The difference is, it's cheaper to make a switch with a 20A rating for purely resistive loads, but switching an inductive load like a motor means the switch must be capable of interrupting and extinguishing the arc that forms as the inductor tries to keep the current flowing. But just saying "Commercial grade" "Industrial grade" or even "Spec grade" does not necessarily mean you get that motor rating, you must look for it to be explicitly stated on the switch or the spec sheet. For example Leviton Spec Grade 20A toggle, yes, it's rated for up to 1HP. P&S / LeGrand Spec Grade 20A toggle, no HP rating at all.
Yes. We would differentiate them as AC1 (pf > 0.96) and AC3 typically for induction motors.
From Schneider:
AC-1 category
This applies to all AC devices (loads) with a power factor of at least 0.95 (cos phi greater than or equal to 0.95).
Example of use: resistive load, heating, distribution.
AC-3 category
This applies to squirrel cage motors where breaking occurs while the motor is running.
Example of use: all squirrel cage motors, lifts, escalators, conveyors, bucket elevators, compressors, pumps, mixers, air conditioning units, etc.
The AC3 current rating is less/very much less than than the AC1 rating for the same device.
