promise that you are years behind.
How do they do it? Without AFCIs!
1. First RCDs (GFP) is on nearly all branch circuits. Not at outlets, but originating in the electrical panel. This has been required for over 30 years in most places yet the US and Canada are the only first world countries still acting like its inconceivable.
So right there 100% of arcing ground faults are caught along with other benefits GFP brings. You don't need cotton balls to prove that.
2. Breakers for general use circuits have lower magnetic trip thresholds.
So right there a parallel arc fault will not likely continue unrestrained.
At this point for 30 years other countries have been using pretty much what is a none combination AFCI on all branch circuits without listed appliances tripping them.
3. Testing of circuits and no backstabbed outlets, which also provide another layer of benefit...
But discarding everything stated so far I want to bring forward the biggest cause of electrical fires: glowing connections. If this issue was addressed, only then would we see a real decline in electrical fires.
In 2015 I still see nothing to address them if not encouraging them like backstabbed outlets despite a well respected study done in the 70s on them.
Sorry for the rant, just needed a place to put this. :ashamed1:
I guess one has to ask, has anyone actually seen a real arcing condition?
