No! The minimum wire size allowable is 10 gauge for a 30 amp circuit. Don't risk the chance of an inner wall fire because too small of a wire gauge was used. Never shortcut anything to do with electrical wiring. Never.
Yes, a #8 wire is rated at 45 amps. One of the duties of a breaker is to protect the wire from over current. A 30 amp breaker will trip before reaching 45 amps so the wire will never get close to its rating.
A breaker is used to protect the conductor that is connected to it. A #14 copper conductor with an insulation factor of 90 degrees C is rated at 15 amps. So you see in this situation, the breaker is too large to protect the size of wire that you stated.
There is one occasion where the breaker can be larger than the wire size capacity. That is on motor load connections. A motor on start up can draw 300% of its nameplate amperage rating. To stop needless tripping every time the motor start, the electrical code allows a breaker to be rated at 250 % of the motors name plate rating..
For example if a motor draws 10 amp running current, the proper size breaker will be 10 x 250% = 25 amps. As there is no wire rated for 25 amps the next largest size would be #10. A #10 copper conductor with an insulation factor of 90 degrees C is rated at 30 amps.
12 gauge wire is required to be protected with a 20 amp max breaker. 10 gauge is required for a 30 amp breaker.
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.
Look on the heater and see what amps it is pulling. That will determine the wire size and breaker size. It must be on a dedicated circuit. 15 amps = AWG # 14 wire with 15 amp breaker 20 amps = AWG # 12 wire with 20 amp breaker 30 amps = AWG # 10 wire with 30 amp breaker 40 amps = AWG # 8 wire with 40 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.
You need a 60 amp breaker.
Depends on the wire size used in the circuit. If you use AWG # 14 wire you must use a 15 amp breaker. If it is wired with AWG # 12 wire then you use a 20 amp breaker. If a AWG # 10 wire is used then a 30 amp breaker is required. The breaker protects the wiring from overheating so you must use the proper size breaker for the wire used.
25 amp breaker
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.
30 amp breaker with #10 gauge copper wire
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.
50 amp breaker wired with AWG # 6 wire.
For typical residential house wiring 12 AWG wire is required for a 20 Amp breaker. If you change out the breaker for a 25 A breaker you would have to rewire the circuit with 10 AWG. In that case you could up the breaker to 30 Amps. All outlets and switches should be rated at the same voltage and current as the breaker.
Use 15 amp breaker with 14 gage wire or 20 amp breaker with 12 gage wire. Either way will work just fine.
Look on the heater and see what amps it is pulling. That will determine the wire size and breaker size. It must be on a dedicated circuit. 15 amps = AWG # 14 wire with 15 amp breaker 20 amps = AWG # 12 wire with 20 amp breaker 30 amps = AWG # 10 wire with 30 amp breaker 40 amps = AWG # 8 wire with 40 amp breaker
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.
You need a 60 amp breaker.
Depends on the wire size used in the circuit. If you use AWG # 14 wire you must use a 15 amp breaker. If it is wired with AWG # 12 wire then you use a 20 amp breaker. If a AWG # 10 wire is used then a 30 amp breaker is required. The breaker protects the wiring from overheating so you must use the proper size breaker for the wire used.