Sizing Grounding Electrode Conductor

Status
Not open for further replies.

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
Situation:
Modular meter pak.. 4 meters/4 200 amp breakers all in one enclosure, service conductors to the pak to be POCO supplied. Feeders are 3/0..
Actual calculated load is < 200 amps total.
POCO is supplying with an underground 4/0 lateral.
What size grounding electrode conductor is required to the building steel,
 

raider1

Senior Member
Staff member
Location
Logan, Utah
Gus, take a look at Note 2 of Table 250.66. This applies to service that do not contain service entrance conductors.

Chris
 

Smart $

Esteemed Member
Location
Ohio
IMHO he has service conductors
...but no service-entrance conductor, which Table 250.66 is based on, and note 2 specifies where none exists the equivalent [minimum] size be used to determine GEC size.

I agree a minimum #4 is required.
 

iwire

Moderator
Staff member
Location
Massachusetts
...but no service-entrance conductor, which Table 250.66 is based on, and note 2 specifies where none exists the equivalent [minimum] size be used to determine GEC size.

IMO the conductors, either wire or bus bars between the POCO conductors and the four individual disconnecting means are service entrance conductors.
 

Smart $

Esteemed Member
Location
Ohio
IMO the conductors, either wire or bus bars between the POCO conductors and the four individual disconnecting means are service entrance conductors.
According to the definitions, both overhead and underground service-entrance conductors end at the terminals of the service equipment.

Being the meters and disconnects are in one enclosure, the entire enclosure is IMO service equipment.

Debatable? Yes.

The definition of service equipment states "connected to the load end of service conductors", thereby opening the possibility of no service-entrance conductors. Yet, "The necessary equipment... intended to constitute the main control and cutoff of the supply" part of the definition, along with the meter pack containing equipment not necessary for the control and cutoff of the supply, could easily be interpreted as the necessary equipment is not connected to the load end of either overhead service conductors or service lateral conductors, thereby opening the possibility of internal conductors (wire or busbar) being service-entrance conductors.
 
Last edited:

iwire

Moderator
Staff member
Location
Massachusetts
According to the definitions, both overhead and underground service-entrance conductors end at the terminals of the service equipment.

I agree, you are right.

I had stopped at 'service conductors' and did not look at 'service entrance conductors'.
 

erickench

Senior Member
Location
Brooklyn, NY
If we were to assume that a hypothetical service conductor were sized the same as the feeder i.e. 3/0 then NEC 250.62(D) would apply. These imaginary SEs would be tapped from the service lateral i.e. 4/0.
 
Status
Not open for further replies.
Top