Wire size is based on the amperage of the connected load. Without that amperage an answer can not be given.
For a 30 amp breaker, you will need a wire that is at least 10 gauge in size.
6
For a dryer installation, you typically need a 10-gauge wire.
The wire size depends on the amperage, not the voltage. The fact that the welder runs on 440 volts does not affect the wire size! You need to ask this question instead: What size wire do you need for a three phase welder on an eight foot run if the nameplate amps are 45A?
Use AWG #6 wire.
For a 50 amp breaker, you will need a wire that is at least 6 gauge in size to safely handle the electrical load.
The size of wire you need for your electrical project depends on the amount of current the circuit will carry. Consult the National Electrical Code (NEC) or a qualified electrician to determine the appropriate wire size for your specific project.
You will need to use #8 wire.
You would need to use a wire size that is rated for at least 40 amps to be safe and to meet the requirements of the air conditioner. A common wire size for this application would be 8 AWG copper wire, which is rated for 40 amps.
For a 50 amp breaker, you would typically need a 6-gauge wire.
For a 30 watt mixer, you would typically need a wire size of at least 18 AWG (American Wire Gauge) for power cords and connections. This wire size can safely handle the current draw of a 30 watt device without overheating. It's always recommended to check the manufacturer's specifications for the mixer to ensure you are using the correct wire size.
Service entrance wire should be AWG #3 copper.