Hopefully this will kill AFCI

Merry Christmas

mbrooke

Batteries Included
Location
United States
Occupation
Technician
STD breakers don't see propagating wave forms from all directions.

A solitary Leviton AFCI outlet, per 406.4D4, typically trips when Plug-on breakers start burning up a bus stab, so critical maintenace can avoid further destruction.

Panel flippers want to replace the box, wont pay for skilled talent, and have financial incentive to let it burn down.


In my opinion series arcing is the end stage of joule heating, provided combustion has not already initiated. Better splices, connections (screw vs back stab) and bus grabs would be a better solution than mandating costly devices which do not address the fundamental core issue at hand.

I think if someone was going to incorrectly install equipment out of indifference or lack of knowledge, they probably won't install AFCIs either.
 

ramsy

Owner/Operator
Location
LA basin, CA
Occupation
Service Electrician 2017 NEC
In my experience, unqualified negligence, whether unskilled, exploited, or both, is the fundamental core issue at hand.

Those who refuse to hire skilled labor, have the most to lose with AFCI's, which have no tolerance for poor skills or workmanship.
 

yuhong

Member
Location
Burnaby, BC
In my opinion series arcing is the end stage of joule heating, provided combustion has not already initiated. Better splices, connections (screw vs back stab) and bus grabs would be a better solution than mandating costly devices which do not address the fundamental core issue at hand.

I think if someone was going to incorrectly install equipment out of indifference or lack of knowledge, they probably won't install AFCIs either.
I assume that it is the arcing that starts fires not joule heating, right?
 

mbrooke

Batteries Included
Location
United States
Occupation
Technician
I assume that it is the arcing that starts fires not joule heating, right?


Joule heating starts fires. The connection glows red hot. It is not until annealing and metal deformation takes place before arcing presents itself. By then the connection has been sitting at +1080*C for some time.
 

yuhong

Member
Location
Burnaby, BC
Joule heating starts fires. The connection glows red hot. It is not until annealing and metal deformation takes place before arcing presents itself. By then the connection has been sitting at +1080*C for some time.
I am assuming that the wire already has been burned, of course. The question is whether this would be enough to start a fire.
 

kwired

Electron manager
Location
NE Nebraska
I am assuming that the wire already has been burned, of course. The question is whether this would be enough to start a fire.
Every instance of this happening has it's own circumstances. If something combustible is close enough then it starts on fire.

Bad connection in the panel breaker to bus connection - probably burns itself to open circuit condition nearly every time, not too often does anything combustible get close enough. In a device box, those often burn clear but not always. Plastic boxes, the device material, the conductor insulation, etc. are all flame resistant but still burn if they get hot enough. Then factor in time, dust/lint accumulation and there is higher risks of starting fires also.
 

yuhong

Member
Location
Burnaby, BC
Every instance of this happening has it's own circumstances. If something combustible is close enough then it starts on fire.

Bad connection in the panel breaker to bus connection - probably burns itself to open circuit condition nearly every time, not too often does anything combustible get close enough. In a device box, those often burn clear but not always. Plastic boxes, the device material, the conductor insulation, etc. are all flame resistant but still burn if they get hot enough. Then factor in time, dust/lint accumulation and there is higher risks of starting fires also.
And compare the cost of repairing the damage to those started by arcing.
 

yuhong

Member
Location
Burnaby, BC
Every instance of this happening has it's own circumstances. If something combustible is close enough then it starts on fire.

Bad connection in the panel breaker to bus connection - probably burns itself to open circuit condition nearly every time, not too often does anything combustible get close enough. In a device box, those often burn clear but not always. Plastic boxes, the device material, the conductor insulation, etc. are all flame resistant but still burn if they get hot enough. Then factor in time, dust/lint accumulation and there is higher risks of starting fires also.
And I assume that metal conduit would at least address the risk of dust accumulation, right?
 

kwired

Electron manager
Location
NE Nebraska
And I assume that metal conduit would at least address the risk of dust accumulation, right?
yes but yet you shouldn't have a connection within the conduit that can potentially fail.

Typical indoor boxes have mounting holes or other openings and though maybe not combustible themselves still can allow combustible material to get inside.
 
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