[RE-wrenches] A related question - Individual AC conductors through separate conduits
Ray Walters
ray at solarray.com
Wed Nov 20 13:21:14 PST 2013
My take on 250.110, is that you could run separate EGCs from either end
to bond the metal J boxes, and not have the EGC run the entire length
through the PVC.
Option 2: attach a Bobcat to one end of the PVC and rip it out of the
ground, then use the freshly made trench to reinstall what the
inspectors want to see (larger conduit with 2 conductors). Ugh....
R.Ray Walters
CTO, Solarray, Inc
Nabcep Certified PV Installer,
Licensed Master Electrician
Solar Design Engineer
303 505-8760
On 11/20/2013 10:44 AM, August Goers wrote:
> National Electrical Code 2008 Edition
>
> Hi Allan,
>
> Per NEC 250.110 all equipment fastened in place with exposed
> non-current carrying metal parts likely to become energized needs
> equipment grounding. There are some conditions and exceptions listed
> in the code so you might want to check through that section and apply
> it to your situation. If you had used metallic conduit such as EMT
> then the raceway itself would count for equipment ground. However,
> since it sounds like you have non-metallic conduit you do indeed need
> a equipment ground wire sized per table 250.122. My general rule of
> thumb is that all metal boxes and raceways need equipment ground,
> period. We run equipment ground conductors even in EMT because there
> is a chance that fittings will loosen over time.
>
> Anyway, that's my take.
>
> Best,
>
> August
>
> *From:*re-wrenches-bounces at lists.re-wrenches.org
> <mailto:re-wrenches-bounces at lists.re-wrenches.org>
> [mailto:re-wrenches-bounces at lists.re-wrenches.org
> <mailto:re-wrenches-bounces at lists.re-wrenches.org>] *On Behalf Of
> *Allan Sindelar
> *Sent:* Tuesday, November 19, 2013 3:34 PM
> *To:* RE-wrenches
> *Subject:* Re: [RE-wrenches] A related question - Individual AC
> conductors through separate conduits
>
> Wrenches,
> I need similar advice, please, especially a Code section citation.
>
> In 2005 we installed an Outback system for a new home in town that was
> designed and installed to be a grid-backup solar home. It was, in
> essence, a stand-alone system to run most of the home with the utility
> serving the backup generator's role, both to provide backup charging
> when needed and to run a few specific loads. The home was built with
> two breaker panels side by side, with the PV system wired between
> them. The meter pedestal was 150' away at the edge of the street. The
> array was small at 1.32 kW.
>
> Around 2007 the interconnection terms were quite good and we converted
> this system into a grid-intertied system. Doing this involved
> replacing the early Outback FX2024 with a GVFX3524. We also had to run
> an additional #4 conductor from the system (inverter AC interactive
> output) to the meter pedestal in order to carry interactive sell-back
> energy to a REC meter, which had to be located next to the revenue
> meter. We ran this single conductor in 1" PVC conduit with no other
> conductor. Given that all AC neutrals were properly bonded, that the
> conduit was non-conductive, and that all metal parts were properly
> bonded, we didn't run an EGC with this single THWN. We were permitted
> and and passed inspection.
>
> Now we are adding an additional 1.3 kW of PV to the system, which
> requires full permit process, of course. And in the ensuing years the
> home has been annexed into the city, with its reputation for toughness
> in regards to Code compliance. Our design team tells me that we must
> pull that #4 out and repull it with an EGC, simply because every
> current-carrying conductor must have a grounding conductor as well.
>
> My question: What Code section applies here? Is an EGC always required
> in conduit carrying a single current-carrying conductor?
>
> We're trying to have our ducks in a row before contacting the
> inspector, and have never dealt with this particular situation before.
> Thank you,
> Allan
>
> *Allan Sindelar*
> Allan at positiveenergysolar.com <mailto:Allan at positiveenergysolar.com>
> NABCEP Certified PV Installation Professional
> NABCEP Certified Technical Sales Professional
> New Mexico EE98J Journeyman Electrician
> Founder, *Positive Energy, Inc.*
>
> A Certified B Corporation^TM
> 3209 Richards Lane
> Santa Fe, New Mexico 87507
> *505 424-1112 office 780-2738 cell*
> www.positiveenergysolar.com <http://www.positiveenergysolar.com/>
>
> On 11/19/2013 11:22 AM, Dave Click wrote:
>
> *300.3(B) Conductors of the Same Circuit.* All conductors of the
> same circuit and, where used, the grounded conductor and all
> equipment grounding conductors and bonding conductors shall be
> contained within the same raceway, auxiliary gutter, cable tray,
> cablebus assembly, trench, cable, or cord, unless otherwise
> permitted in accordance with 300.3(B)(1) through (B)(4) [which
> don't help here].
>
> On 2013/11/19, 12:38, August Goers wrote:
>
> Hi All --
>
> On a related note, I've become good friends with some of the
> inspectors in San Francisco and they called me yesterday with
> a question. Is it okay to run _individual_ DC conductors
> through EMT for wire management purposes? We have always run
> paired positive and negative conductors in conduit so the
> question had never occurred to me. Obviously, you have to bond
> both ends of the conduit if it is over 250 v. I know that AC
> would have induction issues with running individual conductors
> but I'm not sure with DC.
>
> Thanks,
>
> August
>
> August Goers
>
> Principal
>
> Luminalt Energy Corporation
>
> o: 415.641.4000
>
> m: 415.559.1525
>
> www.luminalt.com <http://www.luminalt.com>
>
> *From:*re-wrenches-bounces at lists.re-wrenches.org
> <mailto:re-wrenches-bounces at lists.re-wrenches.org>
> [mailto:re-wrenches-bounces at lists.re-wrenches.org
> <mailto:re-wrenches-bounces at lists.re-wrenches.org>] *On Behalf
> Of *William Miller
> *Sent:* Monday, November 18, 2013 11:33 PM
> *To:* 'RE-wrenches'
> *Subject:* Re: [RE-wrenches] PV Wiring methods
>
> Bill:
>
> There is no need to stuff MC4 cables into standard conduit.
> You can either slot the pipe using our easy method or install
> bulkhead type connectors. The connectors are readily
> available. I get them from PV Cables in Northern California..
>
> Wire routing problems and some solutions can be found on our
> web-site:
>
> http://millersolar.com/MillerSolar/practices/PV_wiring/_PV_Wiring2.html
>
> Since the industry won't provide wire management solutions, we
> are making our own. Questions: Just write or call.
>
> William Miller
>
> *From:*re-wrenches-bounces at lists.re-wrenches.org
> <mailto:re-wrenches-bounces at lists.re-wrenches.org>
> [mailto:re-wrenches-bounces at lists.re-wrenches.org] *On Behalf
> Of *frenergy
> *Sent:* Thursday, November 14, 2013 7:46 AM
> *To:* RE-wrenches
> *Subject:* Re: [RE-wrenches] PV Wiring methods
>
> William, Bill....from another Bill,
>
> Two things: For the rest of us (maybe it's just me?!)
> that's still trying to figure out how (or why) to stuff a MC4
> connector into conduit and my hesitation in using SS wire ties
> for fear of the sharp edges cutting or chaffing into cables,
> I'm open for advice. Any wire I use on the roof is rated for
> that type of service and I have some off-grid systems that
> have been in the sun for some 25 years where the wire still
> looks nearly new even when flexing it to look for
> checking/cracks. It seems the wire/insulation can take it,
> thus it seems like the key to "wire management is to keep the
> wire from moving and off the roof, secured to the racking,
> thus not compromising the insulation.
>
>
>
>
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