Originally Posted by mulveyr

No, you don't need an overvoltage protector with any modern hub dynamo and LED lights. The headlight you selected is a halogen - you would be MUCH better off with a decent LED light like the IQ Cyo, as you'll never have to worry about a bulb burning out. You should also get lights with standlights so that they still illuminate even when you're stopped at an intersection, etc.

The wiring goes from the hub to the front light, and then from the front light to the taillight. The particular headlight you chose is not switched. Some models do have switches, some don't. It will tell you in the specifications.