I am building a home theatre and incorporating a central computer so I can watch my tv shows that I have got stored on my computer's hard drive. I have a non internet connected router which has wifi and 4 ethernet ports. ethernet port 3 is the central computer, ethernet port 1 is for apple tv box, ethernet port 2 is for xbox and ethernet port 4 is for the PS3. What I would like to know is that can I run the ethernet cable for the apple tv box next to 13 amp power supply (4 gang extension lead) which is supply a FM signal amplifier the signal amplifer is 3 amp or would it cause interference.
It is very rare to get any interference from power on ethernet cable. I suppose if you wrapped it around a big transformer it might. If the current is DC then there is close to zero issue. AC power would have to generate a large enough field to cause currents in the ethernet.
The only time I have ever seen a issue was when someone ran one though the enclosures for florescent ceiling lights and that would only cause a issue when it was first turned on.
You best bet is to try it as see what happens because you only fix is to run shielded cable and to actually work correctly you must ground the shield on both ends. Since almost no consumer equipment has this ability to you need a small patch panel at each end. Telco equipment uses this and they use special rj45 ends that have metal in the sides that allow you to connect to corresponding grounds in the sides of the jack in the equipment.