"mxslick" nailed it!
Considering that darn Mansion in "Residential" sense, is akin to considering the "Spruce Goose" as a small Fishing Boat!
They throw some RAGING PARTIES, and I mean frikken ragers!
They normally overload the Primary Circuit's Breaker during such ragers, resulting in darkness and mad neighbors.
To avoid the "Inconvenience" of power loss during previously mentioned off-hook parties, they (the Mansion personnel) have installed 2 separate back-up gennys!
One is a "Small Unit" - 250 KW rating,
The other is a "Modest" 750 KW rating.
Both are Diesel Prime Movers
(8V92 and 12V92 may be the types, not sure... need to ask the guys/girls up there about the Prime Movers' CU³ displacement + make/model #)
The place is just really cool!
The "Remodel" took a few years overall, and upto just recently when a good friend of ours retired as Site Engineer, there was always something to do there every few months.
They feed you, give you as many Pepsi Colas as you can drink, and help move materials + etc. - even the Security Staff treats you great!
(now if you were not supposed to be there, that's another story! The LAPD would be the "Housekeeping Staff" dealt with in this alternate scenario!).
One of the most memorable things for me was seeing an Emu, poking her head over the Service Entrance Gate, while we were "On The Comm" with Security for entrance.
It was so funny - just a big old Bird's head and part of a neck, through the top part of the fence - totally staring at us.
She followed us while we drove in, all the way to the parking area - then poked her head in the passenger side window.
That was her way of saying "Hello"!
She was a real Sweetheart.
As to the GFPE deal, I asked Pops today when he remembers the first of such NEC articles.
Seems like early 1970's for him, as there was a large Industrial T.I. in Garden Grove he was involved with at this time, and was like the first GFPE he had seen and dealt with.
He was used to the "Commonly Used" 480 VAC Ungrounded Deltas.
I can still remember this job well! (I was between 8 and 9 years old at the time)
It was a HUGE Tilt-Up!
Seemed like it went on forever!
Big, beautiful Machinery inside it!!!
<enter Tim Taylor "grunts" here>
Ahhh, those were the days!
End of reminiscing