Main rated current vs Bus rated current in Meter banks

[Smart $]

I wonder as well. An Article 220 calc by definition already includes any continuous load (if any). You don't need to add any load as continuous again.

Yes, it includes continuous loads but does not include factoring 125%. That's in 210, 215, 230.

More to the point, residential installations seldom have continuous loads.

 

[shortcircuit1]

I would agree that this is somewhat like a tap. The the smaller bus is protected from overload by the downstream OCPD and short circuit/ground fault is provided by the upstream main OCPD. It's similar to a MCC where the horizonal and vertical buses will be different sizes. I think the OP is not recognizing the distinction between overload and short circuit/ground fault.

I was referring to more on a short circuit basis when i said if the current goes beyond 1200A bus rated ampacity..Its highly unlikely that your load is going to go over 1200A.