Main Switchboard and Distribution Breakers

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Samardas

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Los Angeles, CA, United States
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Electrical Engineer
An 800A 208/120V 3 Ph, 4 Wire service from the Utility is being asked for (Could also be 120/240V, 3 phase) in So California. Can the same switchboard have a 40 x 20A circuit breakers for distribution or do I need separate two (2) 400A Panels with 20A distribution breakers in each (up to 24 in each, total 48) that need to be fed from the Main 800A Switchboard. The situation is, there are 40 Truck Stalls in a parking lot each needing one 20A Receptacle and the Utility service switchboard is 800A. If all 40 x 20A breakers are allowed to be in the same Switchboard making it a distribution panel as well, then the customer does not need to buy separate panels. Your assistance will be highly appreciated. Thanks, Samar
 
Allowed. Forty 20a breakers does not mean 800a will actually be used.

As long as you're talking about 120v circuits, you only need 40 spaces.
 
Samardas said:
An 800A 208/120V 3 Ph, 4 Wire service from the Utility is being asked for (Could also be 120/240V, 3 phase) in So California. Can the same switchboard have a 40 x 20A circuit breakers for distribution or do I need separate two (2) 400A Panels with 20A distribution breakers in each (up to 24 in each, total 48) that need to be fed from the Main 800A Switchboard. The situation is, there are 40 Truck Stalls in a parking lot each needing one 20A Receptacle and the Utility service switchboard is 800A. If all 40 x 20A breakers are allowed to be in the same Switchboard making it a distribution panel as well, then the customer does not need to buy separate panels. Your assistance will be highly appreciated. Thanks, Samar
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I'd like to know how 40 20 amp 120 volt receptacles, even fully loaded, needs an 800 amp 3 phase service. Forty, 20 amps recepts. on a 208/120 supply is only about 200 amps. And that does not even include load diversity. And you casually mention it could be a 120/240 3 phase service. How do you think you are going to use that given all your load is 120 volt?
 
Thank you both Larry and Electrofelon.
Larry, yes, I understand what you mean, but since it is a straight feed to each truck stall, I am considering 40 x 20A breakers for 40 trucks and asking for 800A.
So, there is no code restriction/violation for using an 800A Switchboard to ALSO act as a Distribution Panel, right?

Thanks for your quick response Larry and Electrofelon.
Stay Well & Stay Safe!
 
Hi Texie,

You are right, I think the owner wants to have an 800A service for other use. Distributing 800A, 120V, among three phases, they do not need 800A service, rather a 300A service should suffice.

However, my main worry is if I am violating any code by using an 800A service Switchboard as a Distribution panel of 40 x 20A circuits (breakers) as well.

Thanks, Stay Well & Stay Safe!
 
Samardas said:
So, there is no code restriction/violation for using an 800A Switchboard to ALSO act as a Distribution Panel, right?
Click to expand...

There may be something in the NEC (article 408) or the product standard for switch boards (UL891) that says something about there being a separate service section/compartment, but it would be a academic since the manufacturer would build it in a compliant manner.
 
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