Grounding for building fed from another building.

olc

Senior Member
Church and Rectory - The main service is in the Rectory and there is a feeder to the Church. They are separate buildings with a bridge connection. The buildings and service are quite old (service probably 60 plus years).
It does not look like the church is separately grounded.
A concern enough to correct?
 

olc

Senior Member
By bridge I mean what is basically an enclosed hallway, open below, running maybe 40-50 feet between the structures with doors at each end.


The feeder for the church is 400A (3 ph) running underground (conduit). I don't know if there is a EGC with the feeder (I don't think so).


I agree NEC 250.32 would come into play if it were a new build. I don't think there was a 250.32 when the service was installed.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Electrical Contractor
If there is a roof attached between the buildings then this is often seen as one structure. In the past, if it was considered a separate structure a 3 wire feeder was allowed with no equipment grounding conductor. Today you would need a 4 wire feeder
 

kwired

Electron manager
Location
NE Nebraska
Is there conductive paths between the two "buildings"?

Was they completely separate at one time then the link between the two built sometime later?

NEC doesn't define these as two separate buildings, but many AHJ's will consider them two separate buildings, often will want to see a two hour separation between them, and circuits from one "building" can not cross that separation and supply items in the other building, that usually makes the "bridge" part of one building and the separation point at one end of that bridge.
 

olc

Senior Member
I am pretty sure it is a 4 wire feeder. Just no ground other than the conduit (and the neutral).

I would call it a separate building.
I'm just wondering if there is good grounding in the church.


Actually there is a newer small panel near the church distribution that has neutrals and ground wires connected to the same buses.


The question is a bit academic.
It is an existing condition so does not need to be changed unless the distribution equipment is replaced.
As far as the ground goes - it has been this way 6o odd years.
 
Last edited:

kwired

Electron manager
Location
NE Nebraska
I am pretty sure it is a 4 wire feeder. Just no ground other than the conduit (and the neutral).

I would call it a separate building.
I'm just wondering if there is good grounding in the church.


Actually there is a newer small panel near the church distribution that has neutrals and ground wires connected to the same buses.


The question is a bit academic.
It is an existing condition so does not need to be changed unless the distribution equipment is replaced.
As far as the ground goes - it has been this way 6o odd years.
If it is a separate building it once was compliant to run 4 wires (three phase) or 3 wires (single phase) and bond the neutral at the first disconnect and install a grounding electrode system just like you did for a service. I don't know about 60 years ago, but near the end of when this was still allowed (either 2005 or 2008 I believe was when you could no longer do this) there was wording that prohibited it if there was other conductive pathways between the two buildings that could end up carrying parallel neutral current.
 

olc

Senior Member
The plot thickens.
I have visited the building an discovered a second feeder between the buildings.
The service is in the Rectory.
The main feeder to the church is 400A underground to a distribution in the rear of the church. (there are 6 disconnects there).
There is a second 200A feeder underground to near the front of the church. (I didn't see it before as it went straight out the back of the distribution panel). It feeds one disconnect near the front of the church.


It is possible that the 200A predates the 400A feeder as the 400a distribution in the back is in a sort of shed structure built off the back of the church.
Service is 120/208, 3 ph if I did not say so before.
 
Top