You can, but be advised that whatever you plug into the new outlet should not exceed 5000W capacity (20A x 250V = 5000W)or you could risk overheating the new outlet with serious results. To prevent this, you should make sure the circuit breaker is a 20A also.
An existing outlet can be converted by replacing the 30A circuit breakers or fuses in the circuit breaker or fuse box with 15A breakers or fuses. The 30A outlet should also be replaced by a 15A outlet. This is all that is required if the wire from the supply to the outlet is 10, 12, or 14 guage. The existing wire should be 10 guage wire to handle the 30A and there will be no problem in the same wire providing the 15A.
You have to replace the wire (as you are increasing the current capacity), the outlet, and the breaker. Essentially you have to remove the old circuit and put in a new one. You can't reuse parts of the old circuit as you are increasing the current capacity and they would be underrated.
Yes it will operate it fine.
A two pole 20A circuit breaker can be used for any 240V load that requires 20A, with supply conductors no smaller than 12AWG. Since a clothes dryer typically requires 30A, and a range 40A to 50A, a 20A 240V circuit could probably be a window air conditioner, pool pump, or some other 20A 240V load.
It would have to be a 30 amp breaker to use the full power of the welder. I'd say go with the 30A. The general rule is that your planned load should only be 80% of the circuit capacity. That means a 30A circuit should have a maximum load of of (30*0.8) = 24A. With the 30 amp breaker you must have at least #10 wires feeding the circuit.
Assuming a 120V circuit then a 30A Single Pole. For a 240V circuit an 30A two pole. Of course anything smaller that a 30A is acceptable. 30A is the maximum allowed.
The fuse diagram for my 91 Capri is as fallows: Engine 15A Stop 20A Power Window 30A \ Meter 10A Hazard 15A ------ HTD B-light 20A Cigar 15A Tail 15A IG Relay Room 10A door lock 30A Audio 15A \ Fog Lamp 20A Air Cond 15A ----- \ Cooling Fan 20A Wiper 20A Heater 30A The IG Relay and the Heater are the big ones on the side of the fuse box.
10/3 with ground NM.
no
10 AWG.
Yes and no. You can't put a 30A outlet on a 50A breaker as it will be a fire hazard. You can put a 50A outlet on it safely. Then you can plug the 30A load into it, but this is unwise and can be dangerous if you don't put fuses in your pigtail adapter. The best solution: Go ahead and install your 30A outlet but replace the 50A breaker with a 30A breaker. This is the safest and cleanest solution.
Two pole (for 240V), 30A typical.