I may be playing devil's advocate here, but I want to add a few thoughts. Jay, I
just looked at Fronius and SMA inverter data sheets. I found no spec. for an
output OCPD, only a spec for max. output current.
William, most inverters now come with integrated DC/AC discos. Dave, 2014 NEC
705.12(D)(1), IMHO, specifies ONE OCPD for the entire interconnected power
system, not individual OCPD for each inverter.

Generally speaking OCPD is provided for the circuit conductors in a system, not
the individual pieces of equipment. If the equipment manu. specifies OCPD, that
is a different story.

I understand the 2014 code to require appropiate OCPD for all the conductors
from the panelboard to the inverter. If that can be accomlished with one device
at the panel, it meets code. That said, code is a MINIMUM standard.

Bottom line, I agree with Corey that there is no code requirement for individual
OCPD for each inverter. If there is, unfortunately, it is insufficiently
explicit such that we are having this conversation.

Dick Ratico
Solarwind Electric


--- You wrote:
I have never seen an inverter that does not specify a OCPD size. 

Jay
Peltz power. 

Sent from my iPhone

> On Jun 26, 2014, at 3:20 PM, Dave Click <daveclick@fsec.ucf.edu> wrote:
> 
> Corey,
> 
> The line of reasoning is faulty. It's 705.12(D)(1). Micro-inverters are the
exception because they are specially listed to share a breaker. As for the other
inverters, doubling them up on a single breaker / disconnect probably goes
against their installation instructions [110.3(B)] and it's unlikely that you
could put multiple units on a single breaker anyway because when you take (2
inverters) x (rated current) x (1.25) you will probably come up with a minimum
breaker size that is larger than the maximum allowed under the NRTL listing to
UL 1741.
> 
> Dave
> 
> 
> 
>> On 2014/6/26, 16:18, Corey Shalanski wrote:
>> We considered the necessity to shut down individual inverters and determined
that the added costs of an inverter output combiner panel were not merited. I
agree that in theory it seems beneficial to be able to switch each inverter
individually, but how often does this occur in practice? For the relatively
infrequent cases where we need to return to a jobsite and shut down an inverter
- for troubleshooting/removal/etc. - we do not mind shutting down the other
inverters (up to a limit) for what is hopefully a short period of time.
>> 
>> Again, this whole line of reasoning may be shown to be faulty if someone can
directly point to the Code section that requires OCPD on each individual
inverter.
>> 
>> --
>> Corey
>> $E1eB
>> 
>> 
>>> On Thu, Jun 26, 2014 at 9:20 AM, <re-wrenches-request@lists.re-wrenches.org>
wrote:
>>> 
>>> Message: 5
>>> Date: Wed, 25 Jun 2014 19:17:57 -0700
>>> From: William Miller <william@millersolar.com>
>>> To: RE-wrenches <re-wrenches@lists.re-wrenches.org>
>>> Subject: Re: [RE-wrenches] Combining Multiple Inverters
>>> Message-ID: <04F4B8FD-E280-4BF2-B5A4-C2FCA8D1C7A6@millersolar.com>
>>> Content-Type: text/plain; charset="utf-8"
>>> 
>>> Not allowed. You need a dedicated OCPD. Plus seems like a really bad idea. 
How do you shut down just one inverter?
>>> 
>>> 
>>> 
>>> Miller Solar
--- end of quote ---

