Size of GEC

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kec

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Electrical Contractor
I installed a 400A meter with 2 -4/0 Alu service entrance cables to [2] 200A panels with a main disconnect in each. Is the size of the GEC to the water pipe #4 copper based on 4/0 or do you add circular mils of both cables which than becomes #2 copper?

Thanks
 
Welcome to the forum.:)

Take a look at Note 1 to Table 250.66.

"1. Where multiple sets of service-entrance conductors are used as permitted in 230.40, Exception No. 2, the equivalent size of the largest service-entrance conductor shall be determined by the largest sum of the areas of the corresponding conductors of each set."

Chris
 
raider1 said:
Welcome to the forum.:)

Take a look at Note 1 to Table 250.66.

"1. Where multiple sets of service-entrance conductors are used as permitted in 230.40, Exception No. 2, the equivalent size of the largest service-entrance conductor shall be determined by the largest sum of the areas of the corresponding conductors of each set."

Chris
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If he is installing one conductor back to the electrode, he could size it in that fashion.

If he would like to install 2 4AWG copper conductors back to the electrode, one for each 200A panel, he could do that as well.
 
infinity said:
So this is an underground service lateral?
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It sure would be in my area, but I know some areas the POCO does overhead to the meter as well. :smile:

I have been thinking on this and I think that note 1 of Table 250.66 would require the GEC size to be based on the combined size of the service conductors on load side of the meter even if I had a single set of service conductors on the line side of the meter. That note has the infamous 'shall' in it.
 
iwire said:
It sure would be in my area, but I know some areas the POCO does overhead to the meter as well. :smile:

I have been thinking on this and I think that note 1 of Table 250.66 would require the GEC size to be based on the combined size of the service conductors on load side of the meter even if I had a single set of service conductors on the line side of the meter. That note has the infamous 'shall' in it.
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On an overhead the service entrance conductors would be on the line side of the meter and would be used to size a single GEC. Yes?
 
infinity said:
On an overhead the service entrance conductors would be on the line side of the meter and would be used to size a single GEC. Yes?
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Well I thought so until just a little while ago and reading note 1 to 250.66.

Now I think if it divides up at the meter and goes to more then one service disconnect I don't see sizing it based on the one set of service conductors on the line side of the meter as an option.
 
infinity said:
On an overhead the service entrance conductors would be on the line side of the meter and would be used to size a single GEC. Yes?
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Would the conductors on the line side of the meter in a service drop be service entrance conductors or service drop conductors?

I think the service entrance conductors would start on the load side of the meter.

Chris
 
raider1 said:
Would the conductors on the line side of the meter in a service drop be service entrance conductors or service drop conductors?

I think the service entrance conductors would start on the load side of the meter.

Chris
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Chris, IMO if the customer owns and controls the drop then that would be the NEC 'service drop', my home is served overhead and the utility controls up to the point of attachment, that being the case my home has no NEC service drop.

Service entrance conductors (going from memory eek :smile:) start at the service point and end at the service disconnect.
 
You all have me lost here. If there is an overhead service that is provided by the EC that means it is service entrance conductors? If that is the case why can I size these conductors to the calculated load when in fact I cannot on the load side of the meter.

Thus, if I had a calculated load of 198 amps but I want to make a 400 amp service where you saying that I can size my GEC to the 200 amp service conductors that I install on the line side of the meter? :confused:
 
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iwire said:
Chris, IMO if the customer owns and controls the drop then that would be the NEC 'service drop', my home is served overhead and the utility controls up to the point of attachment, that being the case my home has no NEC service drop.

Service entrance conductors (going from memory eek :smile:) start at the service point and end at the service disconnect.
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Yeah, my brain kind of froze up.I got messed up looking at the diagram at the beginning of Article 230. I agree with you.

In my area the utility owns the overhead service drop and the electrician installs the riser and service head. It has become almost a thing of the past to install a new service with a service drop. The local utility now requires a service lateral conduit to be installed by the electrician and the utility will provide and pull the service lateral conductors.

Chris
 
Dennis Alwon said:
You all have me lost here. If there is an overhead service that is provided by the EC that means it is service entrance conductors?
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Those overhead conductors would be both service entrance conductors and service drop conductors.


If that is the case why can I size these conductors to the calculated load when in fact I cannot on the load side of the meter.
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You have now lost me, a meter is nothing more then a bulge in the service entrance conductors, the location of the meter has nothing to do with conductor sizing.
 
iwire said:
Those overhead conductors would be both service entrance conductors and service drop conductors.




You have now lost me, a meter is nothing more then a bulge in the service entrance conductors, the location of the meter has nothing to do with conductor sizing.
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I thought I remember posts that you made stating that the conductors in a riser only needs to be sized to the calculated load of the house. Did I misunderstand that? I never understood why so perhaps I am mistaken.
 
Dennis Alwon said:
I thought I remember posts that you made stating that the conductors in a riser only needs to be sized to the calculated load of the house. Did I misunderstand that? I never understood why so perhaps I am mistaken.
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Oh, well I did say that about the riser for a multiple service disconnecting means, so I now understand what you mean.:smile: There is no rule that requires the split to happen at the meter, if we look at this service

IMG_1452.JPG



IMG_1465.JPG


We could size the service conductors from the meter to the split in the can just large enough for the calculated load.
 
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