Bonding; metallic conduit between CT/meter and service disconnect

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curious101

Senior Member
Location
Atlanta, GA, USA
Good morning,
Question regarding the attached partial one line for a commercial building. I highlighted the conductor between the CT/meter enclosure and the service disconnect. Question: if the highlighted conduit is metallic, do we have to provide a supply side bonding jumper from the CT/meter enclosure? I know, we don't have to if that conductor is non-metallic.

Thank you!
 

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texie

Senior Member
Location
Fort Collins, Colorado
Occupation
Electrician, Contractor, Inspector
The CT can and the nipple must be bonded per 250.92. There are a number of ways to do this. You could bond the neutral to the CT can and use bonding bushings on one end of the nipples with jumpers as one solution. Another way would be as implied in the drawing and use a jumper to bond one end of the nipples and also the CT can. I prefer CT cans with a factory bonding jumper so you only need to worry about bonding the nipples but there are many ways to to this. The bottom line is all metallic items on the line side must be bonded per 250.92, either by jumpers or simply connecting to the neutral.
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
A bonding locknut on one end of the metallic raceway will work also if there are no concentric or eccentric knockouts.
 

curious101

Senior Member
Location
Atlanta, GA, USA
The CT can and the nipple must be bonded per 250.92. There are a number of ways to do this. You could bond the neutral to the CT can and use bonding bushings on one end of the nipples with jumpers as one solution. Another way would be as implied in the drawing and use a jumper to bond one end of the nipples and also the CT can. I prefer CT cans with a factory bonding jumper so you only need to worry about bonding the nipples but there are many ways to to this. The bottom line is all metallic items on the line side must be bonded per 250.92, either by jumpers or simply connecting to the neutral.
Thank you!
A bonding locknut on one end of the metallic raceway will work also if there are no concentric or eccentric knockouts.
Thank you!
 

texie

Senior Member
Location
Fort Collins, Colorado
Occupation
Electrician, Contractor, Inspector
Note that if you have a CT can that does not have a bonded neutral you could just use a bonding locknut on BOTH ends of the nipple(s) and then it will be bonded in compliance with 250.92 as well.
 
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