Anything less than a 100A main is a no-go a for residential service: NEC 230.79(C): "For a one-family dwelling, the service disconnecting means shall have a rating of not less than 100 amperes, 3-wire."
Also, I don't think any AHJ is going to accept a load calculation in lieu of proper bus sizing in the service. What's to stop the owner from adding loads later on? I agree with Eric... time for a service upgrade. -Hans Frederickson -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Steven Lawrence Sent: Wednesday, March 31, 2010 9:54 AM To: [email protected] Subject: Re: [RE-wrenches] Supply Side Tap Overcurrent Protection Why can't you do a line side tap and downsize the main breaker? Use a 60A main disconnect for the line side tap, and use a 60A main breaker for the service panel. That's similar to what I did except I downsized the 200A main to a 150A. This also allowed a manual interlock kit in the main service panel that can be fed from the backup load panel. Steven Lawrence ______________________________________________________ Date: Wed, 31 Mar 2010 08:13:10 -0700 (PDT) From: Nick Soleil <[email protected]> To: RE-wrenches <[email protected]> Subject: Re: [RE-wrenches] Supply Side Tap Overcurrent Protection Message-ID: <[email protected]> Content-Type: text/plain; charset="us-ascii" Downsize the main breaker? I would if I could, but the customer only has 100 Amps now, and the solar is fed with two breakers, a 30A and a 40A. So to be under 120Amps, I would have to size the main to 50 Amps, which may be problematic. I can also do the line side tap, but had heard that a load analysis may be accepted instead. The loads of the house will never use more than 100 Amps. I am wondering if any codes or white papers detail that option. Nick Soleil Project Manager Advanced Alternative Energy Solutions, LLC PO Box 657 Petaluma, CA 94953 Cell: 707-321-2937 Office: 707-789-9537 Fax: 707-769-9037 _______________________________________________ List sponsored by Home Power magazine List Address: [email protected] Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org _______________________________________________ List sponsored by Home Power magazine List Address: [email protected] Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
