August,
Yes, that's relevant to my question. All metal boxes are grounded
at both ends by existing EGCs. Only the PVC conduit is not. So
when I read section 250.110 as you have cited, " all
equipment fastened in place with exposed non-current carrying
metal parts likely to become energized needs equipment grounding"
is covered correctly.
This is not a huge deal - it's not difficult to pull the #4 out
and add an EGC. I'm just trying to find the appropriate Code
reference for an oddball situation. Thank you.
Allan
Allan Sindelar
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 CorporationTM
3209
Richards Lane
Santa Fe, New Mexico 87507
505 424-1112 office 780-2738 cell
www.positiveenergysolar.com
On 11/20/2013 10:44 AM, August Goers wrote:
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
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
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
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
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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