Thanks for the reply August. I’m working to get in touch with the engineer so we’ll see what they say.
I agree balancing the tap on all parallel conductors sounds like it would avoid the possibility of any issue, but I can’t think of what the problem would be if current from the grid were decreased on one or two conductors of a set. Any physicists out there have any opinions? A while back a reputable metering company told me I could put a single CT on one of six conductors from each set on a 2,000A service to get “revenue grade” meter data. I wasn’t sure they we right so I measured current on various conductors on each phase using multiple meters and saw significant deviations in on each conductor. I’m guessing differences in conductor length, terminal torque, bending radius, etc may have been an influence, but honestly not sure. If this is normal then maybe tapping only one or two conductors is not an issue? Coincidentally we are installing an 11.4kW inverter on a home (mansion) with a 1200A service (massive geothermal system) and a whole house generator. Luckily there is an extra lug in the ATS where we can land the inverter output on the line side, but if we did not have this lug the idea of splitting the 60A circuit across three conductors seems a little silly. Tap one #12 per 500MCM :)? Logically I see reason for possible concern on the commercial system, but with a smaller inverter it seems almost ridiculous...but if it’s fine for a small system then what’s the threshold? Thanks for any and all thoughts on this. Garrison > On Aug 21, 2018, at 11:02 AM, August Goers <aug...@luminalt.com> wrote: > > Hi Garrison, > > This is a new one for me - normally we always balance everything when dealing > with paralleled conductors. NEC 310.10(H) talks about conductors in parallel > and I can't see anything the explicitly forbids what you explained. To be > safe, I think it is worth contacting the PE to double check that they were > aware that there are three sets of parallel conductors on each phase. > > August > Luminalt > > >> On Tue, Aug 21, 2018 at 8:09 AM Garrison <garrison....@gmail.com> wrote: >> Hi Wrenches, >> >> When making a supply side connection on parallel sets of conductors is it >> required to tap all conductors on each phase? >> >> I have a set of plans with an 800A interconnection on a 1200A service. >> Service has three parallel sets of 500MCM. Plans call for tapping just two >> conductors on each set of three. Plans are stamped by an EE. I had been >> working under the assumption that if tapping parallel sets all conductors >> must be tapped. >> >> Any issues with not tapping all sets? >> >> Thanks, >> >> Garrison Riegel >> Rethink Electric >> 630-998-3629 >> _______________________________________________ >> 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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