I am doing some rework in a system that has a combination on conduit and bx cable. The bx drops to light fixtures from junction boxes. In looking at new bx cable, I find that two types are available. Some has a light, bare aluminum (?) wire as perhaps some type of ground. For 12-2 bx, there are 2 insulated conductors and this little wire bundled in the package. Other 12-2 bx cable has a fully insulated, full size ground bundled with it. Most of what I see in the home center electrical section is like the latter. The other has a special, lower price and is being discontinued. Did Code requirements change? The existing structure bx (or conduit) wiring has no ground wire and obviously relied on the bx shield as the ground. Which wire should I buy? When putting into the old system, should the ground wire be terminated in the box (connected to conduit) with grounding screw, and then ground the box like is done with Romex? What are the requirements for rework on the existing system.