I have seen the potential coil go across two phases to measure voltage. But there is no neutral attached to the potential coil. If the two lines were 120v ea. the potential coil will have 240v of potential going across it. How is it that this coil can measure the voltage in both phases/lines without a return path? Like a complete circuit that needs a way back to the source. Or is it that the two phases of the lines are 180 degrees apart and it will use the -180 as a return? Or am I confusing that potential coils don't need to return any current? I'm not sure if current has to travel along potential coils. Wouldn't a tiny amount of current be necessary? I see phase to phase transformers and it makes me wonder how a transformer can have a phase connected to each side of the primary without the need of a neutral. Is this also because of the 180 degree phase shift? Thanks in advance for any explanations.