AFCIs- at least they are now somewhat honest

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mbrooke

mbrooke

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Siemens finally admitted that standard circuit breakers and GFCIs provide combination arc fault protection. In other words the intent 210.12 could have been fulfilled with a GFCI or GFP circuit breaker.


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mbrooke said:
Siemens finally admitted that standard circuit breakers and GFCIs provide combination arc fault protection. In other words the intent 210.12 could have been fulfilled with a GFCI or GFP circuit breaker.


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How are you getting that? Aren’t combination AFCIs still required to trip on series arcing faults which is the one thing breakers can’t do? If properly sized agreed breakers can trip on parallel arcing faults. Outside of residential that’s the way we’ve always do it. A “parallel” arcing fault can be as low as 40% of short circuit.
 
paulengr said:
How are you getting that? Aren’t combination AFCIs still required to trip on series arcing faults which is the one thing breakers can’t do? If properly sized agreed breakers can trip on parallel arcing faults. Outside of residential that’s the way we’ve always do it. A “parallel” arcing fault can be as low as 40% of short circuit.
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:mad: I meant branch feeder. But yes, you're correct.

RMS wise. Peak wise the magnetic pickup will clear and arc fault in 1.5 cycles which fulfills UL1699.
 
romex jockey said:
well they're 'required' , but ......they don't Paul

~RJ~
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No disagreement there. Instead of arguing about the high false positives and negatives though how about the fact that there is no evidence for the purported screw that hits the wiring causing a fire or the fact that there is no statistical evidence they work?
 
paulengr said:
No disagreement there. Instead of arguing about the high false positives and negatives though how about the fact that there is no evidence for the purported screw that hits the wiring causing a fire or the fact that there is no statistical evidence they work?
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well......that's a long story Paul. The stats collected by the fire service, for one, aren't universally funded😟, add to that any forensic(s) aren't exactly universally applied.🤫.....save when it's all marketed to us by manufactures......😒i'm sure you get the gist of all that.......~RJ~
 
mbrooke said:
RMS wise. Peak wise the magnetic pickup will clear and arc fault in 1.5 cycles which fulfills UL1699.
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Regularly see 50yr old Zinsco plug-in's in mobile-home pedestals Mag trip before sub-panel breakers, with Siemens or most anything else. The notable exception is when Sqaure-D QO breakers are in the house.

As amazing as some of these Mag-trip functions are, never seen any of them catch burning aluminum branch wiring like this below:

Fireplace box.jpg

The fastest known Mag-trip breakers in existence allowed this box to smoke & burn up like a fireplace mantle. The idea that much slower Siemens breakers do better to prevent this kind of electrical fire has not been observed in my 15 yrs in the field.

Devices like this below, installed per 406.4(D)(4), are the only thing I've seen interrupt this kind of burnt or loose wire.

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Arcing and short circuiting tends to be the end stage of joule heating, assuming a fire hasn't already started.
 
Beware, my clients occasionally report sparks & smoke from copper wire.

Zoom in on burnt neutral wire below. That's solid #12cu, no copper-clad, or aluminum anywhere in this house.

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Standard breakers let this copper wire burn up inside the bakelite box.

When AFCI's trip on similar damage, and unskilled labor cant find it, much less get past inspection, residential Electrical Contractors and their Home Builder's Association have successfully lobbied to remove AFCI's by amendment, rather than train talent to fix existing wiring, or pull armored cable to metal boxes.

If they dared to train them they could walk, and work for themselves the way I did.
 
ramsy said:
Beware, my clients occasionally report sparks & smoke from copper wire.

Zoom in on burnt neutral wire below. That's solid #12cu, no copper-clad, or aluminum anywhere in this house.

View attachment 2555292

Standard breakers let this copper wire burn up inside the bakelite box.

When AFCI's trip on similar damage, and unskilled labor cant find it, much less get past inspection, residential Electrical Contractors and their Home Builder's Association have successfully lobbied to remove AFCI's by amendment, rather than train talent to fix existing wiring, or pull armored cable to metal boxes.

