Hello Steve;
Back in 1996 I spent three weeks in London loading in and setting up the first full blown production of the musical 'Tommy', we built the show in our shop here in Canada, one of the colonies.
One thing that really surprised me was how you distributed three phase to the dimmer racks in the West End; all FOH dimmers were from a phase, all dimmers supplying flown electrics were from a different phase and all dimmers supplying deck level circuits were from the third phase. The explanation I was given was this minimized chances of anyone getting shocked by anything greater than 240 volts, 415 volts for example.
Thanks for the memories.
Toodleoo!
Ron Hebbard