AFCI protection might have prevented 34 deaths - California

rambojoe said:
A arc can glow... it happens through non-conductive material. Everyone here knows how a lightbulb works. Im with calling it a "glow arc" is folly but since you are for wiki and the such- look at lab created arcs on video...
I dont know, seems all views on the subject are interesting seeing that electrical dangers are sorta our doctrine here...
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Which is exactly what we have in HID and fluorescent lamps. Those happen to have the arc flowing through specific gases to help enhance how things operate vs just having an arc in the ambient air.
 
jaggedben said:
To me that's just not an arc, whatever is happening, and I will not be persuaded to starting using the term that way. An arc is what you see from plasma, however brief. Lightning is an arc, lighting is not. 😉 However I grant that that is clearly that is not a consensus understanding, and I can't force you not to use the word for things I never would, I just think it muddles the discussion around arc-fault breakers.
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You still think i like the word glow arc... do you read? I am not for the word..
 
Joe.B said:
Who knows the reason, but "video unavailable" is a statement of it's own...
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It is only unavailable for embedding in another web page. If you click the "Watch on You Tube" link it comes up just fine.
I think the intention is to force any viewer to see the ads associated with the actual You Tube page.
 
They also saved us from imminent alien attack. ET was about to do a fly by when he found out about these afcis and decided it would be a good idea to stay away. Good thing we installed them.
 
ActionDave said:
Where does the glowing come from? An arc or something else?
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That's a good question because 120 volts is supposedly not enough to sustain a true arc. Guessing then that whatever material is making contact is not large enough for the current flow, so it glows as in a heating element. Damage continues to grow or stops at some point. Frequently enough at the box connector if NM cable
 
ActionDave said:
Where does the glowing come from?
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Blackbody radiation.

Heat anything up to 1000F (very roughly) or more, and its blackbody emissions will start to become visible. That's the reason an electric resistance stovetop element will turn red. And how incandescent light bulbs work, and why color spectrums are measured in temperature.

Cheers, Wayne
 
ptonsparky said:
Glowing connection may be more appropriate but from my experience it looks like a little red welding arc.
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If you've done arc welding and gas welding you know the difference, and why the first one has a different name than the second, and needs a much higher shade mask.
 
jaggedben said:
I don't know where this idea comes from but I think it's misleading.
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If self sustaining arcs are possible at 120 volts, why does 230.95 only apply to systems over 150 volts to ground? When that rule went into the code, the reasoning was self sustaining arcing ground faults do not exist below 150 volts to ground and so a 208Y/120 volt system does not require the ground fault protection that is required for a 480Y/277 volt system in 230.95 and various other sections of the code.
 
don_resqcapt19 said:
If self sustaining arcs are possible at 120 volts, why does 230.95 only apply to systems over 150 volts to ground? When that rule went into the code, the reasoning was self sustaining arcing ground faults do not exist below 150 volts to ground and so a 208Y/120 volt system does not require the ground fault protection that is required for a 480Y/277 volt system in 230.95 and various other sections of the code.
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1. Glowing connections result from ohmic heating at junctions where the contact resistance is, for some reason, excessive. The most common cause, I believe, is a metal to metal connection which has partially separated, leaving a small, low pressure contact area.
2. To sustain an arc in air at atmospheric pressure, the voltage gradient at the peak of the AC waveform has to be high enough to break down and ionize the air in the gap, since the current drops to zero twice each cycle and the ionized plasma dissipates. In theory an arc can start at a low voltage as long as the gap is small enough, but in practice such a situation is not stable and cannot sustain an arc. If the electrode surfaces are eroded by the arc to form a cloud of metal vapor, the same limiting conditions do not apply once the arc has started.
 
GoldDigger said:
1. Glowing connections result from ohmic heating at junctions where the contact resistance is, for some reason, excessive. The most common cause, I believe, is a metal to metal connection which has partially separated, leaving a small, low pressure contact area.
2. To sustain an arc in air at atmospheric pressure, the voltage gradient at the peak of the AC waveform has to be high enough to break down and ionize the air in the gap, since the current drops to zero twice each cycle and the ionized plasma dissipates. In theory an arc can start at a low voltage as long as the gap is small enough, but in practice such a situation is not stable and cannot sustain an arc. If the electrode surfaces are eroded by the arc to form a cloud of metal vapor, the same limiting conditions do not apply once the arc has started.
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Bbut glowing connections are not arcs and even UL says that an AFCI will not detect and clear a glowing connection. That is simply joule heating and there is nothing on the market that can detect and clear that type of fault.
 
don_resqcapt19 said:
Bbut glowing connections are not arcs and even UL says that an AFCI will not detect and clear a glowing connection. That is simply joule heating and there is nothing on the market that can detect and clear that type of fault.
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A glowing connection is not too different from a resistive heater element intentionally glowing infrared hot. They need to make some sort of inconvenient technical innovation to solve this, like a thermometer sense wire that runs along the entire length of the NM cable.
 
ruxton.stanislaw said:
Here's a controversial question: how many deaths did AFCI cause, from needless loss of power or other circumstances?
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Probably not any direct deaths, but definitely a significant shortening of lifespan and quality of life spread across many electricians due to higher blood pressure stress and frustration - much like environmental mercury from burning coal and lead from leaded gasoline, significant damage but very spread out across the entire population.
 
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