Isolating transformer

I'll show my different history here, but thinking back to the electrical engineering dept labs at Kings In London (basement of the strand palace), when things like transformers and AC motors and so forth were being taught, there was in effect un-isolated mains in  use on the bench with no special precautions, and in at least one  experiment  mains was present on 4mm screw terminals on a variac. I do recall a case in that experiment where one student got a bad shock, when the neutral "banana plug"  had come unplugged from his experiment. After that there was earnest debate about if the lab supplies needed to be fed via an RCD. In the end it was decided they did not, but isolator switches were fitted so the lab supervisors could then kill all the power to the students from a single point. That took place around 1990, so was well after the HASWA and so forth had got going. I was a postgrad at the time, and I was party to the discussions about what if anything needed changing, as like many others I augmented my income by demonstrating in the practical labs from time to time.  In many ways the labs and their equipment were a throwback to  decades previous, having had very little investment since the 1970s, but at the time you do not realise it unless you have been somewhere else as well to compare.

I'll show my different history here, but thinking back to the electrical engineering dept labs at Kings In London (basement of the strand palace), when things like transformers and AC motors and so forth were being taught, there was in effect un-isolated mains in  use on the bench with no special precautions, and in at least one  experiment  mains was present on 4mm screw terminals on a variac. I do recall a case in that experiment where one student got a bad shock, when the neutral "banana plug"  had come unplugged from his experiment. After that there was earnest debate about if the lab supplies needed to be fed via an RCD. In the end it was decided they did not, but isolator switches were fitted so the lab supervisors could then kill all the power to the students from a single point. That took place around 1990, so was well after the HASWA and so forth had got going. I was a postgrad at the time, and I was party to the discussions about what if anything needed changing, as like many others I augmented my income by demonstrating in the practical labs from time to time.  In many ways the labs and their equipment were a throwback to  decades previous, having had very little investment since the 1970s, but at the time you do not realise it unless you have been somewhere else as well to compare.