I'm having a little trouble understanding the hook-up from the meter pan to the ATS from the description, and it doesn't sound kosher. Maybe I'm understanding it wrong. Sounds like the POCO feeders will be going into the ATS then feeding the meter?
In my opinon, it should go like this:
- POCO feed to METER
- METER to SERVICE DISCONNECT (400A)
- SERVICE DISCONNECT (400A) to ATS.
- ATS to 200A PANEL(S).
I'm assuming you'll be energizing BOTH 200A PANELS with the genset?
I also would put a SERVICE DISCONNECT between the genset and ATS. That's pretty much standard.
If the ATS isn't service entrance rated, like IWire mentioned, those 200A PANELS become subs, and the grounding bonding happens in the SERVICE DISCONNECT; you can use a 400A service main breaker for that, rather than a pull disco (probably cheaper).
You might also want to consider locating the ATS INSIDE the building. Even though the switch is 3R, a lot of expensive boards and relays are in there, which don't always do well with the extremes outdoors.
Does your local code or poco require switched neutrals?
Electric aside, do they have the gas service for this monster? This thing is likely gonna burn something of the order of 550,000-600,000 BTU/hr, so if the gas service is also 20 ft from the genset like the electric service, better make sure its getting fed by at least a 1 1/4" pipe.
That was just the VOLUME, you also need to consider gas PRESSURE? Most gensets require elevated gas pressure (typicaly 11" WC), well above the normal 4-6" WC supplied by the utility regulator. Often what needs to be done is a seperate regulator is needed just for the genset. The meter and pipe must also be able to accomodate the genset and other gas appliances.
Joe
