New service today

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So the GEC to water main and ground rod would have to both be bonded to the grounded conductor in the gutter

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How many grounding electrode conductor's are run from the block to the water pipe. If it is just one and a #6 then you may have an issue
 
nickelec said:
So the GEC to water main and ground rod would have to both be bonded to the grounded conductor in the gutter

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You could have sized the grounding electrode conductor for one connection to the water pipe and have one to the ground rod and tie it in at the gutter to the grounded conductor.
 
That how I sized it so the 1/0 is the second and the #2 are what not feeders ? Would the #2s feeding all the disconnects be considered multiple sets of sec and then the exception be used to size the GEC to water main

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So here's the question from the endbox to the gutter I have one set of service entrance conductors sized 1/0

Then from the gutter I have two sets going to the 4 meters of #2 ( one to each two gang meters base)

Then one set of #2 to the stand alone meter and panel

So since there is no disconnect all of the #2s are also considered service entrance conductors there for having to ass up the CMA of the 3sets to find a proper size GEC?

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Now that I am looking at 250.66 your grounding electrode conductor must be sized to the largest service entrance conductors. Since the 3 sets of #2 are service conductors then I believe you would have to base the service on 3 #2 equivalents for the grounding electrode conductor.

I believe your grounding electrode conductor needs to be based on 4/0 which is a #2
 
I see now the CMA of 3#2s is larger then that of the 1/0 so your correct

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IMO if incoming supply conductors are 1/0, the GEC is sized per that 1/0 conductor. Tapping multiple #2's onto it to go to each disconnecting means is not going to magically increase the current carrying ability of the common 1/0 supply conductor.

Should you have had a single main then split into same feeders you would have only sized the GEC to the 1/0 conductor.
 
What size are the conductors from the meter to the first disconnect? These are also service conductors and there are 5 of them so if they are #2 then you need an even larger gec
 
Dennis Alwon said:
What size are the conductors from the meter to the first disconnect? These are also service conductors and there are 5 of them so if they are #2 then you need an even larger gec
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If this installation were a meter center with main lugs and then bus bars to each socket/disconnect instead of "NEC conductors" in place of bus bars, would you size the GEC per the incoming 1/0 or to the ampacity of the bus bars?



What if it were 400 amp rated bus but only supplied with 1/0 conductor?



I still think the GEC needs sized per the incoming 1/0 conductor, what is used between the common junction point, meter and disconnecting means doesn't magically increase the current carrying abilities of the 1/0 that is coming in from the utility and it is my belief that this is what the GEC is intended to be sized to, it has no need to be able to dissipate more energy than can enter via those incoming conductors.
 
kwired said:
If this installation were a meter center with main lugs and then bus bars to each socket/disconnect instead of "NEC conductors" in place of bus bars, would you size the GEC per the incoming 1/0 or to the ampacity of the bus bars?
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No because note 2 would apply.

Think of a 400 amp service with one meter. One service has 2- 200 amp panels with 4/0 Al or 2/0 Cu service conductors to each one. The grounding electrode conductor needed is #2. Now use an all in one 400 amp meter main and now you need 1/0 grounding electrode conductor. Is that any different?



What if it were 400 amp rated bus but only supplied with 1/0 conductor?
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Again read Notes 1 and 2



I still think the GEC needs sized per the incoming 1/0 conductor, what is used between the common junction point, meter and disconnecting means doesn't magically increase the current carrying abilities of the 1/0 that is coming in from the utility and it is my belief that this is what the GEC is intended to be sized to, it has no need to be able to dissipate more energy than can enter via those incoming conductors.
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You have that right to do it your way and see if it passes. Remember it may pass but it may not be compliant.
 
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