Question makes no sense, but anyone would probably need to know the rating (watts) of the lights to give an answer.
Depends on the wire size you are using. If the generator breaker is a 30 amp then install a 30 amp breaker.
Depends on the size of the wire going to the A/C. If the wire is AWG #10 you cannot install a 40 amp breaker. If the wire is AWG #8 you can.
Not unless you change the wiring for that circuit. The breaker protects the wiring and if you install a 40 amp breaker on a 15 amp wire circuit you will have a fire in your home.
The pool light is usually on a 15 amp circuit. The breaker feeding this circuit must have a GFCI rating.
Minimum size is 10 gauge with a 30 amp breaker. To be safe I would install an 8 gauge with a 40 amp breaker.
Cant you need a amp or you will blow the battery
Yes, in home wiring as long as it is protected by a 15 amp breaker. Remember this circuit will only handle 1800 watts and cannot be loaded to any more than 1440 watts. So if each light is 75 watts then the maximum you can install is 19.
The breaker will have a black wire connected to it. Turn off the main breaker and then disconnect that black wire from the breaker. The breaker will snap into the main bar. Remove the breaker and install the new one. Reconnect the black wire to the breaker and then install the cover and turn the main breaker back on.
No, you should not install a 30 amp circuit breaker to a machine which normally requires a 20 amp supply. The circuit breaker is protecting the wire to the machine. That wire is likely only rated for 20 amps, (# 12 awg). Therefore, a 30 amp breaker could allow too much current to go through the wiring to the machine and cause the wire to burn down. Replace the 3 phase 20 amp breaker with the same amperage breaker.
50 amp breaker.
You need a breaker rated for 10 amps and 250 volts. The breaker must also fit properly in your panel.
Normally older ovens required a AWG #8 wire on a 40 amp breaker. On a modern double oven I would recommend you install AWG #6 on a 50 amp breaker. That way you are safe and will not have to worry about the breaker tripping. It will cost a little more but is worth it in the long run.