After removing the dead CCFLs from an LCD monitor, I noticed something odd. Although both wires go to different ends of the tube and presumably carry identical currents, they are visibly and internally different sizes. Everything I know about electronics tells me the current is the same in all parts of a circuit for a series circuit, but this defies that!
See picture attached.
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.
I guess ground wire does not need thick insulation. So every penny saved :-)
