ECN Forum Forums Code Related Discussion NEC & other Code issues AFCI

Brendan,
I can see why they would want it to be AFCI protected. However shouldn't it be protected on a independant afci breaker? Like Sparky's scenario suggests, if there is a fault in the bedroom and the power is interupted and the batteries are not maintained. (As usual) Would that not pose more of a danger?

James

I am not a code expert, but my preference for my home would be to put the smokes on a lighting circuit. That way, if the breaker saw a arc and responded, it would be evident due to lack of power to the lights.

Sparky, the series arc issue that you raise is a dead horse. I will address this once again:
a.) Series arcs are not dangerous, and occur every time you flip a light switch. You certainly wouldn't want breakers to trip when you turn off a switch.
b.) Series arcs are self announcing. The same thing that happens when you open a switch happens when you open one conductor...voila...no current...no light.
c.) High resistance series faults are dangerous. There is no increased current, so there is no way to detect a change in current flow. However, the heating effect of the resistance will eventually cause a parallel arc or ground fault, both of which are detected by the AFCI, but not by a standard breaker or fuse. High resistance series faults are caused by: aluminum wire, glowing contacts, glowing wire nuts, back-wired push-in receptacle connections, shared neutrals, hot plugs, broken conductors beyond the receptacle, overheated cords and overheated cord-plug connections. AFCI's will respond to ALL of these issues. Standard thermal-magnetic devices will not.

Homes have changed substantially since the circuit breaker was invented back in the 20's or 30's. It is not unusual today to have 10x the number of electrical connections that there were in the 50's and 60's. The technology available today vis-a-vis the AFCI is a substantial improvement over the 70 year-old technology of the standard thermal magnetic breaker.

Recently we had NFPA do some research on the number of fires where electrical arc was the cause of ignition. This is the best available fire data in the US today. Between 1994 and 1998, the annual average number of residential fires caused by electrical arcing is 60,900, causing 490 deaths, and over $900 million in direct property damage.

The question is: do you want to protect the wires in your 2002 home with 1930's technology, or do you want to move your protection into the electronic age?

Breden,
It appears that in the vast majority of cases, the GFP in the AFCI is what actually clears the fault. Why can't we just use the GFCIs for this? The only place that I can think of, in a code compliant installation, where the AFCI would actually detect the arcing fault without a ground fault would be on a 2 wire cord beyond the outlet. According to all of the fire statistics used to get the AFCI requirement into the code, few fires originate beyond the outlet.
Don

Brendan.
Righto….you’re a manufacturer's rep right?
Know that I reserve the privilege of flogging the dead equestrian with my professional counterparts wherever cyberspace will have me & rest assured the fall ROP's will fuel this far and beyond my rants, so i hope you can hang 'til the 05'
The AFCI (Arc-Fault-Circuit-Interrupter) has been a manufacturing coup for the NEC. They are pedaled under shady pretenses in that they allude to the mitigation of ALL arc-faults, the package says "ARC-Fault", the homeowner/consumer will assume expectations from this. They will also expect a performance from the end-sales contact which will usually be us, the Electrical Contractor. Would you feel comfortable if the onus was on you here, I see no gaurantee from CH or other maker, as you have all convienently isolated yourself(s). As a matter of discussion, how many contractors here have sold AFCI's under this assumption? Your assertion that all series arc's of dangerous caliber will simply ground out aids & abets this misleading definition, and quite frankly is an insult to any sparky worth his/her salt. The {glowing contacts, glowing wire nuts, back-wired push-in receptacle connections, shared neutrals, hot plugs, broken conductors beyond the receptacle, overheated cords and overheated cord-plug connections} are not going to all decide to go to ground before dialing 911…..
Further, how will all the AFCI's that I have installed in my service upgrades with K&T fare?
I have questioned Dave Dini of UL , who also sits on the CMP re; 210.12, who's politically correct answer was 'less efficient'. The same goes, I believe , for anything beyond the device due to lack of a third conductor, and I suggest you check your listing(s) for verification, however misworded.
To further compound this is to introduce a sensitive device, admitedly not meggable, into proximal X-former AIC, swells, sags, and all manner of 'lectrical havoc.
Thus the major fallacy…show me an AFCI with one wire to it, or a moneyback gaurantee and I'll change my tune here., otherwise it is a GFPE's cousin
210.12 would do better to be defined as an LCDI, as in 440.65


The other issue is stat's. as a former FF, the forensics' for precise diagnostics may exist, but are rarely called for, and I was never privy to such fanfare in my tenure. Insurance co's do not care, they simply pay off…and the stat's follow suit.....