Info on electricals for AV systems for your home.

[Fantastic]

The following link is a pdf download about electrical wiring for your home with specific reference to your AV system. It's written professionally and so should clear all your doubts. I have not gone through it yet but will do so later on. Appears to be good. Gets a bit intense as it progresses. Beginners beware !
Refers only to US power lines (110V). But that isn't an issue. Lots of references at the end.

http://www.exactpower.com/elite/assets/pdfs/theTRUTH.pdf