Looks to me like V is potential and I is current
Yes, they're just the voltage and current coils in the meter.
Paul: in your diagram it shows the main switch opening the hot and neutural conductors, is this correct?
Yes, that's one of the many little differences between American and British practice. The main switch on a single-phase service here
always opens the neutral.
Just to make things interesting, however, on a 3-phase service the main is usually just triple pole and does
not break the neutral!
But double-pole isolation on single-phase circuits is used extensively here: The local isolation switches for an electric range, fixed water or room heater, etc. are normally all double-pole, breaking both hot & neutral.
