[RE-wrenches] ballasted roof rack - on the ground?
Dave Click
daveclick at fsec.ucf.edu
Sat Aug 22 16:25:42 PDT 2009
I think that the 250kW Florida Power & Light array in Sarasota, FL was
installed on a ground cover (over a landfill) like the SIT solution, and
that it was just done with PowerGuard.
-------- Original Message --------
Subject: Re: [RE-wrenches] ballasted roof rack - on the ground?
From: Joel Davidson <joel.davidson at sbcglobal.net>
To: RE-wrenches <re-wrenches at lists.re-wrenches.org>
Date: 2009/8/21 10:14
> Geoff,
>
> Solar Integrated Technologies adheres its panels on ground covers
> over landfills to capture landfill gases and separately produce PV
> electricity. Perhaps a wrench with Powerlight experience can tell us why
> rigid modules are not laid on a ground cover.
>
> Joel Davidson
>
> ----- Original Message -----
> *From:* Geoff Greenfield <mailto:geoff at third-sun.com>
> *To:* RE-wrenches <mailto:re-wrenches at lists.re-wrenches.org>
> *Sent:* Thursday, August 20, 2009 8:35 PM
> *Subject:* [RE-wrenches] ballasted roof rack - on the ground?
>
> esteemed wrenches (or just steamed if youve been out in the hot lately)
>
> I'm curious why more folks don't use the same flat roof ballasted
> rack approach for large ground mounts? Geotech weed barier and off
> we go... my initial calcs sat its a cost saver... my instinct says
> it viable, but my other instinct says "if it were this easy I would
> see it all the time (and I've never seen it)
>
> what's up? frost heave/instability? wav-i-ness of the ground?
> better performance at steep angle worth all the extra cost (not
> according to my pencil with today's mod costs). Thoughts?
>
> 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
> www.Third-Sun.com
>
> Clean Energy - Expertly Installed
>
>
>
>
>
>
> ----- "Dave Click" <daveclick at fsec.ucf.edu> wrote:
> > Thanks all.
> >
> > It was my understanding that we should still be running the
> conductors
> > of the same circuit through the same raceway, even if it is the
> DC input
> > into the inverter since that DC oscillates slightly (nowhere near as
> > much as AC). I wasn't concerned about eddy currents in the FNMC of
> > course but the metal box itself, a concern being voiced on this list
> > before. I'd be more concerned about this if it were a 1MW inverter
> > rather than a 7kW, but still.
> >
> > Thanks for the info on the GEC tap and I'm glad the split bolts
> work here.
> >
> > The conduit in question doesn't seem to be there just for physical
> > protection; the wire runs from the east end of the array for
> 100'+ and
> > only the last 3' are in conduit. If it were only for protection
> I'd be
> > fine with it being open-ended on both ends, but since it's there
> to feed
> > the conductors into the box, that's why I was treating it as a
> regular
> > conduit that required a cord grip at the other end. Where do
> others make
> > the distinction?
> >
> > Thanks,
> > DKC
> >
> > -------- Original Message --------
> > Subject: Re: [RE-wrenches] DC positive and negative in same conduit,
> > other inspection issues
> > From: Kelly Keilwitz, Whidbey Sun & Wind <kelly at whidbeysunwind.com>
> > To: RE Wrenches listserve <re-wrenches at lists.re-wrenches.org>
> > Date: 2009/8/19 21:10
> >
> > > Dave,
> > > Only GEC's are subject to the "continuous" rule (250.64C). It
> sounds like
> > > your are talking about an EGC tapped from the GEC.
> > >
> > > When splicing PV GEC's required under 690.47D, either together
> (from
> > > separated arrays) or to the existing AC GEC (if close enough),
> we have been
> > > allowed to use split bolts instead of irreversible splices, per
> 250.64D1,
> > > "Grounding Electrode Conductor Taps" (at end of paragraph).
> I.E., the
> > > "continuous" rule is only being applied to the main GEC.
> > >
> > > I agree with Kurt on the LTNMF being used only as extra (not
> required) wire
> > > protection for the USE-2. We often do this when running PV
> conductors
> > > between short separations in modules or rails. I would think
> that only
> > > temperature and fill corrections would apply - and only if the
> length
> > > requires.
> > >
> > > -Kelly
> > >
> > > Kelly Keilwitz, P.E.
> > > Whidbey Sun & Wind, LLC
> > > Renewable Energy Systems
> > > NABCEP Certified PV Installer
> > > 987 Wanamaker Rd,
> > > Coupeville, WA 98239
> > > PH & FAX 360-678-7131
> > > sunwind at whidbeysunwind.com
> > >
> > > On 8/19/09 2:41 PM, "Dave Click" <daveclick at fsec.ucf.edu> wrote:
> > >
> > >> For the grounding electrode wiring, it seems that it's fine to
> me since
> > >> they ran the continuous #6 to each rail and then to the rod,
> qualifying
> > >> as the 690.47(D) supplemental electrode. But the split bolts
> tapping
> > >> that GEC to "ground the disconnect," these are required to be
> > >> irreversible connections to the ground bus in that disconnect,
> right?
> > >
> > >
> > >
> > >
> > >
> > >
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