You should always specify Sched 80 for those stubs out of the ground. Makes sense to me that an AHJ requires it -- protect the conductors from maintenance tractor, lawn mower, weed whip, show shovel (Minnesota), and temperature differentials (transitioning from underground temps to air). But I haven't ever seen a formal definition of "subject to physical damage" in the code. 230.5 describes a few examples of physical damage areas for protection (although is specifically talking about service entrance conductor locations) which includes exactly your conductor locations. Also review Articles 300.4 and 300.5.
> On September 13, 2017 at 3:02 PM Dana <[email protected]> wrote: > > > Same rule enforced here in Idaho & Colorado. In Idaho we even have to use > Sched 80 anywhere above the finished floor even the attic and in walls [if > required]. > > > > > ---------------------------------------------------------------------------- > > Dana Orzel Great Solar Works, Inc. > > 208.721.7003 [email protected] > > Idaho Contractor - # 028765 Idaho PV # 028374 > > NABCEP # 051112-136 www.solarwork.biz > > "Responsible Technologies for Responsible People since 1988" > > P Please consider the environment before printing this email. > > > > > > From: RE-wrenches [mailto:[email protected]] > On Behalf Of Jerry Caldwell > Sent: Wednesday, September 13, 2017 11:03 AM > To: RE-wrenches <[email protected]> > Subject: [RE-wrenches] definition of "areas of physical damage" > > > > Dear Wrenches, > > > > I have a residential ground mounted installation that did not pass > inspection due to schedule 40 PVC conduit stubbing up from a trench to the > inverters and subpanel. The inverters and subpanel are hung on Unistrut, > which is attached to the rear posts of the ground rack. There is a second > subpanel next to the main on the side of the house with schedule 40 stubbing > up into it as well. > > > > The inspector insists that conduit stubbing out of the ground is > subject to physical damage and needs to be replaced with schedule 80 even > though it is not in an area where vehicles or mobile equipment are used. Is > there a generally accepted definition of "areas of physical damage" as seen > in 350.10 (F)? > > > > The inspector has said he would consider my argument if I can provide > language from the Code to back up my position. > > > > Any help is greatly appreciated. > > Jerry Caldwell > > > > On Saturday, October 4, 2008 8:28 AM, Geoff Greenfield > <[email protected] mailto:[email protected] > wrote: > > > > thanks for input Bill, and also for tip on zipties. We have dealt > with intermittent groundfaults caused by faulty xlp! Had to spray water on > array to "find" it. PITA! Almost makes me want to submerge the spool next > time and do my own test. > > > > > > > > For a brighter energy future, > > > > Geoff Greenfield > > President > > Third Sun Solar & Wind Power Ltd. > > 340 West State Street, Unit 25 > > Athens, OH 45701 > > > > 740.597.3111 Fax 740.597.1548http://www.Third-Sun.com > > > > Clean Energy - Expertly Installed > > > > > > > > > > > > > > ----- Bill Brooks <[email protected] mailto:[email protected] > > wrote: > > > Geoff, > > > > > > SS zip ties are good, but you must be very careful not to pull them > tight. > > > They should only be snug, not tight. These SS zip ties have been > shown to > > > cause ground faults in many cases. Commercial rooftops are > accessible, but > > > not readily accessible. Conductors must be supported properly and > protected > > > from physical damage. The conductors must follow structural > members. If they > > > leave structural members, they must be in a raceway of some kind. A > variety > > > of options there. > > > > > > Bill. > > > > > > -----Original Message----- > > > From: [email protected] > mailto:[email protected] > > > [mailto:[email protected] > mailto:[email protected] ] On Behalf Of Geoff > > > Greenfield > > > Sent: Friday, October 03, 2008 7:19 AM > > > To: RE-wrenches > > > Cc: Randy; Kent Phillips > > > Subject: [RE-wrenches] Protection of Conductors > > > > > > Hey wrenchers... we have an internal debate going about a code > section > > > interpretation... "subject to physical damage". Code compliance is > a must, > > > best practice is an expectation (...weighed against material and > labor cost > > > (prevailing wage job)). > > > > > > Application is a flat roof with no public access (locked hatch). > We are > > > using DP+W "Power-tube" flat roofing system for the first time... > the > > > question is how to deal with the inter-row N-S wire runs... about > 100 gaps > > > about 24" between the E-W rows of panels. There are plenty of > 2"x2" strut > > > members running under the array N-S. We will "exit" the array field > in > > > ridgid conduit to combiner boxes. > > > > > > The flat roof system we usually use has built in wire trays... > using this > > > new system has brought up this question... Our options include > dressing the > > > XLP bundles with SS zip ties alongside the N-S struts, or using > Galv. RMC, > > > strapped, with bushings (or S-80 PVC) at all these walkways... or > using > > > Unistrut (w/cap) as a lay in wireway (to speed up labor > (debatable)). > > > > > > Below are some of the code references... the basic question seems > to be: > > > does the limited access of this roof keep us out of "subject to > physical > > > damage"? What is a "Readily accessible location?" > > > > > > Thanks everyone. > > > > > > For a brighter energy future, > > > > > > Geoff Greenfield > > > President > > > Third Sun Solar & Wind Power Ltd. > > > 340 West State Street, Unit 25 > > > Athens, OH 45701 > > > > > > 740.597.3111 Fax 740.597.1548 > > >http://www.Third-Sun.com > > > > > > Clean Energy - Expertly Installed > > > > > > > > > > > > > > Next, one might argue, I suppose, that the racking system itself, > acts > > > > as > > > > protection and that the conductors should therefore, not be > considered > > > > to > > > > be exposed. I disagree based on NEC definition. That stated, I > > > > would > > > > consider these NEC references for more perspective: > > > > > > > > Pretty straightforward NEC 100 Definitions Exposed (as applied to > > > > wiring > > > > methods): On or attached to the surface... > > > > > > > > NEC 300.4 gives various cases for protection against physical > damage > > > > requirements. Long article. Worth a read. Does not address our > > > > exact > > > > case, but I would say that the following methods would be > appropriate > > > > based on similar cases... > > > > > > > > NEC 344.10 (A)(1) Galvanized steel and stainless steel RMC. > ...shall > > > > be > > > > permitted under all atmospheric conditions and occupancies. > > > > > > > > NEC 352.10(f) Exposed. PVC conduit shall be permitted for exposed > > > > work. > > > > PVC conduit used exposed in areas of physical damage shall be > > > > identified > > > > for the use. FPN: PVC conduit, Type Schedule 80, is identified > for > > > > areas > > > > of physical damage. > > > > > > > > Also, > > > > > > > > NEC 690.31(A) ...Where photovoltaic source and output circuits > > > > operating > > > > at maximum system voltages greater than 30 volts are installed in > > > > readily > > > > accesible locations, circuit conductors shall be installed in a > > > > raceway. > > > > > > > > One might argue, then, why don't the module interconnects have to > be > > > > protected, also... > > > > > > > > NEC 690.31(B) is really the key to all of this: Single-Conductor > > > > Cable. > > > > Single-conductor cable type USE-2, and single-conductor cable > listed > > > > and > > > > labeled as photovoltaic (PV) wire shall be permitted in exposed > > > > outdoor > > > > locations in photovoltaic source circuits FOR PHOTOVOLTAIC MODULE > > > > INTERCONNECTIONS within the photovoltaic array. > > > > > > > > So, I suppose that if our source circuit interconnections extend > from > > > > row > > > > to row, then we can leave those exposed. I don't like it, but it > > > > would > > > > probably have to be accepted. > > > > > > > > > > > _______________________________________________ > > > List sponsored by Home Power magazine > > > > > > List Address: [email protected] > mailto:[email protected] > > > > > > 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: > > >http://www.re-wrenches.org/etiquette.htm > > > > > > Check out participant bios: > > >http://www.members.re-wrenches.org > > > > > > _______________________________________________ > > > List sponsored by Home Power magazine > > > > > > List Address: [email protected] > mailto:[email protected] > > > > > > 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: > > >http://www.re-wrenches.org/etiquette.htm > > > > > > Check out participant bios: > > >http://www.members.re-wrenches.org > > > > > > > _______________________________________________ > > List sponsored by Home Power magazine > > > > List Address: [email protected] > mailto:[email protected] > > > > 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:http://www.re-wrenches.org/etiquette.htm > > > > Check out participant bios:http://www.members.re-wrenches.org > > > > > > _______________________________________________ > List sponsored by Redwood Alliance > > List Address: [email protected] > > Change listserver email address & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > List-Archive: > http://www.mail-archive.com/[email protected]/maillist.html > > List rules & etiquette: > www.re-wrenches.org/etiquette.htm > > Check out or update participant bios: > www.members.re-wrenches.org > > Charlie Pickard NABCEP Certified PV Installer 952-567-4479 (cell) 952-401-7073 (office) [email protected] mailto:[email protected]
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