I have some new AC ducts in our new house that will soon be concealed behind new drywall, but before the drywall goes up, I wanted to run some conduit from the upper floor down to the basement for cable and network. Unfortunately, in the space between the two ducts (where I pretty much would have to put the cables, there is, attached to the floor joists a run of knob and tube wiring. I tested it with a voltage tester and it doesn't appear to be hot, so I'm assuming it's the neutral line (I can see where it's partner live line is, however). It looks to be in pretty good condition with the insulation in tact, but I'm leery about trying to run flexible aluminium condition right next to it. I have limited space to work in and limit options on securing it, but obviously I don't want the potential for the conduit to end up live!
How worried should I be about this? If I secure the conduit away from the k&t, would I be okay? Or should I just forget the conduit altogether and just drop (insulated) cables down the hole and hope I don't need to change them or add more at a later date?