These pics were taken after the tenant left this industrial rental, and things were being made ready for the new tenant.
In the first pic, please note the flex in the middle of the pic.
The next pic gives another view of the flex, from below.
This place had a 'mystery switch' in the middle of a wall; the flex went from the switch, across the room, to a 30A 240V receptacle high on the wall. I have no idea what it was for. There was no ground wire, either.
I can confirm Dnkldorf! I remeber like it was yesterday. The plan was to run some 3/4 conduit for an additional bc, there was NO room for any kind of raceway. It made for a long job, job security! You said it iwire! If...you can even lift the tiles up!
I have to go with DNK; that's not bad. The hospital in the Twp I work in is basically 'clean' above the ceilings, it's in a constant state of renovation!
As to the office bldgs, and comm, NOW, that's were the real MESS shows it's face. As I say....the sins of the past.