[RE-wrenches] Combining Multiple Inverters

[Corey Shalanski]

ᐧ
Perhaps I should've been more specific with my scenario. I was imagining a
supply side connection, as this would more commonly be the case when
combining multiple inverters. In this case it seems like the provisions of
705.12(D) for load side conections don't even apply, no? Rather 705.12(A)
becomes the relevant section, and I see very few restrictions there.

Even with a load side connection I would tend to agree with Jason's
interpretation: Does the "source interconnection" in 705.12(D)(1) refer to
each individual inverter, or can it refer to an aggregated "source"?

I am interested in pursuing this idea, mainly to understand how/where the
NEC forbids it. In lieu of a clear Code reference against it, how is this
any different from a branch circuit (in reverse)? ie, as with
microinverters.

--
Corey Shalanski
Joule Energy
New Orleans, LA

On Thu, Jun 26, 2014 at 9:20 AM, <re-wrenches-request at lists.re-wrenches.org>
 wrote:

>
> Message: 11
> Date: Thu, 26 Jun 2014 09:10:07 -0400
> From: Jason Szumlanski <jason at fafcosolar.com>
> To: RE-wrenches <re-wrenches at lists.re-wrenches.org>
> Subject: Re: [RE-wrenches] Combining Multiple Inverters
> Message-ID:
>         <
> CAJJtG3oQGBLzatinUHFp_GhivzYD6dLdsLAnkc1ofG9tR1RFgA at mail.gmail.com>
> Content-Type: text/plain; charset="utf-8"
>
> 705.12(D) reads, "... the interconnection provisions for the
> utility-interactive inverter(s) shall comply with (D)(1) through (D)(7)."
> That's inverters - plural. The interconnection must be protected by
> dedicated OCPD, not each inverter individually. Microinverters comply
> because of this interpretation.
>
> That said, I've never done it. An accumulator panel is pretty cost
> effective when you consider the alternative cost of an enclosure and the
> Polaris connectors. I guess if you are making the Polaris connections
> inside the main load center or inside an inverter you can eliminate the
> cost of a dedicated enclosure. There would be some material and labor
> savings.
>
> ?If the inverter has a maximum OCPD rating, you will be limited by that.
> ?Microinverters "get around" that by the wire and inverter being
> sized/rated for the entire maximum string.
>
> Jason Szumlanski
>
> ?Fafco Solar?
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