480.7 is Disconnect Methods, and addresses different scenarios and voltages (A) is for batteries "with a voltage over 60 volts dc" requiring a disconnect accessible to and within sight of the battery (B) is in regards to 1- and 2-family dwellings, and doesn't specify a voltage, just that an external, emergency disconnect is required (C) is segmenting strings into 240 Vdc nominal or less segments, and on it goes to (G)
I don't agree with the earlier statement in this chain (and I didn't dig up the original thread to see it in context) - based on how the Section is arranged; if the 60 volt requirement applied to both (A) and (B) then they would most likely be (A)(1) and (A)(2), under an (A) heading that included a statement to the effect of "For stationary storage batteries of 60 volts blah blah the following shall apply." As it is now, the emergency disconnect requirement (B) doesn't specify a voltage above which it applies, and the voltage specification in (A) doesn't apply to (B). Cheers, Brian Mehalic NABCEP Certified Solar PV Installation Professional™ R031508-59 National Electrical Code® CMP-4 Member (520) 204-6639 Solar Energy International http://www.solarenergy.org On Mon, Feb 20, 2023 at 11:40 AM James Jarvis via RE-wrenches < re-wrenches@lists.re-wrenches.org> wrote: > Did they ever explain why they were requiring it on a nominal 48 volt > system? NEC 480.7(B) (from memory, I think that is the right article) says > it is for nominal voltage of 60 volts or higher. IE your 48 volt system is > exempt. > > Jay pointed this out on February 3rd. > > > -James Jefferson Jarvis > APRS World, LLC > +1-507-454-2727 > http://www.aprsworld.com/ > > > On Mon, Feb 20, 2023 at 12:36 PM William Miller via RE-wrenches < > re-wrenches@lists.re-wrenches.org> wrote: > >> Friends: >> >> >> >> Here is how this resolved for my upcoming project: I submitted a request >> to the building department to waive the requirement for a DC disconnect. I >> based the justification on the need to keep a pressure pump for the fire >> sprinklers and a fire alarm operational. I will supply an external AC >> disconnect to de-energize all premise wiring except those circuits >> mentioned above. The request was granted. >> >> >> >> William >> >> >> >> Miller Solar >> >> 17395 Oak Road, Atascadero, CA 93422 >> >> 805-438-5600 >> >> www.millersolar.com >> >> CA Lic. 773985 >> >> >> >> >> _______________________________________________ >> List sponsored by Redwood Alliance >> >> Pay optional member dues here: http://re-wrenches.org >> >> 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 >> >> There are two list archives for searching. When one doesn't work, try the >> other: >> https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/ >> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org >> >> List rules & etiquette: >> http://www.re-wrenches.org/etiquette.htm >> >> Check out or update participant bios: >> http://www.members.re-wrenches.org >> >> _______________________________________________ > List sponsored by Redwood Alliance > > Pay optional member dues here: http://re-wrenches.org > > 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 > > There are two list archives for searching. When one doesn't work, try the > other: > https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/ > http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org > > List rules & etiquette: > http://www.re-wrenches.org/etiquette.htm > > Check out or update participant bios: > http://www.members.re-wrenches.org > >
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