Feeding multiple panels from one feed

[jackthereal]

Good Afternoon!

Greetings all, my name is Jack and I'm a recent grad, as green as it gets, just starting out in the electrical engineer design world.

My question is in regard to feeding multiple panels from one feeder:

I have a main switchboard with a 200A feed to an ATS, which continues to feed through three 200A MLO panels (basement floor, first floor, second floor). The conductors are sized (4)4/0 & (1)#4G in a 3" conduit. These feed from one panel to the next through each floor.

Would someone please help me understand why this single set of conductors can feed these three 200A MLO panels? Is it possible to splice and extend this feed for additional 200A panels? I'm reading through the NEC now to try to find some reference...a point in the correct direction would be very appreciated!

All the best,

Jack

 

[charlie b]

First of all, welcome to the forum.

Secondly, I have to run to a meeting shortly, so I will have to let someone else give you the code references. But what you describe can be acceptable. The only constraint is that the total load cannot exceed the 200 amp limit of the transfer switch. I can have a panel with a 20 amp breaker that serves a load that will only draw 1 amp. So the combined ratings of the breakers and the panels do not matter.

 

[infinity]

Each panel is rated at 200 amps so they're protected by the 200 amp OCPD ahead of the ATS. You can used feed through type panels instead of a splice to go from one panel to another. Here's a 400 amp feed through, although the two panels are adjacent to each other they are not required to be. You could splice the feeder if you so choose also.

 

[charlie b]

Take a look at 408.36, and let us know if that answers your question.

 

[jackthereal]

This is all very helpful! Thank you for helping me understand.

Essentially, as long as the total connected load does not exceed 200A, it is safe to use this method.

Thanks again,


Jack