The original question was w/r to:**/The source interconnection of one or
more inverters installed in one system shall be made at a dedicated
circuit breaker or fusible disconnecting means./
and whether one disconnect could be used to disconnect multiple
inverters. The inference as I read it was that there was no other
disconnect means for the inverters in question.
If you use an AC combiner upstream of the disconnecting means with
individual OCPDs as required, then you have your individual
disconnection and that is required and has been practiced for many code
cycles. A circuit breaker OCPD is a code compliant disconnecting means.
I cannot imagine anyone using an AC combiner method and not using OCPDc.
Using a disconnecting means to then disconnect downstream AFTER an AC
combiner is of course allowed. Chris Warfel
/
/
On 2/27/2019 1:48 PM, William Miller wrote:
Chris:
The 2014 code would require individual disconnecting means prior to
aggregation, i.e. an AC combiner. Therefore your scenario would not
exist.
Wm
*From:*RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org
<mailto:re-wrenches-boun...@lists.re-wrenches.org>] *On Behalf Of
*Christopher Warfel
*Sent:* Wednesday, February 27, 2019 10:43 AM
*To:* re-wrenches@lists.re-wrenches.org
<mailto:re-wrenches@lists.re-wrenches.org>
*Subject:* Re: [RE-wrenches] Multiple inverters
I know I keep popping up on this, but 2014 makes no sense if it is
saying to connect multiple inverters to one disconnect. It would be
difficult and dangerous to take one out of service for any reason
including replacement. I would that that you'd have to shut down all
the inverters just to replace one. Some of the large
commercial/industrial/utility systems have hundreds of inverters and
there is no way they would install a system to this interpretation of
the NEC.
On 2/27/2019 12:22 PM, Starlight Solar Power Systems wrote:
William,
It seems this question needs to be addressed: What is the intended
meaning of “installed in one system” in 2014? If you have separate
“systems”, they should not be governed by 705.12. So, at what
point does a “system” begin and end? PV modules to the disconnect?
...to the load panel? ...to the service entrance?
Larry
On Feb 25, 2019, at 10:42 PM, William Miller
<will...@millersolar.com <mailto:will...@millersolar.com>> wrote:
August:
The 2014 code, which the AHJ for this project is using, states the
following:
(/1) Dedicated Overcurrent and Disconnect. The source/
/interconnection of one or more inverters installed in one/
/system shall be made at a dedicated circuit breaker or fusible/
/disconnecting means./
Note that the language says, “The source interconnection…”
(singular), and “at a dedicated circuit breaker…”(again
singular). This makes it obvious to me that the language says
that the outputs of multiple inverters need to be aggregated and
connected via_one_OCPD. I think the other wrenches missed this point.
Your input is valuable by contrasting the language of the 2014
code with that of the 2017 version. The inclusion of the phrase
“Each source…” in the 2017 code completely changes the meaning.
Some AHJs will look to future code versions for clarity even if
they are not yet adopted. I think this is a good thing, and I
really appreciate you bringing up the new language.
The article from AEIA magazine ratifies the conclusion I drew from
the 2014 code. Fortunately the AHJ is misinterpreting the section
to allow the more liberal interpretation, the one that the 2017
code reflects. I find it best to contact the plan checker
directly, which I did, and we are approved for multiple OCPDs. By
the way, I think that article is well written and I have book
marked it.
I don’t know if the 2014 language was a mistake corrected in 2107,
or what the thinking was of the authors. Regardless, we live by
the language, not the intent.
Thank you as well to all who responded.
William Miller
*From:*August Goers [mailto:aug...@luminalt.com
<mailto:aug...@luminalt.com>]
*Sent:*Monday, February 25, 2019 9:07 AM
*To:*William Miller; RE-wrenches
*Subject:*Re: [RE-wrenches] Multiple inverters
Hi William -
In this case, it is helpful to look forward to the 2017 NEC for
guidance:
<image001.png>
I believe it's perfectly fine to have multiple inverter breakers
in your main.
August
Luminalt
On Mon, Feb 25, 2019 at 8:42 AM William Miller
<will...@millersolar.com <mailto:will...@millersolar.com>> wrote:
Friends:
I have an NEC code question on an upcoming project. It is a
home that has an existing 8 kW ground-mounted grid-tied
system. The owner wants to add another 10 kW of grid-tied
PV. My question is about 705.12, point of connection.
Specifically section (D)(1). That section states:
/The source interconnection of one or more inverters installed
in one system shall be made at a dedicated circuit breaker or
fusible disconnecting means./
So if there are going to be two inverters on premise, do the
outputs have to be aggregated to connect via one circuit
breaker? This might be difficult to do as the exiting
inverter is connected via a different sub-panel than the one
that is planned to receive the new inverter output.
Thisarticle
<https://iaeimagazine.org/magazine/2014/01/16/load-side-pv-connections/>addresses
the question.
I would be very grateful if any of you can share any
experience you might have in interpreting this section of the
code.
Thanks in advance.
William
_______________________________________________
List sponsored by Redwood Alliance
List Address:RE-wrenches@lists.re-wrenches.org
<mailto:RE-wrenches@lists.re-wrenches.org>
Change listserver email address & settings:
http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
List-Archive:http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html
List rules & etiquette:
www.re-wrenches.org/etiquette.htm
<http://www.re-wrenches.org/etiquette.htm>
Check out or update participant bios:
www.members.re-wrenches.org <http://www.members.re-wrenches.org/>
_______________________________________________
List sponsored by Redwood Alliance
List Address:RE-wrenches@lists.re-wrenches.org
<mailto:RE-wrenches@lists.re-wrenches.org>
Change listserver email address & settings:
http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
List-Archive:http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html
List rules & etiquette:
www.re-wrenches.org/etiquette.htm
<http://www.re-wrenches.org/etiquette.htm>
Check out or update participant bios:
www.members.re-wrenches.org <http://www.members.re-wrenches.org/>
_______________________________________________
List sponsored by Redwood Alliance
List Address:RE-wrenches@lists.re-wrenches.org
<mailto:RE-wrenches@lists.re-wrenches.org>
Change listserver email address & settings:
http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
List-Archive:http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html
List rules & etiquette:
www.re-wrenches.org/etiquette.htm
<http://www.re-wrenches.org/etiquette.htm>
Check out or update participant bios:
www.members.re-wrenches.org <http://www.members.re-wrenches.org>
_______________________________________________
List sponsored by Redwood Alliance
List Address: RE-wrenches@lists.re-wrenches.org
Change listserver email address & settings:
http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
List-Archive:
http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html
List rules & etiquette:
www.re-wrenches.org/etiquette.htm
Check out or update participant bios:
www.members.re-wrenches.org
_______________________________________________
List sponsored by Redwood Alliance
List Address: RE-wrenches@lists.re-wrenches.org
Change listserver email address & settings:
http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
List-Archive:
http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html
List rules & etiquette:
www.re-wrenches.org/etiquette.htm
Check out or update participant bios:
www.members.re-wrenches.org
