[RE-wrenches] Conduit Bushings

Tue Mar 7 11:50:32 PST 2017

If I understood Peter’s original email properly, he noted that the ground
bushings had been “broken” to facilitate installation. If indeed regular
ground bushings had been modified or cut then that would violate the
correct installation methods. Here is a regular ground bushing:

If they actually installed the split-type retrofit style bushings, such as
the one below, then there shouldn’t be a problem:

I would cite NEC 250.97 Bonding for Over 250 Volts (4) Listed fittings. A
listed fitting must be used to bond the metal raceway. A modified or broken
ground bushing is not a listed fitting.

August

August Goers

Principal

Luminalt

m: 415.559.1525

o: 415.640.4000

august at luminalt.com

*From:* RE-wrenches [mailto:re-wrenches-bounces at lists.re-wrenches.org] *On
Behalf Of *Kirk Herander
*Sent:* Tuesday, March 07, 2017 10:58 AM
*To:* 'RE-wrenches'
*Subject:* Re: [RE-wrenches] Conduit Bushings

Peter,

Bridgeport makes both split ring grounding bushings and plastic bushings in
that size. No threading on to the connector required.

*From:* RE-wrenches [mailto:re-wrenches-bounces at lists.re-wrenches.org
<re-wrenches-bounces at lists.re-wrenches.org>] *On Behalf Of *William Miller
*Sent:* Saturday, March 04, 2017 3:08 AM
*To:* RE-wrenches
*Subject:* Re: [RE-wrenches] Conduit Bushings

Peter:

Would these work?

http://www.garvinindustries.com/conduit-fittings-supports/rigid-conduit-fittings/split-grounding-bushings/sgb50?gclid=CI7R876yvNICFQmIfgodVAkI3g

William

On Mar 3, 2017, at 11:14 AM, <peter.parrish at calsolareng.com> <
peter.parrish at calsolareng.com> wrote:

Recently we were asked to do a combined inspection and engineering review
of a 362.70 kWdc PV system using 5 Sungrow SG60KM-U inverters. We found
issues like palm trees and air handling equipment shading significant parts
of the arrays, electrician’s tape and palm fronds on the surface of the
modules. But we also observed two significant Code violations: PV  source
conductors lying on the surface of the torch-down roof and lack of bushings
at the connectors on the ends of 2” LFMC. The PV source conductors got
secured and we saw bushings threaded onto the ends LFMC connectors.

Upon close inspection we discovered that the bushings had been broken at
one point on their circumference, no doubt to simplify their attachment.
Their were 11 PV source circuits (22 current-carrying 10 AWG PV Wire
conductors.)

Is this a NEC Code violation? If so, what section would we cite? It seems
obvious that the bushing had been “modified”, but I would like to be more
specific. Or does it come under the workmanship category?

Regards,

   - Peter Parrish

Peter T. Parrish, Ph.D., President

SolarGnosis

1107 Fair Oaks Ave.

Suite 351

South Pasadena, CA 91030

(323) 839-6108

Peter.parrish at solargnosis.com

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