AFCI vs user

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Open Neutral

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A friend & fellow EE is remodeling; AHJ required AFCI and GFI's. He passed the electrical inspection but asked two questions:
  1. What's the backstory on the 5->30mA relaxation vs GFI's?
  2. How is he supposed to run his Skil Saw and/or hand drill when they trip the AFCI every time?

I'm a failure; I could answer neither, even after studying the FAQ. Can folks here help redeem me?
 
renosteinke

renosteinke

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It seems the 30mA GFI part of the AFCI unit is a consequence of the design, rather than a deliberately added feature. Oddly enough, there are places where you're required to use a 30mA GFCI, and the AFCI devices are NOT listed for those applications.

As for your tools, it is the position of NEMA and the AFCI manufacturers that there has NEVER been a false trip of an AFCI from a properly operating UL listed appliance. Prove it and be the first to shut them up- or just get some new tools.
 
charlie b

charlie b

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I don't have the 2008 or 2011 handy. Does a garage or workshop area require AFCI protection?
 
G

G._S._Ohm

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renosteinke said:
there has NEVER been a false trip of an AFCI from a properly operating UL listed appliance.
Click to expand...

IMO, this AFCI zero defects rate, or a zero defects rate in any other manmade device, is statistically impossible. Especially so with something that uses a very complex decision method such as signature analysis.

Siemens make an AFCI troubleshooting device. I'd be interested in how many TNFs [trouble not found] happens even with this using this tool.

I know at least one case where a nearby radio station set them off but the AFCI people only send you a filter if you ask for it.
 
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O

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charlie b said:
I don't have the 2008 or 2011 handy. Does a garage or workshop area require AFCI protection?
Click to expand...

He told me the inspector told him that "real soon now" virtually all other locations would also require them. Not a great source, I admit.

It's moot to him; but would be of interest.

His situation is the carpenters and other crafts working inside the bedrooms, etc. He comes back and they have tripped 4 or 5 breakers, and just moved to another circuit rather than reset them.
 
ptonsparky

ptonsparky

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The AFCIs are most likely working as designed. Tools with universal type motors are just going to.trip them. Get used to it and get over it. Quit whining. Find them a. Gfci protected circuit and walk away.

Oh, and email a state Senator with your concerns about them and see how long it takes for your phone to ring.
 
ActionDave

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ptonsparky said:
The AFCIs are most likely working as designed. Tools with universal type motors are just going to.trip them. Get used to it and get over it. Quit whining.
Click to expand...
I have not found this to be true. The one time I had a legitimate nuisance trip (no wiring errors) with an AFCI the problem seemed to be because of an electronic soft start in the tool. It would function on a GFCI protected circuit, but would trip every AFCI in the house.

I could plug in any other tool with a universal motor and the AFCI's would not trip. Table saw, router, angle grinder, none of these caused a problem.

One old Skil Saw would draw a big blue arc around the armature that you could use instead of a flash bulb to take a picture. No trip.
 
ActionDave

ActionDave

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ptonsparky said:
Combination style or otherwise? Can you prove it was not working as designed? My used to be favorite brand trips with universal motors. It doesn't mean they aren't functioning within design limits. Just means they are a PIA and I may have to change brands.
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That is the point I was trying to make. I believe in my case there was something in the electronics of the saw that the breaker interpreted as a dangerous arc. It probably was functioning as designed, just so happens the design is flawed.

The breaker I had trouble with was a Homeline combo type.
What is the breaker you are having trouble with?
 
ELA

ELA

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ptonsparky said:
CH & BR
I was thinking about changing to SQD products but hate to buy & find out they are a piece of junk as well. Buy a couple & test em myself I guess.
Click to expand...

I would be interested in hearing those results.
Do any AFCI manufacturers claim that their breaker will not work in the presence of another AFCI breaker?
If not then how about all three manufacturers in series :cool:
 
G

G._S._Ohm

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ELA said:
how about all three manufacturers in series :cool:
Click to expand...
Good experiment: all manufacturer's units in series, and hooked up to a dozen different kinds of loads and new and old appliances, one at a time.

In principle all should trip on bad arcs all at the same time, and never trip on good arcs. And if they don't, it puts to rest the idea that there has never been a false trip. Or, I guess, a case where an AFCI did not trip on a validly bad arc.

This would be a democracy of three.
How would they vote? More disturbingly, suppose they vote differently on different days because they respond differently to 'dirty' power or for who knows what reason?

This experiment is the same as if you hook ammeters all in series or voltmeters all in parallel. If you don't get the same readings on all, which are correct?

Are good arcs and bad arcs traceable to the NIST? Do they have machines that consistently produce both to some level of accuracy and repeatability?
 
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ELA

ELA

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G._S._Ohm said:
Good experiment: all manufacturer's units in series, and hooked up to a dozen different kinds of loads and new and old appliances, one at a time.
Click to expand...

I was kinda kidding as I think the ground fault portion of the breaker might not like a series arrangement. It would be great to substitute each breaker and try the very same loads though.
 
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