(mostly copying a PM I had with @Jon )
Pearl and Tarkin are now in the classroom awaiting power, while Blue and Red are not moved but probably will move later. There is a hole ripped in the wall to the bay door alcove where the blowers and outlet vent bezel (“knee wall”) will sit, we’re not doing roof penetrations at this point. Air compressors can go here, but chillers probably cannot.
It is possible to put the chillers on the other side of the wall in “coworking”, but this will be noisy.
There is not currently any doorway left to keep dust out of the (laser) classroom or lounge.
There is ample panel amps capacity in the lounge panel. It is full of breakers but many are unused. There are a couple of unused 100A 3ph breakers. Those are oversized, so one can be replaced with a 30A 3ph breaker for Tarkin (I have one, it is sitting on top of Tarkin). Pearl can use a 20A 3ph (I don’t have), or a single phase but it might need to be 30A. I think we need to be forward-thinking and just make it all 10AWG 3 phase.
The one exception in that Blue (not in the laser room yet) is 120VAC (20a circuit is fine), so it requires a neutral. It might be capable of 208V operation I’d have to check.
In the past we ran power for the blowers through power-bearing wiring through switches near the lasers then off to the blowers in the alcove. That’s not essential, and a significant PITA for a number of reasons. Pearl and Tarkin’s controllers have relay outputs for turning on the blower while running jobs. The relay could switch the power to the blower at the machine and run flex for the blower’s power from there to the alcove, but it may make more sense to run power to the alcove and only low-voltage relay control lines from the machines to switch power with relays inside the alcove.
Looking at the numbers, I’d say another 3ph 30A circuit would be needed, running from the panel to the alcove. However, for this one, a neutral is needed. Armorlite MC flex comes in 10/3 + ground but it needs to be 10/4+g. The neutral will probably have green insulation inside the flex. Is it legit to retask the 10/3’s ground as the neutral and then get ground from another wire not inside the flex? Ground wires aren’t current-bearing and in some scenarios just go to a cold water pipe. I was thinking more of it being wire nutted to a ground from the nearest outlet.
Electrically, this should be fine, it’s a matter of whether code allows it. This does mean we have more than 3 current-bearing conductors in the flex. It might be required to still be in a metal-clad envelope, which might still be easier to run as flex from the nearest box instead of trying to get a whole 10/4+g run which might have to be rigid conduit.