Newbie question re: Radian FM100 AFCI

Discussion about the FM100 AFCI Charge Controller
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MJSullivan56
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Newbie question re: Radian FM100 AFCI

Post by MJSullivan56 »

My electrician inquired about whether or not the 60A breaker on the service panel to the GSLC needs to be an AFCI breaker or not. I told him I didn't think so because the FM100 AFCI would take care of that requirement, but perhaps one still needs an AFCI breaker to be NEC 2020 code-compliant? Any insight appreciated.

Note: this is in regards to a pre-wired FPR-4048A-300AFCI unit.

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Re: Newbie question re: Radian FM100 AFCI

Post by fcwlp »

The FM100 AFCI is NEC 2017 compliant per OB literature. I have not seen the actual 2020 NEC (my county is still on 2011 :grin: ) but from the docs I reviewed that looked at the 2017 to 2020 deltas there appear to be no changes to section 690.11 which is for the arc fault requirements.

Putting another AFCI breaker in-line with FM100 AFCI input would appear redundant. I doubt if your electrician could even find a 60A DC AFCI breaker. There are combiner boxes that integrate arc fault from OB and others. The OB product is shown is here, https://www.outbackpower.com/products/s ... e-ics-plus.
MJSullivan56
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Re: Newbie question re: Radian FM100 AFCI

Post by MJSullivan56 »

Correct me if I’m wrong, but I thought AFCI was primarily an AC thing not a DC thing?

Also note: I should have originally stated “the 60A service panel breaker that powers the GSLC”.
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Re: Newbie question re: Radian FM100 AFCI

Post by raysun »

MJSullivan56 wrote: Thu Oct 28, 2021 6:34 pm Correct me if I’m wrong, but I thought AFCI was primarily an AC thing not a DC thing?

Also note: I should have originally stated “the 60A service panel breaker that powers the GSLC”.
AFCI is an Arc Fault thing. They can go both ways.

I've never wired to a GSLC, but the other OB panels I have used, the AC OUT wiring was protected with a "plain vanilla" AC breaker of the proper capacity.
MJSullivan56
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Re: Newbie question re: Radian FM100 AFCI

Post by MJSullivan56 »

So it would appear that here in Massachusetts where we have adopted NEC 2020, and where our local AHJ is pretty strict about the code, that the main service panel breaker powering my OB equipment will likely need to be AFCI — correct?

I only say this because my electrician said that the new focus is that pretty much every circuit should be AFCI and also GFCI wherever water is involved (e.g. kitchen, bathrooms, and outdoors.
Last edited by MJSullivan56 on Thu Oct 28, 2021 6:50 pm, edited 1 time in total.
raysun
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Re: Newbie question re: Radian FM100 AFCI

Post by raysun »

MJSullivan56 wrote: Thu Oct 28, 2021 6:47 pm So it would appear that here in Massachusetts where we have adopted NEC 2020, and where our local AHJ is pretty strict about the code, that the main service panel breaker powering my OB equipment will likely need to be AFCI — correct?
Grid AC IN to the GSLC/Inverters?

Above my pay grade. Best ask your electrician or the AHJ.
MJSullivan56
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Re: Newbie question re: Radian FM100 AFCI

Post by MJSullivan56 »

Well then what is the OB “300 AFCI” needed for if it would end up being redundant?
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Re: Newbie question re: Radian FM100 AFCI

Post by raysun »

MJSullivan56 wrote: Thu Oct 28, 2021 6:53 pm Well then what is the OB “300 AFCI” needed for if it would end up being redundant?
Are you talking about a pre-wired panel with an FM100 charge controller? Of so, that is likely a DC AFCI between the solar panels and the battery. Its not redundant to any AC wiring requirements, its there to keep your solar panels from burning your house to the ground.
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Re: Newbie question re: Radian FM100 AFCI

Post by MJSullivan56 »

As noted in my OP:

Note: this is in regards to a pre-wired FPR-4048A-300AFCI unit.

Perhaps rephrasing the question will help: does the FPR-4048A-300AFC provide AFCI protection on the AC out? Or only on the DC side?
MJSullivan56
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Re: Newbie question re: Radian FM100 AFCI

Post by MJSullivan56 »

Thanks. That answers my newbie question. Makes sense now.
raysun
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Re: Newbie question re: Radian FM100 AFCI

Post by raysun »

Its a best practice to avoid this:
Screenshot_20211028-162043_DuckDuckGo.jpg
raysun
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Re: Newbie question re: Radian FM100 AFCI

Post by raysun »

As noted in my OP:

Note: this is in regards to a pre-wired FPR-4048A-300AFCI unit.
Nobody reads OPs, we just read the equipment list in the OP's profile.
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