[RE-wrenches] Point of connection

[William Miller]

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: william at millersolar.com
http://millersolar.com
License No. C-10-773985
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