When you lose a phase on a three phase system it is referred to as single phasing.
I have never seen 2 phase myself but I was wondering since you mentioned it went off line in 1981 why the nec still lists it for motor loads. If it's no longer used it would be nice if they removed all reference in the code to two phase.I think the last North American two phase generation went offline about 1981, so it's hardly worth discussion. It's a horse of another color.
is two hot lines out of a three phase system called 2 phase?
any info will be apreciated:laughing: