|
1 members (Scott35),
380
guests, and
29
robots. |
|
Key:
Admin,
Global Mod,
Mod
|
|
|
|
Joined: Nov 2000
Posts: 2,148
Member
|
Look here for an AFCI discussion that was held at the George Washington Chapter IAEI meeting. This was also published in the chaper news section of the IAEI magazine. Scroll down to the March 19 meeting report. Here is the intro to the report; We were anticipating a less-than-sanguine perspective on the protection provided by circuit breaker AFCIs, supported by a live demonstration. What we got, which kept us talking far longer than many another program, was more than we had expected. The presenter was consultant Bernard Schwartz, P.E., a Fire Protection Engineer formerly of the United States Consumer Product Safety Commission. He was ably assisted, and opposed, by Clive W. Kimblin, Cutler-Hammer's Manager for Applications and Standards. It was not a catfight, but it certainly was lively. Don
Don(resqcapt19)
|
|
|
|
|
Joined: Nov 2000
Posts: 2,236 Likes: 1
OP
Member
|
https://www.electrical-contractor.net/ubb/Forum2/HTML/000352.html This is the thread with Don's insight from the beginning, and the rep from CH. I stayed quiet for most of the thread, but I'm not going to be quiet anymore! ![[Linked Image]](https://www.electrical-contractor.net/ubb/eek.gif)
-Virgil
Residential/Commercial Inspector
5 Star Inspections
Member IAEI
|
|
|
|
|
Joined: Nov 2001
Posts: 280
Member
|
Don: What about series arcs, which AFCIs cannot stop? Both Schwartz and Kimblin agreed that there is no commercially-available technology that hopes to identify them and distinguishes them from legitimate loads. (Schwartz said that, to his knowledge, there is no such technology even in the works.) If there are dangers associated with arcs occurring at wiring terminations on devices or at splices, their characteristics may be indistinguishable from the arcs drawn by thermostats or switches. But Kimblin downplayed their danger, which Schwartz's demonstration might have caused the audience to see as major. He said,"It is essentially impossible to get a series arc by drawing two pieces of copper apart up to100, even 200 amps, past the half-arc [the zero-crossing point]. It will be very difficult for it to start a fire." In Europe, Kimblin noted, with standard utilization voltage of 220 or 240 volts, the risk that a series arc, whose current is limited by the load being fed, will not self-extinguish is greater than it is here. He named UL 1699 as a standard that requires includes protection against possible series arcs in NM-B (but not apparently, other cables such as ACHH, SEC or SER). Any series arc in a conductor that is broken inside its insulation must self-extinguish before a flame can leave the cable sheath. This is his basis for arguing that, in any grounded cable, the 30 mA ground fault protection will interrupt power, thanks to contact between the damaged conductor and the grounding conductor, before a fire can be started. Further, the ground fault interrupting characteristics provide some "glowing connection" protection at receptacles. This is what I have been looking for someone from the industry to say that yes they dont prevent series arcs, and as they say the rest is history. Steve: I did check out AFCI on the search engine and all I got back was GmBH, Gesellshaft mit Beschrankter Haftung, and something about limited liability. But seriously though, you say blindly accept Mark (et all)...ask, & do not blindly accept ..... facts please..
(the archives will concere) But what do we do when we buy a panelboard we are accepting the UL label the companys word that there stuff is not junk, ie Siemens, Squar-D , and even Cutler-Hammer, so now what Sq-D breakers(QO for quick-open) are supposed to open in 1/60 of a second believe it or not. Now back to the AFCIs I have seen more receptacles burnt on the line side,ie the hot than a complete failure across the entire receptacle, due to those back-wired receptacles. You are right if they dont prevent that then what good are they and for that matter what good is all the testing and as you say 'Not-so truthful' advertising, but here we are 2002 new code come out and we are mandated to install them in all new construction, at least we are here in Hicks-ville Ohio, What do I tell the customer? Well we have to install these beauties, but there is no guarantee they will work as they should, 'Really I can see the customers flocking to me to put them in there homes', To Sparky66: You are Right. So now that I see the light who do we believe, they are selling a pig in a poak. Don dug that article out of a meeting of the IAEI, in Washington, The minutes of which were published on there website, but nothing made to public knowledge.\ I always said I was never too old to learn something new, and sometimes not always happy with the new knowledge. -Mark
|
|
|
|
|
Joined: Nov 2001
Posts: 280
Member
|
Series arcing is caused by a loose connection in series with the load circuit. Series arc current is limited to a moderate value by the resistance of the device that is connected to the circuit, such as an appliance or lighting system. The amount of energy in the sparks from series arcing is less than in the case of parallel arcing but only a few amps are enough to be a fire hazard. Series arcing is particularly insidious because the arc current remains well below the rating of the thermal breaker and the magnetic sensor will never respond to such low amplitude currents. Since the peak current is never greater than the steady-state load current, series arcing is much more difficult to detect than parallel arcing.
