Conduit bonded

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
If you're asking what I think you're asking, only one end of a nipple needs to be bonded. You're assuring the conduit is well-connected to the neutral, not using the conduit as a short-circuit current pathway.
 
If you're asking what I think you're asking, only one end of a nipple needs to be bonded. You're assuring the conduit is well-connected to the neutral, not using the conduit as a short-circuit current pathway.
I think using the conduit as a fault path is ok, it's using the conduit to cabinet/box/trough interface with a standard lock nut that is to be avoided.
 

hhsting

Senior Member
I think using the conduit as a fault path is ok, it's using the conduit to cabinet/box/trough interface with a standard lock nut that is to be avoided.
Would it not split currents some.thru neutral and some thru conduit if both ends of the conduit are connected bonded to neutral which is bad for detecting current in case of fault for breaker to trip? I think 250.92(A)(1) has exception if 250.80 is applied which is not to be bonded again if equipment is connected to neutral.
 
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al hildenbrand

Senior Member
Location
Minnesota
Occupation
Electrical Contractor, Electrical Consultant, Electrical Engineer
Would it not split currents some.thru neutral and some thru conduit if both ends of the conduit are connected bonded to neutral which is bad for detecting current in case of fault for breaker to trip?
There is a fundamental understanding here to get. The conductors on the Supply Side of the Service Disconnect(s) are Service Conductors. What you are calling neutral is the Grounded Service Conductor. The Supply Side of the Grounded Service Conductor begins at the Main Bonding Jumper(s) IN the Service Disconnect(s). On the Supply Side all the conductive parts must be bonded together so, that at minimum, a single fault from an energized Service Conductor will flow back to the Source (usually the power company transformer secondary) and the only overcurrent protective devices are at that transformer..

The Neutral Conductor exists (along with the Equipment Grounding Conductors and Grounding Electrode Conductors) on the LOAD Side of the Service Disconnect Main Bonding Jumper.
 

hhsting

Senior Member
There is a fundamental understanding here to get. The conductors on the Supply Side of the Service Disconnect(s) are Service Conductors. What you are calling neutral is the Grounded Service Conductor. The Supply Side of the Grounded Service Conductor begins at the Main Bonding Jumper(s) IN the Service Disconnect(s). On the Supply Side all the conductive parts must be bonded together so, that at minimum, a single fault from an energized Service Conductor will flow back to the Source (usually the power company transformer secondary) and the only overcurrent protective devices are at that transformer..

The Neutral Conductor exists (along with the Equipment Grounding Conductors and Grounding Electrode Conductors) on the LOAD Side of the Service Disconnect Main Bonding Jumper.
Understand everything supply side has to be bonded or connected to neutral or grounded service conductor.

Going back to post #1 question was does this bonding in attachment happen at the service disconnect end of conduit thru supply bonding jumper as well as the trough end of the conduit or just one end service disconnect end. Do both ends of conduit have to be bonded or connnected to neutral or just one end of the conduit?
 

al hildenbrand

Senior Member
Location
Minnesota
Occupation
Electrical Contractor, Electrical Consultant, Electrical Engineer
Here. The thought that a fault current on the Supply Side, whether divided or not is sensed by an overcurrent protective device gives away your confusion.
 

al hildenbrand

Senior Member
Location
Minnesota
Occupation
Electrical Contractor, Electrical Consultant, Electrical Engineer
On the Supply Side of the Main Bonding Jumper fault current takes ALL AVAILABLE parallel paths back to the Source. A single fault current path is rare.
 
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