[RE-wrenches] Solar accumulation panel

[Drake Chamberlin]

Here is a wild idea.  If you  look at the Enphase inverter systems, 
several inverters connect together in parallel before going to an 
overcurrent device.

In all cases, the point of connection to a utility system must be at 
a dedicated breaker.  If there were multiple string inverters that 
would connect to one breaker, why not just use a junction box, 
instead of a combiner panel?  You could put in an AC disconnect for 
each inverter, if it didn't come with one.

The wiring would need to be sized for the combined output of the 
multiple inverters, which in many cases wouldn't be an issue.

Drake



At 12:36 AM 1/13/2010, you wrote:
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>Andrew,
>
>It does not exist. We tried like crazy to get it into the 2011 NEC, 
>but to no avail. At the last second the proposal was put on hold 
>until the 2014 NEC. Major bummer. For now it can only be done with 
>AHJ approval. Many allow it but it is not in the NEC. Alternatively 
>you must use the sum of supply breakers no greater than 120%. Much 
>more restrictive.
>
>Bill.
>
>From: re-wrenches-bounces at lists.re-wrenches.org 
>[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Andrew Truitt
>Sent: Tuesday, January 12, 2010 10:57 AM
>To: RE-wrenches
>Subject: [RE-wrenches] Solar accumulation panel
>
>
>Team wrenches - I feel like I've seen a provision in the Code for 
>installing a sub-panel to aggregate PV inverter outputs for the 
>purpose of simplifying the actual grid connection (such as for a 
>line-side tap) but I can't find it in 690.  I also seem to remember 
>specific verbiage that needs to be on the panel along the lines of 
>"PV circuits only.  Do not add load breakers." to ensure compliance 
>with 690.64(B).  Does anyone know where I can find this info in the NEC?
>
>
>Andrew Truitt
>Standard Solar Inc.
>
>
>--
>"Don't get me wrong: I love nuclear energy! It's just that I prefer 
>fusion to fission. And it just so happens that there's an enormous 
>fusion reactor safely banked a few million miles from us. It 
>delivers more than we could ever use in just about 8 minutes. And 
>it's wireless!"
>
>~William McDonough
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Drake Chamberlin
Athens Electric
OH License 44810
CO License 3773
NABCEP TM  Certified PV Installer
Office - 740-448-7328
Mobile - 740-856-9648  
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