GEC for 3800A Service

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sparky315

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New York
Hello everyone,

We are installing a new 120/208v 3800A service in a commercial building. There are no drawings or specs to go off of, more of a design build job.

The switchgear is made up of 3 sections of busbar, one service disconnect switch and two distribution panels.

We are using two of the sections of gear to land our wire. Each section will have 8 parallel feeds of 500kcmil copper conductors which makes 16 conductors per phase. So essentially 2, 3800A feeds from two utility vaults. One vault to one section, the second vault to another.

I am being told that we need to bring 2 GECs to the water pipe and 2 supplemental GECs to building steel (a set for each section).

My question is, since the sections share the same bus, A B C N and G, do we need to do this or could we just bring one GEC to the main water pipe and one supplemental GEC to building steel?

Any help is appreciated, thank you.
 
The GEC's will go to the single service disconnect, one for each electrode if you run two separate GEC's. #3/0 copper is the largest required for the water pipe or building steel.
 
sparky315 said:
The switchgear is made up of 3 sections of busbar, one service disconnect switch and two distribution panels.

We are using two of the sections of gear to land our wire. Each section will have 8 parallel feeds of 500kcmil copper conductors which makes 16 conductors per phase. So essentially 2, 3800A feeds from two utility vaults. One vault to one section, the second vault to another.
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Am I reading this correctly: one of the service feeders lands on busbar in a distribution section?
 
The only way this makes sense to me is that the bus bar sections are just there as a place to land the wires from the utility. They then feed the disconnect switch which feeds the distribution panels. I don't know why you need 16 500 KCM wires though for a 3800 amp service.
 
petersonra said:
The only way this makes sense to me is that the bus bar sections are just there as a place to land the wires from the utility. They then feed the disconnect switch which feeds the distribution panels. I don't know why you need 16 500 KCM wires though for a 3800 amp service.
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Still, doesn't make sense. 8 sets of 500's are only good for 3040A (double-ended supply) and 16 sets are absolute overkill for a 3800A service.
 
10 sets of copper 500 kcm would make sense for a 3800 Amp service.

It would kind of make sense that they picked an odd service size to make do with the most economical wire solution but 16 sets just does not make any sense to me at all.
 
petersonra said:
10 sets of copper 500 kcm would make sense for a 3800 Amp service.

It would kind of make sense that they picked an odd service size to make do with the most economical wire solution but 16 sets just does not make any sense to me at all.
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Aluminum and voltage drop?

:blink:
 
Smart $ said:
Aluminum and voltage drop?

:blink:
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would need to be a long run to justify that much AL, especially given that if it is a 3800 Amp service it will probably never see much more than 2000 Amps of load for any real length of time. I would bet the average load is probably under 1500 A.
 
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