[RE-wrenches] 690.31E (was Request for Enphase comments)

[R. Walters]

In my earlier post, I was about to make the claim that we could avoid  
the metal conduit with the Enphase inverters, then I reread it and  
saw that it covered inverter output as well.
It seems to me that the AC line is no more dangerous than any other  
AC branch circuit in the house, and should be treated as such.
Ahh, but the wording....I guess we have to wait till 2011 because of  
a typo?
Also, I'm not sure if PV is the best word choice. The AC output of  
the Enphase inverter could be considered to be PV by some AHJs. I  
think keep  DC, and drop the mention of inverter output completely.


Ray

On Oct 26, 2008, at 10:36 PM, Kelly Keilwitz, Whidbey Sun & Wind wrote:

> Hi Ray,
> I'm curious to know why you think that metallic conduit is required  
> for the
> inverter AC output. 690.31(E) specifically addresses DC source and  
> output
> circuits.
>
> We have an AHJ who interprets the section the same as you and I've  
> been
> working to turn him (as he's now responsible for training other  
> inspectors
> on PV in our Region). Toward that goal I asked John Wiles for his  
> input. He
> said:
>
> " The intent of 690.31(E) is to apply only to the always-energized DC
> circuits and not to the ac output circuits from the inverter since  
> they go
> "dead" as soon as the circuit to the utility is opened at any point.
> There was a typo in 690.31(E) in the 2008 NEC.  The word "of"  
> should have
> been "to" in front of the word "inverter".  The typo occurred in the
> original submission (by me) to the Code Making Panel. The typo was not
> detected during the review process.  The word "PV" modifies both  
> "source"
> and "output" .
> The attached proposal is being submitted for the 2011 NEC that will  
> make
> corrections and expansions to 690.31(E)."
>
> I'd be interested to know if other wrenches are being subject to  
> the same
> interpretation (i.e. inverter AC must be in metal).
>
> -Kelly
>
> Kelly Keilwitz, P.E.
> Whidbey Sun & Wind, LLC
> Renewable Energy Systems
> NABCEP Certified PV Installer
> 987 Wanamaker Rd,
> Coupeville, WA 98239
> PH & FAX 360-678-7131
> sunwind at whidbeysunwind.com
> On 10/24/08 10:31 AM, "R. Walters" <walters at taosnet.com> wrote:
>
>>
>>  You run AC wiring right to the AC disconnect from the roof. You  
>> still have to
>> comply with 690.31E, (steel conduit to the disconnect is required  
>> for both DC
>> or inverter output to the first readily accessible disconnect))  
>> but you only
>> need a single AC disconnect. No combiner box, No accessible DC  
>> disconnect.
>>
>>
>> Ray Walters
>>
>>
>
>
>
>
>
>
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R. Walters
Solarray.com
NABCEP # 04170442	



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