Rainy day in IL today. Thought I would try and replace our 20/40 submersible well pump pressure switch with a larger 30/50. I wired it just as the 20/40 was, put the correct pressure back in the tank and the power is surging when I turn it try to turn it back on. Thought maybe the wiring wasn't big enough for a 30/50, so I put the 20/40 pressure switch back on. Still surging. Any suggestions? I will leave the 20/40 until I can get an electrician here. No water for now though.

What do you mean by "the power is surging"?

This is how your wiring should look

http://www.catskillhouse.us/blog/wp-content/uploads/2007/12/well-pump-pressure-switch-wiring.jpg

Sounds more like a plumbing problem than an electrical problem. A 30/50 switch is not bigger than a 20/40 switch, just has different settings.

Error was probably in pressurizing tank.

Assuming you have a bladder type tank;

Turn off breaker to well.
Drain tank of all water.
Pressurize tank to 2 lbs. below switch cut in pressure.
That would be 18 lbs. for old switch, 28 lbs for new switch.
Turn on breaker.

Note: If switch is located on well pipe make sure pipe is clear and not blocked by debris. If switch has small tube from tank make sure it is clear.

Note: To insure that all water is out of tank, pressurize with a faucet open.