Re: Improbable - disagree
We let the smoke out of a bunch of lab equipment, many times. I was working at a company that supplied equipment for airplanes, which run at 120V, 400 Hz, and we would have to run our checks from a PC connected by a serial line (120V 60Hz).
To save money on the 400 Hz system they did not tie the grounds together, and you can imagine what happened. Plug the device under test into 120V 400Hz, then connect the serial port to the device, and nothing would work. Blown serial port. We got really good a replacing plug-in serial boards, because we blew them out so often. Maybe once or twice we would blow a power supply, or in those days pop a fuse. the one 400 Hz power outlet gained a huge note "FLOATING GROUND".