separate grounding electrodes for a service . . . . .

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brantmacga

brantmacga

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Location
Georgia
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Former Child
I've received the final approved plans for an upcoming job that involves upgrading a service.


Existing is 600A 120/208; we have to add another 200A 120/208 disconnect (and interior panel), trench new service conductors from xfrmr pad through existing CT can.

customer/poco doesn't want to replace existing CT cab or disconnect and have a single 800A.


anyhow, the city required the engineer to spec two new electrodes connected to the 200A disconnect w/ #4cu, and also run #4cu to building steel and water lines.


I sent the chief plans examiner an email questioning this (since it was he that required it) -

250.58 Common Grounding Electrode. Where an ac system
is connected to a grounding electrode in or at a building
or structure, the same electrode shall be used to ground
conductor enclosures and equipment in or on that building or
structure. Where separate services, feeders, or branch circuits
supply a building and are required to be connected to a
grounding electrode(s), the same grounding electrode(s) shall
be used.Two or more grounding electrodes that are bonded together
shall be considered as a single grounding electrode
system in this sense.
Click to expand...


He argued that we have two services with a common meter. Ok, so the code i cited still applies; he disagrees.

Anyway, not going to argue it. When the inspector turns it down, we'll make necessary changes and bill as a change-order.

I had concerns about using the #4 paralleling with the 600A's bonding connections that are already in place. Plans examiner said it doesn't matter, we're going to do it his way. Anyone else think I'm wrong or know of a code I've missed somewhere?
 
infinity said:
Can't you just tap off the existing GEC and hit the new 200 amp disconnect?
Click to expand...

that's what i asked to do; from what i see in the article i cited, that is what is required.


plans examiner says that is incorrect; he says a separate service requires a new grounding electrode. the same code i sent him specifically says you are required to do this.


he couldn't provide me with a reference.


i assume that i'm correct until shown otherwise.
 
brantmacga said:
that's what i asked to do; from what i see in the article i cited, that is what is required.


plans examiner says that is incorrect; he says a separate service requires a new grounding electrode. the same code i sent him specifically says you are required to do this.


he couldn't provide me with a reference.


i assume that i'm correct until shown otherwise.
Click to expand...
Just for clarification, the section you quoted requires the same grounding electrode(s) to be used... not the same Grounding Electrode Conductor(s). The latter can be used if sized appropriately for both services.
 
What is the existing Grounding electrode system? Is it already connected to building steel?
 
You have one service with multiple disconnects.

Each disconnecting means can have separate GEC ran to it, they can all tap to a common GEC if sized large enough for everything, or GEC sized for everything can be ran to a point ahead disconnects like to service drop or lateral and only one GEC is required if connected at this point.

Your city guy needs to learn there is more than one code compliant way to do things most of the time.

Send him to this site - hopefully we will straighten him out.
 
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kwired said:
You have one service with multiple disconnects.

Each disconnecting means can have separate GEC ran to it, they can all tap to a common GEC if sized large enough for everything, or GEC sized for everything can be ran to a point ahead disconnects like to service drop or lateral and only one GEC is required if connected at this point.

Your city guy needs to learn there is more than one code compliant way to do things most of the time.

Send him to this site - hopefully we will straighten him out.
Click to expand...

Separate GEC yes but shouldn't the electrodes (if multiple electrodes used) be connected? One disconnect may need a 1/0 GEC and the other a #4 GEC but they should connect to a common electrode system, connected building steel may quallify as connecting the electrode system.
 
kwired said:
You have one service with multiple disconnects.
Click to expand...
This is a technically correct assessment. I mistakenly called it two services in earlier post.

kwired said:
Each disconnecting means can have separate GEC ran to it, they can all tap to a common GEC if sized large enough for everything, or GEC sized for everything can be ran to a point ahead disconnects like to service drop or lateral and only one GEC is required if connected at this point.
Click to expand...
While highlighted-text method would be appropriate for some systems, I do not believe it is for the system in question. He has two laterals. The GES can only be connected to the load end of laterals, which are in the service disconnecting means.

kwired said:
Your city guy needs to learn there is more than one code compliant way to do things most of the time.

Send him to this site - hopefully we will straighten him out.
Click to expand...
True... but no guarantee he'll visit. Advise printing the thread and handing it to him in person.
 
Smart $ said:
This is a technically correct assessment. I mistakenly called it two services in earlier post.


While highlighted-text method would be appropriate for some systems, I do not believe it is for the system in question. He has two laterals. The GES can only be connected to the load end of laterals, which are in the service disconnecting means.


True... but no guarantee he'll visit. Advise printing the thread and handing it to him in person.
Click to expand...

A service lateral does not always end in the disconnecting means.

Some inspectors (and even other people) think they know everything and are never wrong - those individuals are the ones that need to be educated by a site just like this one - nobody says it will be easy to get them to come here and actually read and learn, but if they do come here they are likely to see read examples from time to time of what they are doing wrong and possibly learn from it.
 
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