Bonding Bushing

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KRG9729

Member
Location
New York
Is it permissible to pick up an equipment ground by installing a bonding bushing on an EMT connector.
The conduit is being used as the equipment ground. However we have a combination plastic fixture frame with a metal ballast cover that needs to be grounded. The emt terminates to the plastic frame.
 

Jim1959

Senior Member
Location
Longmont, CO
Is it permissible to pick up an equipment ground by installing a bonding bushing on an EMT connector.
The conduit is being used as the equipment ground. However we have a combination plastic fixture frame with a metal ballast cover that needs to be grounded. The emt terminates to the plastic frame.

I believe this is appropriate.
 

iwire

Moderator
Staff member
Location
Massachusetts
Bob, got a code section?

Depending on the specifics of the OPs installation this may or may not apply


314.3 Nonmetallic Boxes. Nonmetallic boxes shall be permitted
only with open wiring on insulators, concealed knoband-
tube wiring, cabled wiring methods with entirely nonmetallic
sheaths, flexible cords, and nonmetallic raceways.

Exception No. 1: Where internal bonding means are provided
between all entries, nonmetallic boxes shall be permitted
to be used with metal raceways or metal-armored
cables.

Exception No. 2: Where integral bonding means with a
provision for attaching an equipment bonding jumper inside
the box are provided between all threaded entries in
nonmetallic boxes listed for the purpose, nonmetallic boxes
shall be permitted to be used with metal raceways or metalarmored
cables.
 

KRG9729

Member
Location
New York
Depending on the specifics of the OPs installation this may or may not apply

The installation involves changing metal fluorescent strip lights to vapor-tight fixtures. The feeds are in EMT. The vapor-tight fixture has a plastic housing. The conduit terminates to the plastic housing.
 

jaylectricity

Senior Member
Location
Massachusetts
Occupation
licensed journeyman electrician
Depending on the specifics of the OPs installation this may or may not apply

Exception No. 1: Where internal bonding means are provided
between all entries, nonmetallic boxes shall be permitted
to be used with metal raceways or metal-armored
cables.

So the single entry will be bonded. Seems ok to me.
 

jaylectricity

Senior Member
Location
Massachusetts
Occupation
licensed journeyman electrician
Or if it it's a pipe in/pipe out situation you'll need bonding bushings on both and they are to be bonded together along with the equipment ground.
 

Carultch

Senior Member
Location
Massachusetts
Is it permissible to pick up an equipment ground by installing a bonding bushing on an EMT connector.
The conduit is being used as the equipment ground. However we have a combination plastic fixture frame with a metal ballast cover that needs to be grounded. The emt terminates to the plastic frame.

That's precisely how you are supposed to do it. Establish electrical continuity to the conduit, with a bonding jumper, because the conduit cannot bond to the insulator box.

This chart applies when a wire EGC is present. When one isn't present, it needs electrical continuity on both ends, and across any discontinuity of metal.
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texie

Senior Member
Location
Fort Collins, Colorado
Occupation
Electrician, Contractor, Inspector
The installation involves changing metal fluorescent strip lights to vapor-tight fixtures. The feeds are in EMT. The vapor-tight fixture has a plastic housing. The conduit terminates to the plastic housing.

I used to lean toward the opinion that this was a violation of 314.3 because the language of Exception 1 seemed to imply that this needed to be part part of the box as manufactured. But just the other day I saw a new EMT connector from Bridgeport that has slightly longer threaded portion and is advertised to have extra length to allow for a lock nut and a bonding bushing when connecting to thick non-metallic enclosures. This would seem to imply that what you are doing is compliant and maybe I was misinterpreting Exception 1. In any case what you are proposing is commonly done. Seems safe to me.
 
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