flickering lights

A person called me today to say that there lights are dimming or flickering and when they use the toaster or microwave they are half power. Or could there be a fluctuation in voltage from the source ( Hydro )

Could this be a loose neutral in the main panel.

Your interest is delightfully appreciated

The main service neutral was never tightened down
Didn’t appear to be any arcing around lug

All is well.

Mark

thanks for the happy ending it feels good to hear of one every once in a while