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Joined: Oct 2000
Posts: 2,723 Likes: 1
Broom Pusher and Member
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I have witnessed a Series Arc bridge a gap, which grew up to an Inch or more - in a very hot environment, with minimally conductive surrounding Air, and a potential of 230 VAC (measured after the event).
The bottom Element of an Electric Oven failed while in use, resulting in a Series Arc between the severed ends of the once continuous Heating Element.
When the Element failed, the established Arc could be faintly heard. My Mother and I were standing near the Oven at the time, and did not think too much about the sound - as it was similar to "Bubbling".
After about 15 - 20 Seconds, the sound became less "Bubble-Like" and more "Flame-Like", and the Oven Door was opened.
So Mom opened the Oven Door, only to be presented with a Fat Arc at the bottom Element (scared the heck out of her!!!).
Like the clown I am, I watched the Arc for a few seconds before turning off the Oven (via the Temperature knob).
That was impressive!!! Never thought such a large Plasma would be sustained across a Resistance Element, at a Potential of 230 VAC!
Element was (AFAIK) 4500 Watts, so there would have been at least 19.57 Amps flowing through the Element at the time of failure.
Arc was across the Element only. No L-G Arcing was evident.
-- Scott
Scott " 35 " Thompson
Just Say NO To Green Eggs And Ham!
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Joined: Oct 2000
Posts: 5,392
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As an EC i have no choice but to install what may be up to 30 afci's in a 40 circuit new house wire job here
this amounts to asking for an additional $1K
for a device(s) that provide nothing more than false security
that doesn't make me feel too good
what we can do is simply get the word out to the powers that be
if they care about our trade, they'll investigate this issue, and hopefully come to an amicable conclusion
~S~
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Joined: Jan 2005
Posts: 354
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One concern I do have with such a widespread requirement for AFCI is building up so much heat in the panel, due to packing so many continuously operating (heat emitting) devices in a confined space. Are we going to be seeing 84 slot panel used for 42 circuits?
And what is the long term reliability of AFCI? We haven't seen them in long term (and in all that heat), yet.
I think I would rather see AFCI outlet devices, since at least for residences, cords for utilization equipment may be the greatest risk (not that a nail driven into an NM isn't a risk).
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Joined: Jul 2004
Posts: 9,928 Likes: 34
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I asked this question a few times and I was always assured it wasn't a problem but not really convinced.
Another thing to chew on is the 40c rating on circuit breakers. In a sunshine state garage (where panels seem to be located these days) 40c is not that far from ambient air and inside the panel it could get quite a bit higher.
That will change the trip curve.
I also agree the electronics in these breakers will not like the heat.
It would be interesting to put a temperature probe inside a panel, button it up and compare it to ambient air a few feet away. One of those little indoor/outdoor thermometers would work well for this. Maybe try the probe in different spots in the panel.
I use one of these thermometers when I am designing computer cases. They are pretty handy to see what is going on inside a closed box. Some of the nicer ones will also log high temp.
Greg Fretwell
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Joined: Jan 2005
Posts: 5,445 Likes: 3
OP
Cat Servant Member
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John, that's another thing that deserves considerable discussion, it's own thread, and crosses many forum boundaries.
I won't deny that we need to know the code. However ...
Each of us has a duty to know far more than the code ... we need to know how things work. How else can we design, apply the code, or perform troubleshooting?
Likewise, we all have a duty to participate in making the laws that we agree to honor. This means that we need to correct errors. Errors will not correct themselves.
Even within our own lifetimes there have been such errors corrected. Seatbelt interlocked ignitions and the 55mph speed limit are two examples that come to mind. Other matters are currently 'under review' by the populace; witness the continuing discord regarding both marijuana and abortion. Citizen participation is what drives all of these.
Now, regarding the AFCI, it sure looks like the basic premise behind the device has been called into question. Each of us has some opportunity to affect the adoption, expansion, and even the repeal of rules regarding the device. The "AHJ" can be many many different parties, but the NFPA certainly isn't one of them. Nor is UL or Square D.
No, the burden falls squarely on the AHJ. Those other 'interested parties' might be a useful resource, but that does not lessen the responsibility of the AHJ. Since we have set our country up as one where every AHJ derives its' authority from the consent of the governed, we all have the duty to monitor those we call "AHJ's."
IMO, Mr. Engle has certainly brought enough doubt to the table to justify suspending any AFCI enforcement until the matter is settled. Any AHJ that does not consider this matter is being irresponsible.
Don't give me the 'we're bound to enforce the law' malarky. Every bureaucracy has its' mechanisms for changing, interpreting, and enforcing the 'law.' Nor have bureaucracies had the slightest hesitation in being mighty selective in their applications; witness the current debate regarding 'pre-emption' with regard to immigration laws. On that topic, the "AHJ" has no problem ignoring one group of 'interlopers' while suing another.
"As AHJ, I have no recourse." Then you're not the AHJ. You simply represent the AHJ. If you have to do what the State tells you, then the State is the AHJ. At a minimum, you have a duty to ensure that those who adopt the rules have all the relevant information available to them. I'm pretty sure that means they have to listen to more viewpoints than just the one of the NFPA.
Likewise, we are all part of the code-making process. You know, that 'consensus-based' stuff they brag about. Some of us even are part of code panels. Well, there's a reason proposals get voted on- both in committee and on the convention floor.
These are serious matters. That's why I consider it so critical to examine Mr. Engle's paper so closely. If he's in error, we ought to be able to demonstrate the error. If he's right, the AFCI is a fraud.