Hazardous Conditions
Loose wiring connections at outlets or switches.
Loose wires twisted together and held by a wirenut.
Frayed cords on appliances.
The detection of series arcing is complicated by natural occurences of arcing when switches are activated or appliances are plugged into the socket with the power turned on. These short-term arcing situations are generally not hazardous and should not cause nuisance tripping.
Non-Hazardous Conditions
Toggling a power switch.
Plugging in an appliance.
Replacing a light bulb.
Impending failure of a light bulb.
Switching of a motor relay.
When the normal load current being supplied by the circuit is below the breaker rating, circuit breakers in common use today do not react to an intermittent condition. For example, if a hair dryer normally draws 10 amps but the wall outlet has a loose screw terminal so it makes contact only half the time, the average current is 5 amps and the thermal circuit breaker thinks the current is still well below its rating of 15 or 20 amps. In this case the magnitude of the arc current is limited by the heating element in the hair dryer and the maximum value is never more than 10 amps.
New arc fault circuit interrupters (AFCI's) have the ability to detect the distinctive difference between normal current and intermittent arc current. In 1994 an insurance company survey of 660 fires of electrical origin indicated that more than one-third of them were due to arcing conditions. By opening the circuit when a hazardous condition is sensed, electrical safety can be significantly increased. AFCI's in compact and economical packages have been made possible by advances in integrated electronic components.
Home Waveforms Breaker Testing File Format Contact Zlan ------ Well here it is Series Arcing is not considered a very big hazard. And that agrees with the IAEI meeting- -Mark
|
|
|
|
|
Joined: Oct 2000
Posts: 5,392
Member
|
Don, thanks for posting The minutes of the "George Washington Chapter IAEI" per Dave Shapiro. I had lost that and spent time searching to post it here, I found it most revealing and recommend it as reading . The 'heavies' involved debate just about every AFCI concern voiced on the BB's GmBH, Gesellshaft mit Beschrankter Haftung Mark, i meant this forums search engine, we've pretty much gone the distance here on this in relation to most forums. as to breakers, even UL has been had in the past.......
|
|
|
|
|
Joined: Jun 2001
Posts: 642
Member
|
I am glad that my home state of Nebraska chose not to be involved with the manufacturer's beta test of thier latest snake oil AFCIs. Yes i lobbied some board members-but it did not take much discussion. Most did not believe the sales lines from the reps. Lacking real accutate and reliable test data, and lacking any actual real world experience showing actual reduction in fires, makes the B/S sales pitches suspect. As I said in an older post if the product is that good they would not have tried to cram it down our throats.
My company still will NOT warrent them and if possible will not install them.
Also Nebraska did not adopt the greater than 3 floor change for romex.
ed
|
|
|
|
|
Joined: Nov 2001
Posts: 280
Member
|
To all : After all our discussion and debate on this subject I wrote to ZLAN and received this reply: Mark,
We have lab test equipment that can verify both GFCI & AFCI functions.
A year ago we sampled all manufactures of AFCI breakers. We were shock to
find that none provided any series arc protection (Arcing that occurs below
the handle rating). On the other hand we could not believe the
specifications that U/L was pushing for series arcing. You would have really
hated the breaker if they had fully implemented U/L's 1699.
Between U/L & NEMA, I am not sure we will ever have a functioning AFCI. The
technology was available 10 years ago.
I believe Congress will have to step in to resolve this issue.
Check with your Congressman.
Regards,
george@281.com
lee@zlan.com There solution is to have Congress step in and solve the problem, what ever happened to good old American know-how, suck-it up and get the job done. I cannot believe what this guy is saying, there is no-way they can do the job without someone elses help. I apologise for my belief that there is still some honor out there, you know truth in advertising, obviously I am about 30 years behind the times. If a job cant be done we give it to congress to do, yeah they will assign a committee to and we wont hear about it for another 30 years. Totally disgusted -mark-
|
|
|
|
|
Joined: Aug 2001
Posts: 7,520
Member
|
Mark, Doesn't that just go hand-in-hand with the liability issue? It's always somebody else's fault. It's always somebody else's reponsibility to see that something is done. Just give me the big bucks, and pass the buck to somebody else. ![[Linked Image]](https://www.electrical-contractor.net/ubb/frown.gif)
|
|
|
|
|
Joined: Apr 2002
Posts: 2,527
Moderator
|
paul-- Yes, and in the US, leave it to the even fatter lawyers to duke it out.
|
|
|
|
|
Joined: Oct 2000
Posts: 5,392
Member
|
quite the letter Mark. It would seem our trade needs some watchdogs if Zlan would ask for Congressional intervention.. or rather, the watchdogs need watchdogs.....
|
|
|
|
Posts: 47
Joined: March 2008
|
|
|
|
