Why does a CCFL in an LCD have a bigger pink lead and a small white lead?
It's because the pink wire is at a high potential with respect to the rest of the system. The distance between two conductors at which bad things start happening is related to the potential difference between them, so the thicker insulation is to force the conductor to stay further away. The ground wire doesn't need it because it's at the same potential as most of the things it could come near, and only a few volts away from the rest.