Hello all. Just a question about 220V wiring for you. I've encountered
several 3-conductor 220V circuits recently. Doing a little research, I
see that around 1965 or so it was changed to requiring 4-conductor to
seperate the ground and neutral (vs. the old two hots and the third wire
being both the ground and the neutral).

Am I correct in the above? (may only be residential NEC stuff).

Does anyone know if having the neutral and ground share a conductor is a
bad thing? Does having a seperate ground really help with safety? Is
some equipment effected by the N/G binding, or a seperate N and G?

Thanks in advance!!

Chris