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
[EMAIL PROTECTED]
On 10/24/08 10:31 AM, "R. Walters" <[EMAIL PROTECTED]> 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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