Design two critique and/or suggestions for improvement. Why I share your viewpoint about some codes (not to mention AHJ), I feel we have no choice but to adhere to them.
First, I am accustomed to seeing a “non-interruptible type” POCO supply to a hospital. So give me at least two POCO feeders with two transformers and two POCO ATS’s. Any one feeder and transformer most be capable of carrying the entire connected load.
Moving on to the main switchgear, I’d suggest breaking it down into two 2,000 amp sections. Each section shall have two main breakers (from the two different POCO transformers), and a tie breaker. Call the mains 1A, 1B and the tie 1C. Give me analog panel meters with a rotary switch so I can quickly see all load voltages and currents on breakers 1A and 1B. Make breakers 1A, 1B, and 1C draw out style. Needless to say 1A and 1B shall each be capable of supplying the entire connected load. The other section would be the same with main breakers 2A, 2B and tie breaker 2C. You will need ground fault protection on those breakers. I would not want fuses. At this point you could keep your pair of 800 amp breakers feeding NDP and SDP. They will need ground fault protection. Personally I’d give consideration to doing away with NDP and SDP and moving all loads back to the main switchgear. This way a ground fault on an 800 amp breaker isn’t taking down half my facility. Sure that is ten circuits that have to be brought all the way back and the switchgear has to have more breaker spaces. But 200-250 amp MCCB’s have about 1/3 the failure rate of the larger 800 amp breakers. Plus a ground fault on any of the 200-250 amp breakers is a much more tolerable event.
On the essential side I would require two generators, each capable of carrying the entire connected load. The generator parallel switchgear shall have generator main breakers and a tie breaker. Those shall be draw out style. Individual breakers for the ATS’s can be MCCB’s but thought should be given to ease of replacement. I would not have ground fault protection at this level. Provisions shall be made to run with either a split bus or generators in parallel. Necessary controls shall be in place to automatically and manually parallel the generators. An indicator panel shall be in place at this switchgear showing the position of each ATS. I’d prefer incandescent lamps switched thru ATS cam switches using the generator battery. The indicator panel should have a “push to test” feature so all lamps can be tested. I would want a rotary switch so I can pick which generator battery is being used for the ATS generator run command. I can’t tell you the number of times I have seen batteries changed out with no thought to disabling every ATS in a facility. Oh, and I want dual batteries and dual starters on each generator.
I would want my ATS’s to be as close to the load as possible. I would rather see you run a pair of normal power feeders to switchgear near the critical emergency power loads (i.e. OR rooms). I’d like that switchgear to have one main from section 1, one main from section 2, and tie breaker. Make them draw out style breakers. Panel meters please. As near as possible to that gear I’d want an essential power board with dual feeders from the generator parallel board. Same setup, draw out breakers with a tie breaker. By dual feeders it is assumed one feeder comes from section 1 (or generator 1) and the other comes from section 2 (or generator 2). The intent is that upon a notification of loss of power that one guy could quickly see it he has lost a normal power feeder or an emergency power feeder. He would be able to see this and restore power in mere seconds by opening a source breaker and closing a tie breaker. Then he can head to the main switchgear/parallel gear and reset a breaker. I would want all my breakers feeding individual ATS’s to have ground fault protection. IMHO I’d rather have stand alone ground fault modules and shunt trip coils. It is a lot less costly to have a couple of modules and coils in stock than a bunch of LSIG breakers. By the same token make the draw out breakers the same frame size so they can be used in multiple locations simply by adjusting trip settings. I’d want a bunch of little ATS’s in the same room as the essential gear, as in one for each and every iso, life safety, and critical panel. It would be nice for the equipment loads as well, especially the elevators and MCC. The one place I would use fuses is at the end of the line, like before every motor. I would use NEMA rated motor starters with electronic overload relays. It cuts down on the need to stock heater elements and guys putting the wrong size ones in.
So there you are! I could spend a lot more of the customers money and require 1,200 RPM prime rated gen sets with 96 hours of fuel (and of course I’d want dual tanks and dual STP’s on each tank and four separate pairs of fuel lines). And of course, given my name, I favor Russelectric gear. No doubt Siemens will ruin my stuff.