overcurrent protection

[copper123]

Hello
Is there any code reference/violation for a panel that has multiple subpanel feeds going out of it, if the panel has overcurrent protection on the line side ( main breaker)and has the proper wire feeding it? I know this is kind of confusing, but I really dont know how to word it correctly. A couple of examples:

A 200 amp rated QO panel feeding with 3/0 copper, feeding directly into a main lug breaker mounted in the panel. This panel then directly feeds five, 100 panels in a large residential home. I ran into this the other day. The installer has added the larger nuetral lugs accesories that mount directly on nuetral bars. three on one side, Two on the other. I guess this installation would act like a I line panel that you would see in a more commercial setting.
I cant find anything wrong with it in my code book. You have overcurrent protection and the nuetral bar is rated for the load. Any problems anybody can see??

Example 2

Combination meter main. Meter with a 8 space distribution panel in the same gear. This particular one is a homeline meter main. The combo distribution panel is fused with a 200 main breaker that feeds the buses. The electrian fed out the main lugs to the house with a 200 amp feeder, and then feed a garage with a two pole 100.
Again, pretty much the same thing. I guess I am not used to see high ampacity loads in residential gear like this. If the overcurrent protection is correct, I can't find any problems. Am I correct?
Thanks

 

[bphgravity]

Re: overcurrent protection

There is no limit to the number of panelboards that can be served from one service. The important issue is total current-carrying capacity and the load to be served. As long as your total calculated load does not exceed the rating of the service entrance, you can install as many loadcenters as desired. The same goes for feeders. Whatever load is to be placed on any particular panel must not exceed the rating of the conductors serving it.

By adding a 100-ampere panel to existing 200-ampere service does not magicaly provide you with 300-amperes of capacity. In most cases, it just provides you with more space for more circuits.

 

[tonyi]

Re: overcurrent protection

Its fine - I often do multiple panels like this because it winds up being faster and easier to install than dragging a slew of long homeruns to a single main panel (particularly true in an old work scenario). The heavy feeders which usually turn out to be lightly loaded also help out a lot on eliminating end point voltage drops when those panels are located closer to the loads they serve.