"How many amps can a 6 gauge wire 12v dc carry?"
It all depends. There are several factors. Probably the most important would be the expected length of the wire one way only. Others would include the type of wire insulation it has and the highest expected ambient temperature that the wire will be exposed to.
For example: AWG. #6 THHN copper is rated for 0 to 600 volts (ac or dc) and typically rated for 60 amps BUT! There are several "derating" factor to consider. The biggest one being voltage drop when dealing with low voltage direct currents. AWG. #6 THHN copper at 75*C wire with one set + and - in a steel conduit can carry 60 amps over a 10 foot long wire with a 5% voltage drop. So if you started out with 12.6 volts you'd end up with 11.97 volts or less.
By comparison, using that same scenario but using 120 vac, it could carry 60 amps, 100 foot with a 5% voltage drop which leave you 115 volts which is no big deal BUT!, it is a big deal to lose almost a whole volt at 12 vdc nominal.
Remember - Ohm's law - For a given wattage, if the volts change, the amps change and inversely, if either the volts or amps change, the wattage changes. A lot can depend on the type of load as well. Lights might burn dimmer. motors would run slower, a heater would put out less heat and so on and so forth. Or just not work at all.
A #6 AWG copper wire with 60 degree Celsius insulation rating can carry 55 amps, 75 degree Celsius insulation rating can carry 65 amps, and a 90 degree Celsius insulation rating can carry 75 amps. If it is aluminum or copper-clad aluminum the ampacity for the three temperature ratings would be 40, 50, and 60 respectively.
A #6 copper wire with an insulation rating of 90 degree C is rated at 65 amps.
60
You are probably thinking about 1/0 wire (1 ought wire). In copper it is rated at 175 amps and in aluminum 125 amps.
According to NEC, it's max rating in free air is 18 amps.
70 amps.
A #8 copper wire with an insulation rating of 90 degrees C is rated at 45 amps.
18 amps.
The amps that a four gauge wire will handle will depend with the thickness of the wire. If the wire is thin, the four gauge will handle 95 amps.
You are probably thinking about 1/0 wire (1 ought wire). In copper it is rated at 175 amps and in aluminum 125 amps.
10 guage
34.539 miliamps is only 0.034539 amps. A 16 gauge wire will handle that.
According to NEC, it's max rating in free air is 18 amps.
140 AMPS
70 amps.
101 amps for chassis wiring and 37 amps for power transmission. This is for short lengths of wire.
the gauge of the wire determines how much amperage a wire can carry the insulation determines how much voltage the wire can handle
A #8 copper wire with an insulation rating of 90 degrees C is rated at 45 amps.
18 amps.
10 gauge wire will only run up to 30 amps