This thread has examined only one of his assertions. So far, it looks like he is correct when he asserts that an 'arc fault detector' is no more possible than a time machine or anti-gravity paint.
His paper raises many other issues, each of which needs to be separately examined. I expect to see these issues raised in additional threads.
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Joined: Oct 2000
Posts: 5,392
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One concern I do have with such a widespread requirement for AFCI is building up so much heat in the panel, due to packing so many continuously operating (heat emitting) devices in a confined space. Are we going to be seeing 84 slot panel used for 42 circuits?
And what is the long term reliability of AFCI? We haven't seen them in long term (and in all that heat), yet.
I think I would rather see AFCI outlet devices, since at least for residences, cords for utilization equipment may be the greatest risk (not that a nail driven into an NM isn't a risk).
a deacade ago i had complaints of 'no load' heat emissions conferring with one of the brighter ahj's at the time (sadly retired) i was told space them out every other breaker this was version 1 btw last ahj who viewed my afci packed panel said that he was unsure if the manufacturer would have wished that i uncurled the white N pigtail it's an issue that's taken all my patience..... ~S~
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Joined: Oct 2000
Posts: 5,392
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John, that's another thing that deserves considerable discussion, it's own thread, and crosses many forum boundaries.
I won't deny that we need to know the code. However ...
Each of us has a duty to know far more than the code ... we need to know how things work. How else can we design, apply the code, or perform troubleshooting?
Likewise, we all have a duty to participate in making the laws that we agree to honor. This means that we need to correct errors. Errors will not correct themselves.
Even within our own lifetimes there have been such errors corrected. Seatbelt interlocked ignitions and the 55mph speed limit are two examples that come to mind. Other matters are currently 'under review' by the populace; witness the continuing discord regarding both marijuana and abortion. Citizen participation is what drives all of these.
Now, regarding the AFCI, it sure looks like the basic premise behind the device has been called into question. Each of us has some opportunity to affect the adoption, expansion, and even the repeal of rules regarding the device. The "AHJ" can be many many different parties, but the NFPA certainly isn't one of them. Nor is UL or Square D.
No, the burden falls squarely on the AHJ. Those other 'interested parties' might be a useful resource, but that does not lessen the responsibility of the AHJ. Since we have set our country up as one where every AHJ derives its' authority from the consent of the governed, we all have the duty to monitor those we call "AHJ's."
IMO, Mr. Engle has certainly brought enough doubt to the table to justify suspending any AFCI enforcement until the matter is settled. Any AHJ that does not consider this matter is being irresponsible.
Don't give me the 'we're bound to enforce the law' malarky. Every bureaucracy has its' mechanisms for changing, interpreting, and enforcing the 'law.' Nor have bureaucracies had the slightest hesitation in being mighty selective in their applications; witness the current debate regarding 'pre-emption' with regard to immigration laws. On that topic, the "AHJ" has no problem ignoring one group of 'interlopers' while suing another.
"As AHJ, I have no recourse." Then you're not the AHJ. You simply represent the AHJ. If you have to do what the State tells you, then the State is the AHJ. At a minimum, you have a duty to ensure that those who adopt the rules have all the relevant information available to them. I'm pretty sure that means they have to listen to more viewpoints than just the one of the NFPA.
Likewise, we are all part of the code-making process. You know, that 'consensus-based' stuff they brag about. Some of us even are part of code panels. Well, there's a reason proposals get voted on- both in committee and on the convention floor.
These are serious matters. That's why I consider it so critical to examine Mr. Engle's paper so closely. If he's in error, we ought to be able to demonstrate the error. If he's right, the AFCI is a fraud.
This thread has examined only one of his assertions. So far, it looks like he is correct when he asserts that an 'arc fault detector' is no more possible than a time machine or anti-gravity paint.
His paper raises many other issues, each of which needs to be separately examined. I expect to see these issues raised in additional threads. Reno perhaps the easiest avenue is to simply get Dr E's paper out there, and let the nonpartisans of the trade educate themselves and decide on a course collectively there are a lotta ways to do this, aside form the professional forums i'm sure i don't need to list them for anyone here ~S~
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Joined: Apr 2002
Posts: 7,381 Likes: 7
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The information and data within the discussions here is being correlated and intent is to forward same to those within the code adoption offices of the state.
As we (NJ) have lagged behind the majority of the ststes in adopting AFCI requirements, perhaps those that make the choices for the people will hear this issue & act accordingly.
John
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Joined: Oct 2000
Posts: 5,392
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Amen to that HotOne
as jaded and cynical as i have grown, i still hold out for those who would promote the altristic
we were, fwiw, in Vt a code cycle ahead of the nation, because our chief inspector at the time thought the afci God's gift to the trade
so did i, for a while
i've waited almost a decade for the likes of Dr. Engle , i've stood alone before the powers that be (and let me tell you. it's mighty lonely standing up to some of the trades respected silverbacks here) lamenting them publicly
i'd like the truth, the whole truth, and nothing but the truth
(gets off stump)~S~
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Joined: Apr 2002
Posts: 7,381 Likes: 7
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Reno:
I have to briefly comment here in this thread, and perhaps further via PM, email, or a venue of your choice if you care.
As an AHJ, I have no choice but to enforce the adopted codes. Yes, I may, or may not personally agree with the written word, but if I want to stay employed, I have to enforce what the state adopted.
Amending what is presently adopted is not going to be easy, perhaps IF & when the 2011 NEC is adopted, may be the next available chance, but....some things move slow.
Take care & stay safe.
John
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Posts: 3,682
Joined: October 2000
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