As noted by Dave B.  We began the orderly shutdown of the site at 1500 local time on Friday.
The power actually went out at 1715 and we were almost ready.
Vacuum system with the generators setup did not go as smoothly as it could.
1. Generator output was too low for the UPS to operate on.  UPS looking for 115V and we were at 112V.  We bypassed the UPS and ran the 24V dc supplies directly from the Generator.
2. The GFI outlet on EY generator would not function so it was replaced
By 1930 we were comfortable leaving the site.

Sat.
0800 Site was dark all buildings, generators, Vacuum system in good shape
1800 New switch at substation installed.

Sun.
0800 Site was dark all buildings, generators, Vacuum system in good shape
1200 Testing of switch complete (hicups included)
1300 Site power restored.
Facility cooling began.
converted Vacuum system to building power generators turned off.
1500 left for day.
Other Vacuum details by Vacuum group.