I have been doing some research on this question. The answer I get most of the time is that this is for safety reasons. That there can be no current in the neutral that didn't come from the live. If anyone has a clear answer, please tell me.
- Electronic – Why is there a potential difference between neutral and ground (earth)
- Electrical – How to calculate the neutral wire size of a home (department)
- Electronic – Why an electrician wiring error could make a PC’s USB shield be at 120V when it should be grounded
- Electronic – Is an ungrounded earth wire worse than no earth wire
- Electronic – If ground and neutral are bonded at main panel, why aren’t all grounded device chassis energized
- Electronic – Figuring out ground in AC circuit