What happens if a phase and neutral of a single-phase energy meter is reversed?

What happens if a phase and neutral of a single-phase energy meter is reversed?

Nothing will happen. the single phase current means alternating current which changes its polarity 50 times per second (frequency), not like direct current DC having fixed polarities of positive and negative all the time . if the polarity of a single phase motor is changed , the motor remain runs in its same direction , but DC motor will reverse its running direction when its polarity changed. same thing will happen in ac energy meter.

Swapping phase and neutral would have no effect whatever, the meter would continue to operate normally.

Exchanging the line and load connections (input and output) would reverse the meter and it would run backwards. Unless it had an anti reverse pawl in which case it wouldn't move.

Nothing,as far as the meter is concerned..it will operate as normal, but unless the error is detected, the wiring to the remainder of the premises would be in a dangerous state.