The nice thing about standards is there are so many <img src="images/graemlins/smile.gif" alt="" />

AC: Black = hot, white = neutral, green or bare usually ground, red usually for three way switches and such
DC: Black = ground, red = 12v unless its computers which then:
computers: black = ground, red = 5v, yellow = 12v, -5,-12,etc others
then network:
T568A : White/green,green/white,white/orange,blue/white,white/blue,orange/white,white/brown,brown/white
T568B : White/ornage,orange/white,white/green,blue/white,white/blue,green/white,white/brown,brown/white
then home phone: Tip = green, Red = green, line 2 black and yellow, line three blue and white
then business/telco 25 pair which I'm not going to bother to type out <img src="images/graemlins/smile.gif" alt="" />
EIA 561 rs232, etc standards, such fun <img src="images/graemlins/smile.gif" alt="" />