This stuff has no ground wire at all. There are lots of places around here where there are plastic insulated wires with no grounds. When did the code start requiring grounds? I helped my Dad wire our new house in the early 70's and all that wire had grounds.
Another question. What does NEC say about using a 12-3 w G to run two separate circuits assuming the red and black are on two separate single pole breakers? I have seen it done and have read conflicting things about whether or not it is allowed. I would think there is a potential to overload the neutral. On the project I just finished, as I mentioned, someone had two separate circuits tied to a 30 amp double pole breaker with a 10-3 cable. I replaced that wire with two 12-2 w G wires on two 20 amp single pole breakers. I know the original setup was a no no. If one circuit saw an overload would that breaker have tripped? My guess is probably but certainly not a good scenario.