Residential Backup Generator

[acolar]

Trying to put together a block diagram in order to understand the general code requirements prior to the installation of a residential natural gas powered back up generator and ensure it meets NEC. I currently have a 320A meter can which feeds into two seperate 200A panels that power the home. I was wondering if I could keep one of the panels (call it Panel "A") wired to the meter as is. But use the other panel (called panel "B") which is not fully populated as my panel which gets power from the ATS/Generator?
I propose coming off the meter into a 200A disconnect located outside the house. From the disconnect the power would go into the 2 pole 200 Amp Automatic transfer switch. (A disconnect located outside the home would also be installed between the generator output and the ATS). Then from the ATS to the 200 Amp panel (Panel "B") which I would use to feed the loads selected to be run on backup power when edison is lost.

I believe this 200A panel (panel "B") would now be treated as a sub-panel and require the grounds and neutrals to be seperated?

Also I have wondered when transfering circuits from exisiting panel "A" to the backup power panel "B" how do I add additional length to the circuits if requried? Use wire nuts? Can the splicing/wire nuts be located inside panel box "B" or are the splices to be located outside the panel "B" in some other type of enclosure?

Thanks in advance to your responses.

 

[augie47]

generator

generator

If I read your post correctly, I see a problem with the grouping of disconnects. If you add a service disconnect outside for "B" you would also need a disconnect for "A".
Both "A" & "B" interior panels would be sub panels with the neut & gr seperated.
Splicing in panel "A" and extending circuits to "B" should be acceptable.

 

[acolar]

Panel "A" & "B" are Square D 200 amp load centers with a 200 amp internal main disconnect and wired directly to the meter.

I was not sure if panel "A" would need and external 200 amp service disconnect since it would remain wired as is and not be involved with the backup power scheme.

Thanks for the quick response!