[RE-wrenches] A related question - Individual AC conductors through separate conduits

Wed Nov 20 09:44:20 PST 2013

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] *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
NABCEP Certified PV Installation Professional
NABCEP Certified Technical Sales Professional
New Mexico EE98J Journeyman Electrician
Founder, *Positive Energy, Inc.*

A Certified B CorporationTM
3209 Richards Lane
Santa Fe, New Mexico 87507
*505 424-1112 office 780-2738 cell*
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

*From:* 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<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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