[RE-wrenches] Two NEC questions

[David Brearley]

RE Question #2: 

Article 100 defines a service as:

Service. The conductors and equipment for delivering electric energy from the serving utility to the wiring system of the premises served. (emphasis added)

PV system wiring simply does not fit that definition. The PV system is not part of the serving utility. And inverters are not service equipment. 

You need to refers them to this definition in Article 705.2 (added in NEC 2011):

Power Production Equipment. The generating source, and all distribution equipment associated with it, that generates electricity from a source other than a utility supplied service. (emphasis added)

FWIW: Mike Holt has written for SP about the Code requirements for interconnecting PV systems, as well as some additional recommendations for making supply side connections:

http://solarprofessional.com/article/?file=SP5_1_pg14_QA&search=


RE Question #1: I had a local inspector ask me about this in late-August & there were relatively few listed products at that time:

SMA America has dc AFCI in their standard SunnyBoy US-series inverters (SB 3000-US, SB 3800-US, SB 4000-US, SB 5000-US, SB 6000-US, SB7000-US, SB 8000-US): http://www.sma-america.com/en_US/news-information/current-news/news/news/1487.html
Microinverter systems (Enphase, Enecsys, etc.) typically do not operate above 80 Vdc and are therefore exempt from 690.11
AC module systems (powered by SolarBridge, Exeltech, etc.) typically do not operate above 80 Vdc and are therefore exempt from 690.11
SolarBOS reportedly has a dc AFDI and GFI combiner box: http://www.solarbos.com/news/solarbos-puts-out-the-fire-in-pv-systems (However, I don't see this product on their website under their regular lists of products.)
While module-level dc-to-dc converters—like those from SolarEdge and Tigo Energy—presumably have the ability to provide dc AFCI capabilities, last I checked it didn't look like any of them were formally listed to do so.

I suspect that most manufacturers are trying to avoid spending additional money on testing until the market requires this. 

Have any wrenches here actually had an inspector required dc AFCI? Also, is the dc AFCI test standard actually finalized and adopted at this point or are companies testing to a draft standard? 

David Brearley, Senior Technical Editor
SolarPro magazine 
NABCEP Certified PV Installer ™
david.brearley at solarprofessional.com
Direct: 541.261.6545


On Oct 13, 2012, at 10:12 AM, Rebecca Lundberg wrote:

> Dear fellow wrenches,
> 
> Does anyone have suggestions for the 'best' way to keep up with product availability for meeting 690.11 on DC AFCI? I understand that when this code section was written there was no available device, and know that at least several companies are working on devices. How will I know (before the AHJ knows :-) that residential-scale products are available for purchase, and at what point would you say now should be required over every other option?
> 
> Second question: I have an inspector insisting that the solar PV system is the same as a utility service, and is requiring all of the required service code references to apply. Anybody have a concise reference that might convince him otherwise? This same inspector has decided that the electrical permit will have adders for each inverter as service equipment, and each module as an electrical device. It would sure be nice if there was more consistency...we're still in the early adopter phase here in Minnesota.
> 
> Thanks in advance for your input.
> 
> Keep Shining!
> Rebecca Lundberg
> NABCEP Certified Solar PV Installer ®
> Owner/CEO, Powerfully Green
> Rebecca.Lundberg at PowerfullyGreen.com
> 763-438-1976
> 
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