To paraphrase: If PV circuits are located on or in any structure RSS is required. Exception: if the structure’s sole purpose is to house solar equipment then RSS is not required.
If your inverter is in a shed and there is one rake in that shed, RSS is required. William Miller Miller Solar.com 805-438-5600 www.millersolar.com On Wed, Nov 19, 2025 at 7:50 AM Zeke Yewdall via RE-wrenches < [email protected]> wrote: > You mention doing RSS on ground mounted PV arrays. This seems completely > not required by the code. From my reading of 690.12, module level remote > controlled rapid shutdown is only required on inhabited structures -- ones > that may involve roof operations of the fire department for ventilation. > Even detached garages with no occupancy do not appear to require it. If we > are just talking about the conductors coming off of the array going into a > home, it seems to me (and my inspectors have always agreed.. not initially, > but after I discussed it with them) that a switch mounted on the > groundmount array or where the underground conduit came up to go into the > building would suffice. > > Zeke > > On Tue, Nov 18, 2025 at 10:10 PM William Miller <[email protected]> > wrote: > >> Zeke: >> >> >> >> When this subject came up one of the wrenches replied to me off-list and >> shared photos of an Alps RSD that had burned up. He said tech support was >> of little help. >> >> >> >> Since then I have heard similar stories about Tigo products. >> >> >> >> I think the problem is trying to interrupt high voltage / high current PV >> DC under load. To do this with a mechanical switch you would see large >> blades surrounded by arc chutes, plastic shields and a metal can. Doing >> this switching in a small plastic nodule seems impractical. >> >> >> >> I am the last one to discount safety equipment--electrical fires kill a >> lot of people. However I am convinced that the RSS requirement preceded >> the availability equipment to implement the requirement and that gap has >> not closed. Now with UL3471 diluting the seriousness of hazard levels, RSS >> seems even more ludicrous. It is especially onerous to require module >> level RSS on ground mount arrays. >> >> >> >> Even more galling is the inability to complete a job I am in the middle >> of because there is apparently a nationwide shortage of RSDs. >> >> >> >> 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: [email protected] > > 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/[email protected]/ > 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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