Using MCA ( minimum circuit amperage) to select wire type and gauge

I was wondering if anyone knows how to determine MCA ( minimum circuit amperage) to so that you know what wire type and gauge to use for things e.g motors etc.

I think that if you have a panel you are supposed to take 125% of the largest motor amperage and then add that will the remaining amperage to find what the MCA is this a true statement?

Also is there a rule of thumb when finding the MCA for field devices like motors and VFD's or am I completely wrong and there is a different process to finding what type and gauge to use?

I think you must mean Maximum Circuit Amperage - Also called Full Load Current or Amperage.

There'd be a whole lot of troubles if you chose cable sizes based on the Minimum current.

There is some good information regarding minimum allowable wire size here: http://www.electrician2.com/calculators/wireocpd_ver_1.html