Service / Feeder grounding conductor

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rpottool

Member
Location
Pittsburgh,Pa.
The question is: Are grounding conductors required with the secondary conductors from a "customer owned" 23k volt 3 phase - 277/480 volt 3 phase 4 wire step down transformer to the main disconnect.
There is overcurrent protection on the primary side but not near the transformer and there is a new grounding electrode system on the secondary side bonded at the main disconnect.
The underground primary conductors are "customer owned" which I think makes them service conductors and the secondary conductors are considered feeders (230.200)
I'm not sure that I understand completely
 

iwire

Moderator
Staff member
Location
Massachusetts
The question is: Are grounding conductors required with the secondary conductors from a "customer owned" 23k volt 3 phase - 277/480 volt 3 phase 4 wire step down transformer to the main disconnect.
There is overcurrent protection on the primary side but not near the transformer and there is a new grounding electrode system on the secondary side bonded at the main disconnect.
The underground primary conductors are "customer owned" which I think makes them service conductors and the secondary conductors are considered feeders (230.200)
I'm not sure that I understand completely

You have to nail down the location of the service point, the line of demarcation between the customer and the utility. Without knowing that for sure the question cannot be answered.
 
You have to nail down the location of the service point, the line of demarcation between the customer and the utility. Without knowing that for sure the question cannot be answered.

Seems to me that the description in the OP puts the service point on the supply side of the transformer, making the exact location of the service point irrelevant to the question. I would direct rpottool to 250.30(A) and/or to Google search under images "mike holt sds grounding."
 
The question is: Are grounding conductors required with the secondary conductors from a "customer owned" 23k volt 3 phase - 277/480 volt 3 phase 4 wire step down transformer to the main disconnect.
There is overcurrent protection on the primary side but not near the transformer and there is a new grounding electrode system on the secondary side bonded at the main disconnect.
The underground primary conductors are "customer owned" which I think makes them service conductors and the secondary conductors are considered feeders (230.200)
I'm not sure that I understand completely

Regardless who owns the transformer, the secondary neutral conductor should be earth grounded at the transformer. POCO grounded all of theirs before feeding the customers, for safety reason. Anyone has good reasons for not grounding it?
 

iwire

Moderator
Staff member
Location
Massachusetts
Regardless who owns the transformer, the secondary neutral conductor should be earth grounded at the transformer. POCO grounded all of theirs before feeding the customers, for safety reason. Anyone has good reasons for not grounding it?

In most cases there will be a grounding electrode system at the transformer.

But a connection to earth is not what this thread is about.
 

iwire

Moderator
Staff member
Location
Massachusetts
Transformer and transformer primary conductors are "customer owned." How could the secondary conductors be service conductors?

We have had power companies require the customer purchase and install the equipment only to take it over and control it putting the service point on the load side of this customer owned equipment.
 
I would say if the 4 conductors were protected inside an approved metal conduit, then the bonded conduit can serve as the EGC. If they are in PVC then I don’t see the need for adding a ground conductor from transformer to the main disconnect.
 

iwire

Moderator
Staff member
Location
Massachusetts
I would say if the 4 conductors were protected inside an approved metal conduit, then the bonded conduit can serve as the EGC. If they are in PVC then I don’t see the need for adding a ground conductor from transformer to the main disconnect.

When in doubt just make stuff up.
 

rpottool

Member
Location
Pittsburgh,Pa.
The customer service point location should be at the overcurrent protection device located at the customer owned medium voltage switchboard , That should make the secondary conductors Feeders (230.200)
Since there is a grounding electrode system installed for the new building it was my position that the secondary conductors did not need an equipment grounding conductors.
The transformer has a earth grounding system (ground rods / ground bar / a 4/0 bare copper conductor

Also thanks for the feedback
 
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