Mainly copper is used for household wiring but it may vary.
In North America the code book only recognizes #14 wire and larger for home wiring installations.
live wire,earth wire and neutral wire
no it will only decrease the current carrying capability
30 amps is often the limit recommended for standard residential wiring on a #10 copper wire. You are correct.
The ampacity or amp rating of all wire is rated by the size of the wire. NM (non-metallic sheathing) wire is no different. In household wiring 14 gauge wire must go on a 15 amp breaker/ 12 gauge goes on a 20 A and 10 gauge goes on a 30 Amp.
it will be printed on the wire
The most common sizes inside the house are: #14 for lighting #12 for receptacles #8 for range The most common for the service is a 4/0 aluminum (200 amp service) Pinky
This may sound like I think you are dumb, but I do not, I have been caught by each of these:Did you change the correct sensor? Both my cars and my truck have separate senders for the computer, the light and the gauge.Did you get the correct replacement part? An incorrect sensor can cause the gauge to: operate backwards, stick hot or cold, not operate at all. And to make this more fun the sender will look identical to the correct one except for the part number.Did you check the gauge while the sensor was unplugged? It should drop to cold when the sensor is unplugged. If not you have a bad gauge or a wiring fault, or both as a wiring fault can ruin the gauge.Final test, disconnect the gauge from the wiring at the gauge, does the needle drop? No then replace gauge. If does drop figure out where the incorrect indication is coming from.
no it will only decrease the current carrying capability
30 amps is often the limit recommended for standard residential wiring on a #10 copper wire. You are correct.
The ampacity or amp rating of all wire is rated by the size of the wire. NM (non-metallic sheathing) wire is no different. In household wiring 14 gauge wire must go on a 15 amp breaker/ 12 gauge goes on a 20 A and 10 gauge goes on a 30 Amp.
The gauge, wiring or sending unit is bad.
The correct GAUGE wire is 28 for a car stereo.
Fuel level sender (in tank) faulty. If replacement doesn't correct fault, check sender wiring back to instrument for poor connection. Finally, replace gauge.
Failed gauge, wiring, or level sensor.
Gauge is correct.
it will be printed on the wire
Bad gauge, bad sending unit, bad wiring.
The oil pressure could be dropping. Or, the sending unit could be going bad or have loose wiring. Check the wiring and the sending unit. It will take an oil pressure gauge to check that the pressure is correct.