Isolation transformers do not have a grounded secondary as a general rule. That is the point. IBM used them for the convenience outlets in all of our old mainframe machines. The secondary was completely floating. That actually accomplished 2 things. We never brought a grounded conductor into the computer room panels so that was the only way to get 120v and it also prevented electrocution or overcurrent in any line to ground contact ... at least the first one anyway. The cases of connected equipment still got grounded via the EGC. Usually the line filters in the first piece of plugged in equipment stabilized the voltage at +/- 60v. We tried to keep the customes out of there but an available NEMA 5-15 will get used.
