What causes neutral at a switch to become hot?

Is the neutral hooked up to the switch?if so it's being backfed somewhere to be used as a hot feed. Which is allowed as long as its reidentified as a hot wire.

Is the neutral hooked up to the switch?if so it's being backfed somewhere to be used as a hot feed. Which is allowed as long as its reidentified as a hot wire.
In which case it is not a neutral, but simply a white wire.

If this is what you mean liane then it could be something a simple as a loose connection.

Are you referring to electrically charged "hot" or hot to the touch?

Sounds like it's being used as a switch leg. I.E. black hot to switch,then white to light for power. Does it become hot only with the switch in the "on" position? If this is the case, it is not a neutral at all.