Dynamo Hub Wiring
 

I've seen some dynamo hub where there is earth or negative sign indicating ground side of the connector, I have PV-8 dynamo and the connector doesn't indicate which one is positive or negative, the pdf instruction does't indicate that either, Does anyone know if this dynamo hub has specific postive and negative side at the connector? or can it be wired either way?

SP hubs can be wired either way. It produces AC so there is no + or -, but for some reason some manufacturers have indicated that there was a plus or minus.

Shimano hubs are grounded to the fork, so that is an issue with a Shimano hub if the light is also grounded to the fork (I wasted hours learning about that). But your SP is not grounded to the fork, so does not matter.

I think the reason that some manufacturers had a + and - was because that is a way to figure out how to wire things if components are grounded to the fork or frame.

Thank you for the explanation.