Hi Rebekah;
Thanks for pointing out the changes to the diagrams. I especially
appreciate Note (2). /The PV system disconnect in these diagrams
separates the PV system from all other systems./
That seems simple enough for defining the boundaries of RSS, until you
think about off grid, and look at the last diagram of 690.1(b) titled
"Stand Alone System". The charge controller is not shown at all. Then
Figure 690.1(a) shows a /DC to DC Converter (optional location)/, shows
a fuse after, shows the power going with an arrow to no where, on a line
labeled /PV or DC to DC converter output circuit...../ But finally, the
cause of my greatest confusion: it does not show the *PV System
Disconnect* anywhere.
I have several questions:
Is a charge controller a *DC to DC converter*? What about non MPPT
controllers that don't convert voltage?
Is a charge controller considered *DC* *utilization Equipment* mentioned
in the definition of *PV Output Circuit*, or is the inverter and DC
loads the utilization equipment?
All of which leads to the $20 thousand dollar question: Is the *PV
System Disconnect* before or after the charge controller?
If before the charge controller, where can the PV Disconnect be? Could
it be outside, at the pole, or does it need to be within 3 ft of the
building entry?
Even with all the changes made in 2017, it seems that we still are left
with too much uncertainty about where a PV circuit ends, or what
constitutes the "PV Disconnect" in an off grid system. Not such a big
deal, until we are required to apply 690.12.
Thanks everyone for your answers and opinions,
Ray Walters
Design Engineer
Remote Solar
On 4/17/18 7:15 AM, Rebekah Hren wrote:
Hi everyone,
I strongly recommend looking at the figures that were added in NEC
2017 at the beginning of Article 690 in 690.1(b).
What they show is equipment that is part of the PV system (to the left
of the PV system disconnect called out in the diagrams), and equipment
that is not part of the PV system (to the right of the PV system
disconnect). These are really helpful diagrams, in terms of figuring
out where the requirements of Article 690 apply.
Equipment *not* part of the PV system is not a "PV system circuit" and
thus is *not* subject to rapid shutdown requirements per 690.12.
In every type of system you will see that energy storage is *not *part
of the PV system, and neither is the multimode inverter for a system
with energy storage. So rapid shutdown requirements shouldn't affect
any of the loads, multimode inverter, or batteries in an off-grid system.
In the 2017 NEC, the PV system disconnect, as shown on the diagrams,
is required to be readily accessible per 690.13(A). For a system
without batteries, the PV system disconnect is *always *an AC
disconnect, not a DC disconnect. It can be the backfed breaker per
690.13(F)(1). For a system with batteries the PV system disconnect is
always before the batteries.
Equipment disconnects, like the DC inverter disconnect, are not
required to be readily accessible, but must be within 10 feet of the
equipment, per 690.15(A).
Also note that the boundary for rapid shutdown shrank to *one foot*
from the perimeter of the array in the 2017 NEC, so the inverter must
be positioned within one foot of the array if there is not going to be
any other RS equipment. The PV system disconnect (backfed breaker) or
the service disconnect can serve as the rapid shutdown initiation
device in that case.
Best,
Rebekah Hren, Member of NEC CMP-4 for Solar Energy International
--
Tel: 336.266.8800
NABCEP Certified Solar PV Installation Professional™ 091209-85
NC Licensed Electrical Contractor
On Mon, Apr 16, 2018 at 9:00 PM, Ray <r...@solarray.com
<mailto:r...@solarray.com>> wrote:
For GT using Solar edge or Enphase, its not so hard to comply, but
If you are looking at off grid systems, it's not just someone's
opinion, its $1,000s of dollars extra to comply with 690.12. It
also results in a system that is less reliable, which is less safe
off grid where lives depend on that power for heat, light,
refrigeration, and even breathing machines.
Ray Walters
Remote Solar
On 4/16/18 7:44 AM, Brian Mehalic wrote:
Hey y'all, I'm going to disagree about the NEC getting "worse and
worse when it comes to PV," (see disconnect and grounding
requirements, for instance!), but as with previous posters,
that's just an opinion.
Regarding location - the 2014 version had very little to say
about the location of any rapid shutdown initiation device; 2017
adds the requirement [690.12(C)] that RS initiation devices for
one- and two-family dwellings be readily accessible (defined in
Article 100), AND outside the building. Seems reasonable for a
device that is intended to control energized conductors to make
it more safe to enter a building.
Cheers,
Brian Mehalic
NABCEP Certified Solar PV Installation Professional™ R031508-59
520.204.6639
Solar Energy International
http://www.solarenergy.org
SEI Professional Services
http://www.seisolarpros.com <http://www.seisolarpros.com>
On Mon, Apr 16, 2018 at 12:04 AM, Mark Frye
<ma...@berkeleysolar.com <mailto:ma...@berkeleysolar.com>> wrote:
Thanks Darryl.
I guess I can add that I am in CA and so looked only at the
2014. I also looked at the 2017 article. Man, I have to say,
my impression remains that really starting with 2008 the code
has just gotten worse and worse when it comes to PV, but that
is just me.
Not really sure what might need to be "Outside readily
accessible". Is there something other than 690.12 that I need
to look at?
Mark
On 4/15/2018 8:26 PM, Darryl Thayer wrote:
I think the code says Outside readily accessible,
On Sun, Apr 15, 2018 at 12:22 PM, Mark Frye
<ma...@berkeleysolar.com <mailto:ma...@berkeleysolar.com>>
wrote:
Folks,
As I recall, an inverter and it's integrated DC
disconnect need only be placed in an accessible
location. I am thinking of putting an inverter high up
on the wall inside a garage. That would be OK vis-a-vis
the location of the disconnect (still accessible for
maintenance).
If I do put the inverter high up on the wall, I can
limit my DC conductors to less that 10 feet total from
the array and less that 5 feet inside the garage.
That means I get the exemption from the rapid disconnect
requirement, right?
There is nothing in the Code linking the accessibility
of the DC disconnect to the exemption from rapid
shutdown, right?
Mark Frye
_______________________________________________
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
<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
<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
<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
<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
<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
<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
<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
<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
<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
<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
