Oh brother, that 230.72(A) is a nightmare. TVA and their 160 distributors are in the process of going to a line side feed in tariff from a load side production credit. Actually they plan on letting the distributor offer either or both options at their discretion. I'm laying out a job today with a standalone rack mounted 100 amp 3 phase 480 volt disconnect and feed thru meter out by the padmount transformer. The existing service is 2500 amp and because the service was installed under the building slab (new building) there is no outdoor disconnect. This means we would have to dig up a 2500 amp service and turn it up out by the padmount transformer. FORGET IT! That's a huge switch with 4 four inch conduits full of 400 MCM going in and going out of that switch.
This is onerous. Onerous I tell you! I would submit that the exception to 230.72 (A) for water pumps be amended to add clean renewable PV systems. John Wiles are you out there? Steve Johnson LightWave Solar Electric Nashville, TN From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of David Brearley Sent: Tuesday, March 10, 2009 12:28 PM To: RE-wrenches Subject: Re: [RE-wrenches] Line Side Feed In and Disconnects Wayne, As you suggested, because this is a new service, a PV service disconnect is required. The question of whether a second disconnect is required, a new disconnect for the main service, is a Code issue, as far as I can tell. It is also an interpretation, but I'll get to that later. It just so happens that the June/July issue of SolarPro magazine will have an extensive article on making PV interconnections. The authors are Ryan LeBlanc and Tarn Yates from SPG Solar. From their article, here are some Code articles that apply to selecting and locating a disconnect for a line side connection: 230.66 - Disconnect shall be listed for use as service equipment. 230.70(A)(1) - Disconnect shall be installed at a readily accessible location. 230.72(A) - All service disconnects shall be grouped together. The last article is no doubt the one that the AHJ is referencing in this case. The reason I feel that this extra expense and effort is an interpretation, as much as it is a Code issue, is that you could make a load side connection and still have the math work for the feed-in tariff program and for the revenue metering. How is that? Well, a meter on the inverter output circuits will read the total PV kWh for the feed-in tariff. A bi-directional meter for the revenue meter will read in-flow from the utility and out-flows to the utility. The difference between total PV kWh and the out-flow-kWh are the PV generated kWh that the customer used on site rather than export to the utility. Right? Whatever PV generated energy is not exported to the utility is used on site. So for billing purposes the customer is charged as follows: Total kWh for billing = In-flow kWh + (feed-in tariff kWh - out-flow kWh) Theoretically, this can also be implemented affordably by the utility: move the exiting revenue meter to the PV system; add a $100 bi-directional meter to the original meter can. Finished. Making a line-side connection is often difficult and expensive, especially when you now have to add a new service disconnect for the facility. At least in theory, it is also dangerous; the fault-currents there are higher. You have these implementation issues on the one hand. On the other hand you have a spreadsheet, or a one-time fix the the utility's billing software. So I think the utility is making this more onerous than they need to. Especially for small generators, the cost of this service upgrade will kill the deal. The utility probably isn't interested in this solution, but we can still dream of the perfect fix. David Brearley, Technical Editor SolarPro magazine NABCEP Certified PV Installer (tm) david.brear...@solarprofessional.com Direct: 541.261.6545 Fax: 541.512.0343 Visit our Web site at solarprofessional.com On 3/9/09 5:25 PM, "Allan Sindelar" <al...@positiveenergysolar.com> wrote: Wayne, Use this as a tool: http://www.solarabcs.org/utilitydisconnect/ and this: http://www.nrel.gov/docs/fy08osti/42675.pdf Allan Sindelar allan(at)positiveenergysolar.com <mailto:al...@positiveenergysolar.com><mailto:al...@positiveenergysolar.com> NABCEP Certified Solar PV Installer Positive Energy, Inc. 3201 Calle Marie Santa Fe NM 87507 505 424-1112 www.positiveenergysolar.com Please consider the environment before printing this e-mail. -----Original Message----- From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Wayne Irwin Sent: Monday, March 09, 2009 4:41 PM To: re-wrenches@lists.re-wrenches.org Subject: [RE-wrenches] Line Side Feed In and Disconnects Hello Wrenches, Here in Gainesville, Fla. we have recently adopted a Feed In Tariff. So, now we are supposed to directly feed the line side of the utility meter (essentially a new service). No big deal. As usual we use an AC disco between the inverter and the grid. However, the permit department is requiring that we install and additional disco between the existing service feed and the distribution panel to group all disco's in the same location. This especially adds an additional expense when dealing with 3 phase systems as well as the raises the question, is this really the National Electrical Code or just an interpretation? Your thoughts? Wayne Irwin, President Pure Energy Solar International Inc. Lic # CVC56695 <mailto:pureenergyso...@hotmail.com><mailto:pureenergyso...@hotmail.com> ________________________________ Date: Mon, 9 Mar 2009 18:20:57 -0400 From: reelli...@gmail.com To: re-wrenches@lists.re-wrenches.org Subject: Re: [RE-wrenches] Small Torque Wrench I got mine from "the knife and tool store" http://myworld.ebay.com/don19470/ on E bay. nice tool, adjustable 10 - 50 In Oz and he has others, just get the adapter that lets you use 1/4" drive bits and your good to go. It is a german tool and i use it on all breaker connections as well as others. Later, Bob On Mon, Mar 9, 2009 at 12:10 PM, Peter Parrish <peter.parr...@calsolareng.com> wrote: We have a great torque wrench for snugging down module clamps, Sharp SRS bolts, etc. What do folks use to insure that wire terminals are torqued to spec? We're talking 1.1 to 3.3 N-m (10-30 in-lbs). I'm imagining something compact like an over-sized screwdriver. - Peter Peter T. Parrish, President California Solar Engineering, Inc. 820 Cynthia Ave., Los Angeles, CA 90065 Ph 323-258-8883, Mobile 323-839-6108, Fax 323-258-8885 CA Lic. 854779, NABCEP Cert. 031806-26 peter.parr...@calsolareng.com _______________________________________________ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org 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 <http://www.re-wrenches.org/etiquette.htm><http://www.re-wrenches.org/etiquette.htm> Check out participant bios: www.members.re-wrenches.org <http://www.members.re-wrenches.org/><http://www.members.re-wrenches.org/> ________________________________ Windows Live(tm) Groups: Create an online spot for your favorite groups to meet. 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