Service Ground from CT Cabinet?

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kwired

kwired

Electron manager
Location
NE Nebraska
Are you asking if you can have the system bonding jumper in the CT cabinet and no bonding jumper in the service disconnect(s)?

If so you must have separate grounded and grounding conductors run to service disconnect(s).
 
H

hurk27

Senior Member
Location
Portage, Indiana NEC: 2008
Not sure if you can:

250.24(B) Main Bonding Jumper. For a grounded system, an
unspliced main bonding jumper shall be used to connect the
equipment grounding conductor(s) and the servicedisconnect
enclosure to the grounded conductor within the
enclosure for each service disconnect in accordance with
250.28.
Click to expand...

Sounds like it must be "within" the service disconnect?
 
iwire

iwire

Moderator
Staff member
Location
Massachusetts
I agree with Hurk, regardless of a bond at the CT cabinet you must bond at the service disconnect.

This happens in 100s or thousands of homes across the US in meter sockets and service disconnects.
 
H

hurk27

Senior Member
Location
Portage, Indiana NEC: 2008
I want to point out that while the MBJ has to be at the main service disconnect, the grounding electrode conductor is allowed to be connected to the grounded conductor at or ahead of the MBJ, not after, they can be run to the CT cabinet or meter (if POCO/AHJ allows) and or even up to the drop connection, the NEC allows this for flexibility of keeping your GEC runs short, and the fact the grounded conductor serves as the EGC ahead of the MBJ. See 250.24(A)(1)

We hear all the time that the GEC's have to land at the same place the MBJ is made but this is not really true, as we can see it can be landed anywhere ahead of the MBJ up and to the service drop location, or lateral connection in the meter/CT cabinet
 
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iwire

iwire

Moderator
Staff member
Location
Massachusetts
I again agree with Hurk,

Here are the appropriate code sections to go along with it.




250.24 Grounding Service-Supplied Alternating-Current
Systems.

(A) System Grounding Connections. A premises wiring
system supplied by a grounded ac service shall have a
grounding electrode conductor connected to the grounded
service conductor, at each service, in accordance with
250.24(A)(1) through (A)(5).

(1) General. The grounding electrode conductor connection
shall be made at any accessible point from the load end
of the service drop or service lateral to and including the
terminal or bus to which the grounded service conductor is
connected at the service disconnecting means.

(B) Main Bonding Jumper. For a grounded system, an unspliced
main bonding jumper shall be used to connect the
equipment grounding conductor(s) and the service-disconnect
enclosure to the grounded conductor within the enclosure for
each service disconnect in accordance with 250.28.

Exception No. 1: Where more than one service disconnecting
means is located in an assembly listed for use as service
equipment, an unspliced main bonding jumper shall
bond the grounded conductor(s) to the assembly enclosure.

Exception No. 2: Impedance grounded neutral systems
shall be permitted to be connected as provided in 250.36
and 250.186.
Click to expand...


We need the bond at the CT cabinet or meter socket to ground the enclsure and this is allowed

250.142 Use of Grounded Circuit Conductor for
Grounding Equipment.

(A) Supply-Side Equipment. A grounded circuit conductor
shall be permitted to ground non–current-carrying metal
parts of equipment, raceways, and other enclosures at any
of the following locations:

(1) On the supply side or within the enclosure of the ac
service-disconnecting means

(2) On the supply side or within the enclosure of the main
disconnecting means for separate buildings as provided
in 250.32(B)

(3) On the supply side or within the enclosure of the main
disconnecting means or overcurrent devices of a separately
derived system where permitted by 250.30(A)(1)
Click to expand...
 
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