If they dared to train them they could walk, and work for themselves the way I did.
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But how much damage is done before the AFCI responds to it? Like earlier mentioned joule heating usually goes on and finally ends with short circuit or arcing.
 
When called out for AFCI trouble, extension cord, power strip, and appliance issues can be invisible, and pass 100v megger.

Most extension cord failures only trip reset devices while smashed under furniture or chairs. The only evidence with some festoon lighting was wire insulation separating from sockets & cord caps, exposing conductors until tension was removed.

Another common issue is painting the bus stabs during remodel and tenant turnover. Zoom in on 3rd stab down from top.

A5783AAA-7F01-4CD6-A19B-0C0991A744A1.jpeg

The exploit of unskilled labor is so critical to property managers, that damaged equipment is preferred to paying market rates for the skilled trades.
 
ramsy said:
When called out for AFCI trouble, extension cord, power strip, and appliance issues can be invisible, and pass 100v megger.

Most extension cord failures only trip reset devices while smashed under furniture or chairs. The only evidence with some festoon lighting was wire insulation separating from sockets & cord caps, exposing conductors until tension was removed.

Another common issue is painting the bus stabs during remodel and tenant turnover. Zoom in on 3rd stab down from top.

View attachment 2555296

The exploit of unskilled labor is so critical to property managers, that damaged equipment is preferred to paying market rates for the skilled trades.
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I doubt they want damaged equipment, but they have to know in this case that that is potentially damaging to begin with. When that fails months or years down the road it becomes "cheap junk they make nowadays in their mind". Plus it difficult to say this coating (which maybe looks more like texture overspray than paint) is absolute reason for failure, though you can't deny it is possible either, partly because same thing does happen occasionally with no foreign material on the bus. If brand new loadcenter and brand new breaker and failure in less than maybe 3-5 years though - the chances of foreign material being the problem goes up pretty dramatically I'd think.
 
ramsy said:
When called out for AFCI trouble, extension cord, power strip, and appliance issues can be invisible, and pass 100v megger.

Most extension cord failures only trip reset devices while smashed under furniture or chairs. The only evidence with some festoon lighting was wire insulation separating from sockets & cord caps, exposing conductors until tension was removed.

Another common issue is painting the bus stabs during remodel and tenant turnover. Zoom in on 3rd stab down from top.

View attachment 2555296

The exploit of unskilled labor is so critical to property managers, that damaged equipment is preferred to paying market rates for the skilled trades.
Click to expand...
So what, they removed the dead front before they painted?!? :unsure:
 
Always find fuse box & buss painted like this, when troubleshooting. The painters are long gone by the time I get there.

All apartments in Southern California have fuse box & bus stabs loaded with paint.

Doesn't matter what city, or who manages it, laborers must believe the breakers slide on easier with some fresh paint for lubricant. :cool:
 
ramsy said:
Always find fuse box & buss painted like this, when troubleshooting. The painters are long gone by the time I get there.

All apartments in Southern California have fuse box & bus stabs loaded with paint.

Doesn't matter what city, or who manages it, laborers must believe the breakers slide on easier with some fresh paint for lubricant. :cool:
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I thought most residential panels are typically all in ones located on the exterior in So Cal?
 
Thats right, and for multi-tenant buildings the outdoor meter centers include main disconnects, with those painted ML sub-panels in each unit.

Laborers didn't mess with meter centers in the past, but recently property managers are insisting their laborers watch me work.

Sending them on parts runs helps, but once Mgmt. finds my supplier for their equipment I rarely hear from them again.
 
ramsy said:
Thats right, and for multi-tenant buildings the outdoor meter centers include main disconnects, with those painted ML sub-panels in each unit.

Laborers didn't mess with meter centers in the past, but recently property managers are insisting their laborers watch me work.

Sending them on parts runs helps, but once Mgmt. finds my supplier for their equipment I rarely hear from them again.
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So order parts from some warehouse in another state and send them after it :)
 
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