It was in no way connected to the building. How is it premise wiring? This is on the load side of the power plug of a U/L listed appliance. I got that same answer when I asked about other things they did that wouldn't meet NEC muster. It is like the 14ga wires inside a 50a range.
I bet on these studio setups they do the same thing. There is a power plug that feeds a U/L listed "appliance" and that feeds the amps and such.
I agree it would be easier to accept if it wasn't a 5-15 socket.
I suppose IBM would also say this was under the covers and unqualified people were not supposed to be using it.
I also do not see the hazard of not being grounded. This isolation transformer idea is also a very common thing on lab bench power supplies. They say it is safer, The first ground fault is free.
