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Massive Gauge Wiring

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  • Massive Gauge Wiring


    A quick question that has me intrigued.
    Why is the wiring in my home capable of powering my TV, digital set to box, stereo and dvd player all from power point (running off a power board) when it's only around 12 gauge wire(?) whereas when it comes to incar systems, everyone is using huge gauge wiring.

    Why is this? Is it because one is AC and the other DC?
    I installed my carpc into my pet Kangaroo, mate.

  • #2
    Voltage and resistance...

    when you're dealing with 120VAC... you can have 10 volts of voltage drop across your wire and not care... why? because you're pulling a minimal amount of amperage... 120VAC @ 10 amps = 1200 watts. 110VAC @ 10 amps = 1100 watts.

    With 12VDC, you can't tolerate much voltage drop due to resistance, because you're dealing with higher amperage. 12VDC @ 100 amps = 1200 watts. 11VDC @ 100 amps = 1100 watts.

    a 1 volt drop results in a 100 watt loss, whereas with 120VAC, it took 10 volts to equal that loss.

    in short, resistance is the enemy... thick wire is better
    '94 Honda Accord EX Sedan
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    • #3
      This is due to the fact that houses are 240 Volts (110 Volts in the states) and your TV and the like require less current to operate.

      Based on ohms law. Power (watts) = Volts x Amps.

      So if your TV uses 100 watts to operate, at 240V it would use .42 of an amp. If you power the same TV off 12V it would use 8.3 amps. Hence the need for larger cables to carry the extra current.

      Basically the higher the voltage, the less current is required for the same amount of power which equals smaller cables. This is why the auto industry is looking at going to 42 volts for cars in the future.

      AC or DC doesn't really make that much difference. Without going into the theory, AC is used for houses because it is easier to supply power over large distances this way.

      Hope that answers your question.
      Never let the truth get in the way of a good story