>4 inches is the usual for parallel runs

here are some answers for you. you should always keep the a/c as far away as possible from your voice and data lines. the a/c should be in some sort of conduit or greenfield (flexible conduit) you should try and run the voice and data thru some sort of conduit also. you can run them together. as long as the a/c is in conduit, you can place the voice and data outlet next to it, but they should really go on each side of the stud if possible. you should also place both voice and data in the same outlet/ faceplate. a/c will effect both voice and data lines if run too close.

220V can be an issue, and running parallel could be a problem, even at 6-8".  The >4" chicagoan mentioned is, I beleive, for parallel to a 110-120V AC run.  The higher voltage of the 220V run will produce more EM than a 110V run will, requiring greater distance.

I looked this up, once, not long ago, and I seem to recall something about 1-2 feet for a parallel run, if you want to ensure Cat5 compliance with UTP.

So, I guess it depends on how many kVA you push through your line, and whether the line is in a grounded conduit (which would include a Greenfield.) and how many lines are within that proximity,i.e. if there are 6 power-runs of 110V, with a combination of conduit and non-conduit, they all figure into the recommended distance for a parallel communications cable.

i have a relevant question, if you have to make a cable close or tight to power line, STP would be helpful? personally, i dont think so, but not sure.

It really depends on how close, and for how long.  I don't think STP has all that much EM protection over UTP and costs a bunch more.  If the parallel run is only for a few feet, it shouldn't hurt too much, in my experience.

i think so, but no evidence information. i am not sure if chicagoan still can provide similar vendor's official information about it, thanks in advance.

If it must be close, run it in a conduit to be sure.

that really depends on what kind of conduit, if it is plastic ones, ... ;-))

Ok, then.  A grounded metal conduit.

sure.

STP is problematic from a termination standpoint and AFAIK there's no CAT5E or CAT6 STP to be had yet.
Fiber or pipe for a really bad environment.