# Using AFCI breakers on generator power



## Kevin (Feb 14, 2017)

I think a megger would be your answer. 

Or a better generator like a 25kw wacker neuson.

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## mofos be cray (Nov 14, 2016)

You could just have a set of regular breakers that travel with you from job to job for that purpose. How often a they hitting your wire that this is your standard practice? Maybe you need bigger boxes so the wire isnt to the front of the box?


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## micromind (Aug 11, 2007)

If the voltage regulator on the gen is the capacitor type (it usually is on small units), then the gen produces a distorted waveform, not a sine wave. If the gen was the inverter type, the waveform is even worse. 

I don't know enough about AFCIs to know how they would be affected by a non-sine wave but I wouldn't be surprised if they can't handle it.


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## emtnut (Mar 1, 2015)

Kevin_Essiambre said:


> I think a megger would be your answer.
> 
> Or a better generator like a 25kw wacker neuson.
> 
> Sent from my Samsung using Tapatalk


Yep ... That or what crazy mofo said, and test with regular breakers.

I've seen crap chinese gens trip AFCIs , I guess the distorted waveform is seen by them and they don't like it.


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## Kevin (Feb 14, 2017)

emtnut said:


> Yep ... That or what crazy mofo said, and test with regular breakers.
> 
> I've seen crap chinese gens trip AFCIs , I guess the distorted waveform is seen by them and they don't like it.


I would test with a better generator over using normal breakers. AFCI protection will be the end device so test with that.

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## nrp3 (Jan 24, 2009)

I've seen some trouble with AFCI tripping with power outages and not being able to replicate it. Not sure if its the utility side or something else. Not sure that the generator power is a good way to test the circuits initially.


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## Kevin (Feb 14, 2017)

nrp3 said:


> I've seen some trouble with AFCI tripping with power outages and not being able to replicate it. Not sure if its the utility side or something else. Not sure that the generator power is a good way to test the circuits initially.


Not sure what your circumstances are, but we had a sub-panel once with arc fault breakers. All of them starting tripping. The cause was arcing on the breaker feeding this sub-panel.

Maybe there's some arcing happening upstream and the arc fault can see/feel it? It would be something beyond your control though.

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## MTW (Aug 28, 2013)

Dirty power wreaks havoc on AFCI's, just like everything else does.


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## sbrn33 (Mar 15, 2007)

Kevin_Essiambre said:


> I think a megger would be your answer.
> 
> Or a better generator like a 25kw wacker neuson.
> 
> Sent from my Samsung using Tapatalk


So you are gonna megger these circuits? You think every circuit was bad? 
Just out of curiosity how long would that take for an 8 plex with temp lighting and GFCI's


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## Kevin (Feb 14, 2017)

sbrn33 said:


> So you are gonna megger these circuits? You think every circuit was bad?
> 
> Just out of curiosity how long would that take for an 8 plex with temp lighting and GFCI's


I wouldn't. I would get a better generator to test it. I was merely providing multiple options.

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## gpop (May 14, 2018)

Lots of new homes have back up generators that don't trip the arc fault breakers and the fact the breakers didn't trip till they had been on for a few minutes seems odd. 

Personally i would have taken one breaker from the panel and wired it to the generator as a quick and dirty test then run a drill/coffee pot as a load to see what happens. 

If you look at a quality generator on a scope the wave isnt as smooth as grid power so that may affect the afci


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## nrp3 (Jan 24, 2009)

I've had this happen with a couple of my customers homes and not been able to duplicate it. It always works fine while I'm there of course. I don't know whether it happens before the outage, when the switch transfers or after. Never been able to see it in person or duplicate it.


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## 918electrician (Dec 10, 2014)

I'm using a pretty nice generac generator. What do you all suggest to test and make sure cables are good. I like the changinging out to regular breakers but I make up panels as we go when roughing. These are plug on nuetral breakers so putting in normal breakers and then changing out to afci is a lot of work. do most of you guys hot test or do you guys just rough-in and then fixed issues after trim out?


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## Kevin (Feb 14, 2017)

918electrician said:


> I'm using a pretty nice generac generator. What do you all suggest to test and make sure cables are good. I like the changinging out to regular breakers but I make up panels as we go when roughing. These are plug on nuetral breakers so putting in normal breakers and then changing out to afci is a lot of work. do most of you guys hot test or do you guys just rough-in and then fixed issues after trim out?


Generac generators are not exactly high end. I'd either use a true sine wave inverter generator ($$$$$) or one of these wacker neuson rental generators (they've got pretty clean output).

There is the possibility that there's just something wrong with all your circuits...


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## sbrn33 (Mar 15, 2007)

There is the possibility that there's just something wrong with all your circuits...[/QUOTE said:


> This is true. especially if every place is made up the same. Mixed neutrals in the same box in each unit would do this.


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