The house that i just bought is about 6 years old. I am planning to rig up all the sound systems to link together so that i can play the same music, from any of four different sources, throughout the whole house. What kind of wiring is best to use to transfer the audio signals? I am sending analog stereo signals that will connect at either end with RCA connectors. The wires will be going between rooms on the basement, first and second floors. Since there are no pre-existing conduits, I will probably have to route them through the basement and attic. I have found sources for long RCA cables (50ft+) but they are really expensive and I am not sure if they are shielded enough to protect the signal over such a long path through my walls. I figure that i can use better shielded wires of some sort and just attach RCA plugs to the ends, but I am not sure what wire to choose to get the most bang for my buck. Any suggestions on what to choose (and where to get the best deal buying it) would be most appreciated.

I am looking for the proper relay/switch/breaker that will allow me to turn my A/C system off with the signal from a 24v switch. The application is this: I have a moisture detection switch which will close a 24v circuit and I need that signal to break the normally closed circuit that supplies my central A/C. I've seen relays in the Smarthome catalog that do this sort of thing, but I would prefer a manual reset breaker--like a GFCI outlet--so that power would not be restored to the A/C even if the 24v circuit opened after a period of time. I'm having trouble finding this because I really don't know what such a device is called. Thanks for any suggestions. Jon