Hi Chris and William There was certainly no intention to mandate that all inverters connect to one OCPD/disconnect.But 705.12(B)(1) in 2017 clarifies that systems like Enphase could have multiple inverters on one breaker, certainly not that all inverters in a building have to be on breaker.
If an AHJ raises this issue the answer is as follows: A single inverter can be called a single PV system - see the diagrams in 690.1(b). A building can have multiple PV systems per 690.4(D). Each PV system can have no more than 6 system disconnect switches per 690.13(D). Circuit breakers are allowed as PV system disconnects - 690.13(F)(1). There is no limit to the number of PV systems allowed on a building. Therefore, each inverter can be connected to its own breaker/disco for that PV system. A few further comments : A single PV system can have a single inverter, or multiple inverters. It is up to you to define the system and the PV system disconnect(s) associated with it. OR multiple inverters (power sources) can be connected to a single OCPD/disco up to the manufacturer's maximum OCPD limit, per 705.12(B)(1). OR multiple (let's say 10) inverters in a single system can each have their own OCPD/disco and ONE master PV system disconnect for all 10 inverters to follow the fules of 690.13(D). Lots of options, all allowed! Best, Rebekah Principal, CMP-4 On Mon, Feb 25, 2019 at 5:31 PM Christopher Warfel < cwar...@entech-engineering.com> wrote: > Just reading more slowly, each inverter has to be on its on separate > disconnect means. You cannot put multiple inverters on the same > disconnecting means unless there are individual disconnecting means > upstream. > On 2/25/2019 10:53 AM, William Miller 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. > > > > This article > <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 > > 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 > > -- > Christopher Warfel > ENTECH Engineering, Inc. > PO Box 871, Block Island, RI 02807 > 401-466-8978 > <http://entech-engineering.com> > > > _______________________________________________ > 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 > > -- Tel: 336.266.8800 NABCEP Certified Solar PV Installation Professional™ 091209-85 NC Licensed Electrical Contractor
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