Using Ground Bars at Service

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ckdckd

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I have a question about using ground bars (NEC 2011). I was asked if a large common ground bar could be placed next to a bldg's service disconnect for convenience of bonding ALL electrodes at a single point, including the grounding electrode conductor from the service equipment.
(See horrible graphic at bottom of post for a "visual" of what I am trying to explain.)

I think this would violate 250.64(C), but I have seen it often enough to make me wonder if I am missing something. Can somebody please clarify?

Also, this is for a main service to a building, indoor 1600A, 480V, Service equipment. It is not for a separately derived system.

<-------- [ground Rods] <-------- [Ground Bar] <-------- [Neutral Bus in Main Service Disc.]
<-------- [Water Main]
<-------- [Bldg Steel]
<-------- [Etc. ]
 
In my opinion, it is permitted by 250.64(F) however 250.64(C) does not say that. 250.64(C) has a reference to 250.68(C) that permits the building steel or metal water piping to be used like the bus in your example.
 
don_resqcapt19 said:
In my opinion, it is permitted by 250.64(F) however 250.64(C) does not say that. 250.64(C) has a reference to 250.68(C) that permits the building steel or metal water piping to be used like the bus in your example.
Click to expand...
I agree. The required part most tend to skip over is in 250.64(F)(3), where it states "Connections shall be made by a listed connector or by the exothermic welding process." Not certain where a listed connector falls in the requirement, but the exothermic welding process definitely complies with 250.64(C).
 
ckdckd said:
I have a question about using ground bars (NEC 2011). I was asked if a large common ground bar could be placed next to a bldg's service disconnect for convenience of bonding ALL electrodes at a single point, including the grounding electrode conductor from the service equipment.
(See horrible graphic at bottom of post for a "visual" of what I am trying to explain.)

I think this would violate 250.64(C), but I have seen it often enough to make me wonder if I am missing something. Can somebody please clarify?

Also, this is for a main service to a building, indoor 1600A, 480V, Service equipment. It is not for a separately derived system.

<-------- [ground Rods] <-------- [Ground Bar] <-------- [Neutral Bus in Main Service Disc.]
<-------- [Water Main]
<-------- [Bldg Steel]
<-------- [Etc. ]
Click to expand...

The external ground you have probably seen used in other installations is allowed in 250.64(D)(3), but is limited to:

(D) Building or Structure with Multiple Disconnecting
Means in Separate Enclosures.

For a service or feeder with two or more disconnecting means in separate enclosures sup-
plying a building or structure, the grounding electrode connections shall be made in accordance
with 250.64(D)(1), (D)(2), or (D)(3)
Click to expand...

Why? I do not know.:? The method seems that it would be fine for your install and similar.
 
Not sure what ground bar you mean but tha

(c) Connections. All tap connections to the common
grounding electrode conductor shall be made at an accessible
location by one of the following methods:
(1) A connector listed as grounding and bonding equipment.
(2) Listed connections to aluminum or copper busbars not
smaller than 6 mm × 50 mm (1⁄4 in. × 2 in.). If aluminum
busbars are used, the installation shall comply
with 250.64(A).
(3) The exothermic welding process.
Tap conductors shall be connected to the common
grounding electrode conductor in such a manner that the
common grounding electrode conductor remains without a
splice or joint.t make some heavy duty busbars that are made for this purpose
Click to expand...
 
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