Thanks August. I couldn't get the attachment to open, but I see what you're saying. You do bring up a good point about the AHJ as well. Few here have seen solar, and fewer are familiar with 690 so anything out of the ordinary usually gets flagged.
As Jeremy points out the 2011 NEC would allow this as a load side connection, so maybe I should spend my energy trying to convince them to let us follow the current Code instead. Thanks much, Garrison From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of August Goers Sent: Wednesday, February 27, 2013 3:43 PM To: RE-wrenches Subject: Re: [RE-wrenches] Conductor Sizing for Supply Side Connection Hi Garrison, In my opinion you only need to size the conductors to the overcurrent protection. Bill Brooks addressed a similar question of mine a few months ago - I've attached the email here. If you do a node analysis (ie see what would happen under both normal operation and fault conditions at any given point) you'll see that the current at any given point along the wire path will never exceed the breaker ratings on either side (or the higher of the two if they're different). It is a different story from what the 120% rule is addressing - in that case the current feeding into a busbar has the potential of being supplied by both the main breaker and the solar breaker thus potentially exceeding the bus capacity. I've used insulation piercing connectors from Burndy and Ilso with good results. Ilsco is called KUP-L-TAP and part number IPC-4/0-2/0 is a common one. You'll need to find the part number that best matches your wire size. It's a bit of a separate issue, but I've found that many jurisdictions are very critical of supply side connections and can start to ask questions about whether the whole setup is listed for the purpose. It is nearly impossible to get the manufacturer to list the entire service and line tap in my experience. You might want to look into that if you think your jurisdiction might have similar concerns. Good luck! Best, August August Goers Luminalt Energy Corporation 1320 Potrero Avenue San Francisco, CA 94110 m: 415.559.1525 o: 415.641.4000 aug...@luminalt.com From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Garrison Riegel Sent: Wednesday, February 27, 2013 1:15 PM To: 'RE-wrenches' Subject: [RE-wrenches] Conductor Sizing for Supply Side Connection Wrenches, On an upcoming job we have a Xantrex XW4548 interconnecting with a 200A service, and I'd very much appreciate some advice if y'all are willing. Since the inverter output OCPD is required to be 60A we are looking at a supply side connection, and I have two questions: 1. Before the point of interconnection the inverter output circuit will first pass through the XW Power Distribution Panel and inverter bypass, which is essentially a 60A breaker. The service disconnect for the supply side connection will also be fused at 60A. Does the 120% rule apply to the conductor between these two OCPDs? Or since this is a supply side connection in accordance with 690.64(A), 690.64(B)(2) will not apply? [this AHJ is on the 2008 NEC] 2. Can anyone recommend a reliable insulation piercing tap connector? Or would you recommend something else entirely for a residential supply side connection? Thanks in advance, Garrison 847-677-0950 Solar Service Inc.
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