objectional cuurent

bigike1616

Member
Location
miami, Florida
If my service disconnecting means is located inside my branch circuit distribution panel (service rated with bond screw) , therefore bonding my grounded conductor with my grounding condutor at my panel where all my branch circuits are (service bonding jumper) which would now bond my neutrals to the case as well as to my ground fault path would this not add objectional current throughout my system?
 

Little Bill

Moderator
Staff member
Location
Tennessee NEC:2017
Occupation
Electrician
@ bigike,
Your profile says you are an industrial electrician. That said, the bonding/grounding in industrial is the same as in residential. Assuming you were speaking of a house panel. Even if not, the same principle applies to any service. The neutral (Grounded) conductor is bonded to the EGC and can/cabinet at the first disconnect with OCP, then no further bonding is allowed downstream of that.

Welcome to the forum!
 

Smart $

Esteemed Member
Location
Ohio
Upstream at the meter is allowed.
True.

But there could be objectionable current when electrically-solid metallic wiring methods are used upstream. Using a non-metallic wiring method, whether for the entire length or just a single fitting, would effectively reduce, if not eliminate that potential.
 

Little Bill

Moderator
Staff member
Location
Tennessee NEC:2017
Occupation
Electrician
True.

But there could be objectionable current when electrically-solid metallic wiring methods are used upstream. Using a non-metallic wiring method, whether for the entire length or just a single fitting, would effectively reduce, if not eliminate that potential.
I hope you are talking about raceways/conduit or cables. If not, you've totally lost me.:?:)
 

Smart $

Esteemed Member
Location
Ohio
I hope you are talking about raceways/conduit or cables. If not, you've totally lost me.:?:)
Yes, conductive materials that are in addition to the wires themselves and required to be bonded: metallic raceways, sheaths, etc. ...effectively creating a parallel path for neutral current.
 

Smart $

Esteemed Member
Location
Ohio
True, but since it is required by code that makes the current on the parallel path no longer objectional.
Using the grounded conductor for bonding service raceways and equipment is not required... just permitted... whereas 250.6 is required.
 
But only after the first disconect. Before that the current ceases to be objectional and changes to what,,,? Normal?

Once I got my head around which current is objectional a lot of what is in art. 250 became less blurry. I think a lot of electricians have had the a similar experience.

If you want to have some real fun discuss grounding with a lineman.
 

Smart $

Esteemed Member
Location
Ohio
But only after the first disconect. ...
You'll have to cite the specific section which requires bonding with the grounded conductor on the supply side of a service disconnecting means.

In the meantime, I reference 250.142(A)(1) to make my point.


[...and few lineman comprehend premises grounding per NEC]
 
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