Dog, i spotted you earlier in a video, hope you don't mind me sharing it
I was wiring new offices for a railway company, they said 'class 1 ladders only, anti slip mat's, no ladders for working over 2M high, fall arrestors', so when fitting the lights in each office (2.2M ceiling height) we had to use a tower scaffold!!!! it wouldn't fit through the doors, so it was take into room, assemble, fit 1 light, dis-assemble, take out of room, take into next room, assemble, fit 1 light, dis-assemble, take out of room, repeat for 15 rooms!!!
then we saw the on site maintenance using an old wooden ladder that had been repaired and extended with bit's of 2x1!!!!
Dog, I've not installed any transformers, so I'm not sure over finer details. But some people think that RCD's are some kind or magical object and will save anybody in any circumstance!!!