I believe that the wires supplying a 30 amp circuit must be at least 10 gauge. If you have 14 or 12 gauge wires going to or from your 15 amp breaker, then drawing 30 amps over it could cause a fire hazard. It's like using those cheapo non-UL certified extension cords to plug a MILLION X-mas lights into (drawing more power than the wires can handle). You also have to make sure this GFI outlet you refered to is rated for 30 amps.
Do not simply swap out breakers. Overloading the wires in the circuit protected by that breaker will cause a fire.
If you need a 30 amp circuit you must run #10 gauge wire.
To be short...Yes
You could. However, it will trip at 15 amps, so be sure your load is less than that. Continuous draw should be no more than 12 amps.
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.
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.
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.
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.
A 2 pole 30A circuit breaker is a device that is used to supply a 240 volt power source for a device that operates on 240 volts and under 30 amps of current draw
generally, an electric range will use either a 30A circuit or a 40A circuit. Check the requirements of the range.
A double pole 30 amp breaker can pass 30 amps per pole, therefore #10 wire should be used.
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.
Yes, you just have to be sure you are grabbing power from each of the two legs.
No, you're fine. Breakers are mainly used to protect the wires (and people), not the appliance. The appliance should have its own overcurrent protection (a fuse usually). The 30 amp breaker will work in this case. First off, dryer outlets are usually 30A as a standard, just like normal wall outlets are 15A. Secondly, you want your expected load to be 80% of your breaker size. So, a 20A load would call for a minimum 25A breaker, they just rounded up to the standard 30A breaker. (Which has a maximum expected load, by this rule, of 24A.) Good question though.