[RE-wrenches] DC positive and negative in same conduit, other inspection issues

[Dave Click]

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?
> 
> 
>  
> 
> 
> 
> _______________________________________________
> List sponsored by Home Power magazine
> 
> List Address: RE-wrenches at lists.re-wrenches.org
> 
> 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:
> www.re-wrenches.org/etiquette.htm
> 
> Check out participant bios:
> www.members.re-wrenches.org
> 
>