What kind of wire should you run?

For wire that's going to be in a wall the wire needs to be fire rated. This is how flammable the cable jacket is and how toxic the smoke it releases when it burns is. In order of fire worthiness from least to most you have:

  1. CL2
  2. CL3
  3. CL3 Riser Rated
  4. Plenum Rated
The difference between CL2 and CL3 is negligible and relates more to it's voltage carrying capacity than to the jackets fire worthiness. Both CL2 and CL3 are allowed to be run through the walls or ceiling of a room. CL3R, or Riser rated, is required when the cable goes between floors. In practice, it's very hard to find riser rated coax, and most people just run regular CL3. Plenum rated wire is rated for running in an air space, like an air duct or an elevator shaft. The jacket is frequently made of Teflon and regardless what it's made of the jacket generates very little smoke when it burns.

I ran 2 Cat-5e's and 1 coax to a jack in just about every room. For rooms with speakers, I also ran a pair of speaker wires from my equipment closet in the basement to the location of the speakers, and a single Cat-5 from the equipment closet to the location of the keypad to control the speakers.

Running the Wire

When you're running your low voltage wire, you should not run it right next to AC power since that has the potential to cause interference from the AC in the low voltage wire. You can run it parallel if you just run it a foot or so away from the AC line. It is acceptable to cross AC power lines as long as you do so at a 90 degree angle.

Running wire in already existing construction where the walls are not open can be very challenging. Get an ultrasonic stud finder and a measuring tape and start looking at the walls of your house. You want a wall that runs continuously between the two places you need to go, preferably an interior wall that doesn't have any insulation in it, or if you have an old house you may find exterior walls that don't have any insulation in them. Use your stud finder to figure out where the studs are. Measure on every floor that wall is going through to make sure it doesn't hit a window or door frame, and then, when you're really sure, you can start cutting out a small section of drywall and drilling through your floors. Get someone to help you shine a flashlight through your holes to see if you got it right. If you did, then you can use fishtape, string with a weight on it, coat hangers or whatever else your imagination can dream up to help you pull the wire between floors. If you think of it like a puzzle, it's kind of fun. On the negative side, if you screw up, you'll get to do a lot of plaster patching.

New construction? Piece of cake. Run your wire. Drill holls through studs if necessary to run your wire. Use nailing plates so the drywall guys don't nail into your wire.