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<blockquote data-quote="McIntosh" data-source="post: 6151485" data-attributes="member: 605496"><p>Your basic understanding is quite good, to a point. A wire&#039;s capacity is an ampere rating, not a power (watt) rating. Yes you can get ten times the power through the same wire at 120 volts versus 12 volts (Ohm&#039;s law P=IE). AC to DC is not apples to oranges by any means, the same laws apply. Given a load (amperes), a wire size and a wire length the voltage drop is the same (for all intents and purposes) whether its 12VDC or 480VAC. There is a difference that matters. Losing 2 volts on a 12V system has a tad more impact than losing 2 volts on a 480V system. Combine that with the fact you need ten times the current to achieve the same power level (120V versus 12V) and the required wire size goes up dramatically. I generally don&#039;t work residential, mainly commercial and industrial. Electric ranges, dryers and AC are usually #8 or #6 BTW. Nothing smaller than #14 is allowed in a home (#12 for kitchen, bath and dining room circuits). The largest low voltage wire I&#039;ve had the (dis)pleasure to work with thusfar was 1500kcmil (about 1.5&quot; diameter). High voltage cable is a whole different story. Amps are still amps.</p></blockquote><p></p>

[QUOTE="McIntosh, post: 6151485, member: 605496"] Your basic understanding is quite good, to a point. A wire's capacity is an ampere rating, not a power (watt) rating. Yes you can get ten times the power through the same wire at 120 volts versus 12 volts (Ohm's law P=IE). AC to DC is not apples to oranges by any means, the same laws apply. Given a load (amperes), a wire size and a wire length the voltage drop is the same (for all intents and purposes) whether its 12VDC or 480VAC. There is a difference that matters. Losing 2 volts on a 12V system has a tad more impact than losing 2 volts on a 480V system. Combine that with the fact you need ten times the current to achieve the same power level (120V versus 12V) and the required wire size goes up dramatically. I generally don't work residential, mainly commercial and industrial. Electric ranges, dryers and AC are usually #8 or #6 BTW. Nothing smaller than #14 is allowed in a home (#12 for kitchen, bath and dining room circuits). The largest low voltage wire I've had the (dis)pleasure to work with thusfar was 1500kcmil (about 1.5" diameter). High voltage cable is a whole different story. Amps are still amps. [/QUOTE]

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