This is determined by the size motor and the amount of amps the motor draws, be on the safe side and consult the owners manual or an Electrician.
The sizing of the breaker and feeder wire is based on the amperage of the compressor. Look on the name plate and find the amperage. The amperage on the nameplate then has to be multiplied by the motors full load amperage and that value is used for the wire size. Because the load is a motor the FLA is again multiplied by 250% to size the breaker. This takes into allowance the high starting current of a motor from 0 to 100% RPM.
Branch circuits are protected by the circuit breaker found in the electrical panel. Each circuit should have its one breaker. The breaker should be rated to protect the insulation of the wire, so you can determine the breaker size based on the circuit conductor size Example #14-2 should be protected by a 15 amp breaker
Depends on how many amps it pulls and the size of the wire in the circuit.
You use the correct size breaker depending on the size wire in the circuit. If the circuit is wired with AWG #12 wire use a 20 amp breaker. If it is wired with AWG #14 wire then use a 15 amp breaker.
A 15 amp dedicated circuit breaker should be used for the dishwasher. The disposal can be wired to the general kitchen 15 amp circuit.
The wire!! The breaker is there to protect the wiring not the device plugged into the circuit.
The size breaker you use is determined by the size wire used in the circuit. If you use AWG #12/2 wire then use a 20 amp breaker. If you use AWG # 14/2 then use a 15 amp breaker.
A circuit breaker protects the wires that the devices are connected to. If the devices that are connected to the circuit are 20 amps the wire size should be #12 wire fed from a 20 amp breaker. This breaker should not trip unless the circuit is overloaded or a fault occurs on the circuit. If the devices that are connected to the circuit are15 amps the wire size should be #14 wire fed from a15 amp breaker. This breaker should not trip unless the circuit is overloaded or a fault occurs on the circuit. Putting 20 amp sockets on this 15 amp circuit will work but the circuit is limited to the amount of load that can be plugged in. You will not get the full capacity of the 20 socket because the breaker will trip at 15 amps.
The sizing of the circuit breaker and hence the wire size to feed the pump are all dependant upon the amperage of the pump. This question can not be answered without that information.
If you have to ask here, you shouldn't be trying to wire in a 20A compressor. You will require a special circuit for the voltage and current with an independent breaker. Check your local code for the wire size or talk to a qualified electrician.