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-boun...@lists.re-wrenches.org
<mailto:re-wrenches-boun...@lists.re-wrenches.org>
[mailto:re-wrenches-boun...@lists.re-wrenches.org
<mailto:re-wrenches-boun...@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*
al...@positiveenergysolar.com <mailto:al...@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-boun...@lists.re-wrenches.org
<mailto:re-wrenches-boun...@lists.re-wrenches.org>
[mailto:re-wrenches-boun...@lists.re-wrenches.org
<mailto:re-wrenches-boun...@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-boun...@lists.re-wrenches.org
<mailto:re-wrenches-boun...@lists.re-wrenches.org>
[mailto:re-wrenches-boun...@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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