Doing a job in a commercial building with a 600 amp service section that has 2 - 100 amp panels and 1 - 200 amp panel there already. They are moving in machines and work tables I'll put drops in for.
I will probably need to add another 200 amp panel. Would that be considered a sub-panel? Do I need to isolate the neutrals and grounds in it? The other panels are not the bolt-in type breakers. I believe snap in breakers are ok for a commercial biulding, correct?

Is the new panel going to be supplied from (1)the existing panel or (2) connect directly to the utility company / service conductors ?
If (2) treat it as a service and label the main disconnect "Service Disconnect" (110.22) Number one of XX, no more than six.
If (1) it is a sub panel and label the main breaker "MAIN" (110.22)
In sub panels seperate in service panels bond.
Alan-- Inspector
Note. had the 1 & 2 reversed. It is correct now
[This message has been edited by Alan Nadon (edited 07-23-2005).]

[This message has been edited by Alan Nadon (edited 07-24-2005).]

[This message has been edited by Alan Nadon (edited 07-24-2005).]

It'll be fed from the main service section with a shut off with 3 - 200 amp fuses.

The "shut off" with the three fuses is the service disconnect.
You write "with" not "from".
Is the shut off in the service or in the new panel ?
If in the service then it is the service disconnect and use four wire from there to the new panel. (2)
If in the new panel then the new panel is an additional service disconnect. (1)
*Note I got my 1 & 2 reversed in the last post I have edited it.
Alan--Inspector.

The 200a shut off is in the service cabinet. I will get a 200a load center for the panel. The load center would be considered a sub-panel I believe, from the service section disconnect. So will probably have to isolate the neutrals and grounds.

The NEC does not address Bolt-in or Plug-on brekaers. The choice of breaker mounting style is strictly a design issue. that said, most specifications call for bolt-on breakers becuse that prevents contractors from installing "loadcenters" instead of "panelboards".

Note: neither the NEC nor UL consider loadcenters to be different from any other panelboard. the difference in the panels is strictly a tradition not a standard. Think 4x4 pickup versus a 1/2 ton. It comes down to personal preference and available options only.

Wouldn't the short circuit ratings be higher on a panelboard? Most of the ones I run into in cinema work are. A lot are also "Series Rated" for fault current management.

I wouldn't want a resi loadcenter in one site I work at. The theatre is literally right on top of a network distribution transformer! A short in the projector's maint. receptacle took out the 225 amp subpanel breaker with a nice loud bang! (It tripped, didn't explode.) That same fault would've probably rearranged the buss bars on a loadcenter!

Nor sure I see the difference between a load center and a panelboard. What article in the code book shows the size of ground wire for the 200 amp panel? Should be # 6.