External Ground Bar as GEC termination point

S

Strathead

Senior Member
Location
Ocala, Florida, USA
Occupation
Electrician/Estimator/Project Manager/Superintendent
I can't get my head around this.... A typical installation in this area is to run separate conductors for grounding electrodes, terminating all of them on a copper ground bar external to the Service Equipment and then running a 250.66 sized conductor to the equipment. To expound, in larger projects running (usually a 3/0) from electric room to electric room terminating on external ground bars utilized to terminate transformer GEC's. The terminations on the ground bars are usually lugs with bolts and nuts. First is this legal? If so, where is the nuance in 250 that allows this? I am thinking we MUST run to a ground bar INSIDE the service equipment for multiple GEC,s. We can then extend to an external ground bus and run to other electrical rooms. Also, confirm for me that 250.30 (5) and (6) that allow us to use the ground bars in separate rooms for separately derived transformers.

Not sure if I was clear with all of my issues. I will know if I see some responses.
 
Ground bars are commonly installed as you've described in commercial buildings. It allows you to run one GEC from the service to a central location and then connect your GEC's or bonding jumpers to the ground bar. As you've mentioned this can also be useful when you have several transformers in one room and do not want to run separate GEC's all the way back to the service. Basically you're setting up something like 250.64(D)(1).
 
infinity said:
Ground bars are commonly installed as you've described in commercial buildings. It allows you to run one GEC from the service to a central location and then connect your GEC's or bonding jumpers to the ground bar. As you've mentioned this can also be useful when you have several transformers in one room and do not want to run separate GEC's all the way back to the service. Basically you're setting up something like 250.64(D)(1).
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That is part of what I was looking for, but I am thinking that standard chair lugs or even crimp lugs fastened with bolts and nuts is not a listed method of attachment per 250.64(D)(1)(3). Am I correct? What method other than Cadweld or those Burndy crimps would be listed? Are there any "irreversible" bolt nut combos that can be used?
 
Strathead said:
That is part of what I was looking for, but I am thinking that standard chair lugs or even crimp lugs fastened with bolts and nuts is not a listed method of attachment per 250.64(D)(1)(3). Am I correct? What method other than Cadweld or those Burndy crimps would be listed? Are there any "irreversible" bolt nut combos that can be used?
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Are you referring to the connection to the busbar? Any listed terminal attached with a nut and bolt would be code compliant.
 
Strathead said:
That is part of what I was looking for, but I am thinking that standard chair lugs or even crimp lugs fastened with bolts and nuts is not a listed method of attachment per 250.64(D)(1)(3). Am I correct? What method other than Cadweld or those Burndy crimps would be listed? Are there any "irreversible" bolt nut combos that can be used?
Click to expand...
250.64(D)(1)(3) is giving you conditions that only apply when using this section for your method and doesn't require irreversible connection or use of terminations that are listed for grounding when connecting to the bus bar. Most any other connection in any other situation to a GEC needs to be listed for grounding and be irreversible connection.
 
Strathead said:
That is part of what I was looking for, but I am thinking that standard chair lugs or even crimp lugs fastened with bolts and nuts is not a listed method of attachment per 250.64(D)(1)(3). Am I correct? What method other than Cadweld or those Burndy crimps would be listed? Are there any "irreversible" bolt nut combos that can be used?
Click to expand...
Always thought the separate bus was good from a drawing clarity view point. EC can see exactly ALL of the connections required for the GE system...main, telco, wtr, steel, footer, etc.
On smaller to medium size services, I would give the EC the option to delete it if he opted to.

Highly recommend getting a copy of "SOARES", book on Grounding & Bonding. Every EE & EC should have a copy.
They have visuals on this topic.
 
kwired said:
250.64(D)(1)(3) is giving you conditions that only apply when using this section for your method and doesn't require irreversible connection or use of terminations that are listed for grounding when connecting to the bus bar. Most any other connection in any other situation to a GEC needs to be listed for grounding and be irreversible connection.
Click to expand...
The code section states, "listed connector". Listed for what then, and technically, what is a connector in reference to terminating conductors?
 
Strathead said:
The code section states, "listed connector". Listed for what then, and technically, what is a connector in reference to terminating conductors?
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A listed connector would be some sort of terminal as opposed to wrapping the conductor around a screw.
 
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