Those old auto plants must be a real challenge with all that "made it up as we went along" stuff.
Sometimes it gets more challenging when one has to figure out "is this on the DC system or the AC system". Great, figured it out to be AC. Next = "Hmmm. The wye or the delta system?". And sometimes 2-phase (90 degree shift) is still active when they have their own steam generating plant..
Detroit used to be exclusively DC. When AC was installed, many loads remained DC with in-house rectifiers or steam powered generators. (Parts of Detroit have central steam that one can purchase for heating, cooling or generating electricity.) Elevators are commonly left as DC, as are stage lifts in old theaters.
I sure wasn't complaining about the old buildings. It is a total blast to explore and find cool stuff.
My favorite "accidental find" is the bus bars in the Ford Model T plant on Piquette Street, now a museum. The first time I worked in there I noticed long, super shiny, large diameter brass rods running along the ceiling of each floor. I didn't pay much attention. At one point I brought in a 20' ladder. The manager told me "Watch out for those brass rods. They are live.". Sure enough- They use them to this day.
An other favorite find were the tunnels below Ford Motor Company's Product Development Center. They go for miles. think they even go to the Rouge Plant and Power House.
If you ever visit Detroit & like old cars, be sure to check out the Model T museum.
https://www.fordpiquetteplant.org/
Greenfield Village & Henry Ford Museum are also a fun way to spend a few days- or more. (They aren't auto museums. Just cool everything).
https://www.thehenryford.org/visit/s. Working projects in the museum is really fun, as one could expect.