Yes, if he puts a four wire receptacle in, there must be four wires back to the panel. You can probably legally retrain the three wire circuit for the range, but if you're doing substantial work (including pulling additional other circuits, you might as well do it right.

Thank you! Yes,I am doing additional work (additional circuits and moving outlets) so I will just add this to the list.

Abbey

any particular reason you are changing it? Your new range might work just fine with it.

Hi weedmeister,
Well the reason I am changing it is because I am paranoid about electricity due to a house fire as a kid. Seeing your house go up in flames can have a long term effect on a kid!
So in the interests of improving range safety (at least in my own mind lol) I am going with the 4 wire outlet which will be
properly grounded (as opposed to the 3 wire, which means it is grounded to the stove chassis I believe?). It probably won't make the range any safer, but it will make me feel better so I am going to have it done.

Abbey

Three is no real safety difference between a 3-wire and 4-wire range or dryer circuit from a fire standpoint.

The advantage is the redundant safety ground.

The minor voltage rise on the chassis from 120 V loads on the circuit and the voltage drop on the shared ground-neutral is not a fire issue.

Under very specific (and uncommon) circumstances it could be a hazard to people.

Some newer stoves have enough electronics they can benefit form having a separate grounding conductor to reduce electrical noise.