I have worked out the area under the daily bell curve. A 2% loss at max current equals 1% loss average. Maybe this logic could allow some flexibility.
William > On Jul 25, 2015, at 5:52 AM, Jerry Shafer <jerrysgarag...@gmail.com> wrote: > > Wrenches > I have 3 engineering firms and one in-house engineer that only use 1% because > in the NEC it is stated as a suggestion and not a requirement but they take > this as a must not exceed instead, > I cant change CC as it will be remotely monitored via the Outback connection, > the Engineers refuse to make any changes to the 1% and still stamp the > drawings. This is what I have found in my research it came from Mike Holt > > Contrary to common belief, the NEC generally doesn't require you to size > conductors to accommodate voltage drop. It merely suggests in the Fine Print > Notes to 210.19(A), 215.2(A)(4), 230.31(C), and 310.15(A)(1) that you adjust > for voltage drop when sizing conductors. It's important for you to remember > that Fine Print Notes are recommendations, not requirements [90.5(C)]. > > The NEC recommends that the maximum combined voltage drop for both the feeder > and branch circuit shouldn't exceed 5%, and the maximum on the feeder or > branch circuit shouldn't exceed 3%. This recommendation is a performance > issue, not a safety issue. > > Jerry > > >> On Wed, Jul 22, 2015 at 11:28 AM, Starlight Solar Power Systems >> <la...@starlightsolar.com> wrote: >> Jerry, >> >> A long distance wire run is practical now days using a high voltage >> controller. Have a look at Schneider and Morningstar 600Vdc controllers. Not >> sure what you mean "by nothing can be changed but wire size” but you will >> have to rewire the strings into series and protect the wire run. >> >> Larry Crutcher >> Starlight Solar Power Systems >> >> >> >> On Jul 22, 2015, at 10:37 AM, Jerry Shafer <jerrysgarag...@gmail.com> wrote: >> >> Wrenches >> Some time back there was discussion on the conductor size and efficiency >> rating requirement for long DC runs. >> What I am looking at is this, 400 feet of MCM 400 to keep the line loss at >> or below 1% per NEC code for an off grid application, cost vs return is not >> acceptable. 2/0 is less than 2.5% and the cost is far less. Specs are 4 >> strings of 3, 250 watt modules feeding one Outback FM 80 charge controller. >> There are lots of things I can do like SMA instread, or 200 VDC charge >> controller but nothing can be changed except the wire gauge. Does anyone >> recall a thread with this topic. >> >> thoughts ?? >> Jerry >> ________________________ >> >> >> >> _______________________________________________ >> List sponsored by Redwood Alliance >> >> List Address: RE-wrenches@lists.re-wrenches.org >> >> Change listserver email address & settings: >> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org >> >> List-Archive: >> http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html >> >> List rules & etiquette: >> www.re-wrenches.org/etiquette.htm >> >> Check out or update participant bios: >> www.members.re-wrenches.org > > _______________________________________________ > List sponsored by Redwood Alliance > > List Address: RE-wrenches@lists.re-wrenches.org > > Change listserver email address & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > List-Archive: > http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html > > List rules & etiquette: > www.re-wrenches.org/etiquette.htm > > Check out or update participant bios: > www.members.re-wrenches.org >
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