My husband has always wired a switch to break the neutral wire to turn a light on and off. I can remember for 40 years he has said to "break the neutral". However, our son worked as an electrician for 2 years and he said you always "break" the "power" wire (black one) Who is correct? Thank you!!
There was a time when switching the neutral was a common practice, but it was way more than 40 years ago. It's no longer permitted:
NEC 404.2(B) Grounded Conductors. Switches or circuit breakers shall not disconnect the grounded conductor of a circuit.
(In the case of your home, and in most cases, the neutral is grounded so the neutral wire is the grounded conductor.)
This way when receptacles, light switches, etc. are switched off, they do not carry any voltage to ground, making them safer for light bulb changing, etc.
Listen to the electrician. If you break the neutral, there is still power going to the fixture or the outlet, and if you contact a hot surface, you can get a serious shock.
Code requires breaking the hot (power) and always maintaining a connected neutral. (110 volt US systems)