Keith:
No matter how you slice it, every breaker panel and every conductor in the
feeder from the inverter to the meter must meet the 120% rule. You can not
dedicate one panel as an "AC Combiner" and exceed the 120% rating on that
panel only. It does not matter if the source is one inverter or 10
inverters. You either meet the 120% requirement from section (B) or you
supply a supply side tap as allowed in (A).
William Miller
At 02:40 PM 2/9/2009, you wrote:
Hello
With the growth of the solar industry coupled with the generous incentives
now offered on fed part of the equation, we are seeing some trends here
and wondering what the approach has been in other areas. What kind of
feedback are you receiving from the AHJ?
There are some integrators who now are installing "systems" meaning,
multiple small inverters that are married to smaller arrays as opposed to
one large array with one large inverter.
So, it is quite conceivable to have, for example, 3- 3000 W SMA inverters
on a customers home. So, the point of connection issues arise. When you
look at 690.64B, it speaks to the 120% of the busbar rating.
What are folks doing in other areas, for this above example to address the
mechanical/electrical challenges associated with this situation, when if
you had 1- 200 amp residential service? There is alot of discussion, like
installing a 125 amp rated subpanel; interuppting the feeder from the
electric service and installing a 225 amp panel with a higher rated buss
(hard to find or custom made thru Cutler Hammer or others) etc.
We can also see a trend using the enphase products as well, but not as
much pronounced. It could be conceivable for a client to want to build
their system up over a few years and have 15, 175 watt panels on a circuit
(2P15 amp) and grow the system up to lets say, 45, 175 watt panels (3-2P15
amp). Same situation, different inverter manufacturer. My sense is this
trend will continue for the forseeable future, and alot of wrenches will
find orphaned systems out there and we should look at ways to address
point of connection issues that are bound to present themselves.
Thanks
Keith
Please note new e-mail address and domain:
William Miller
Miller Solar
Voice :805-438-5600 Fax: 805-438-4607
email: will...@millersolar.com
http://millersolar.com
License No. C-10-773985
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