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Car Audio Help
Wiring, Electrical & Installation
Power/Current Draw and wire thickness
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<blockquote data-quote="RSDXzec" data-source="post: 7806196" data-attributes="member: 638347"><p>I currently have 8awg power wire to my amp and I was told by a few on here that after 500watts I should upgrade to a higher thickness.</p><p></p><p>What I don't understand is: if P=I^2*R then I=sqrt(P/R)</p><p></p><p>So on a 4 ohm load I could still use this wire for a much higher power draw than on a 1 ohm load. As I understand it, cables are rated for certain currents, not power draw as the current drawn changes at different impedances.</p><p></p><p>My fuse is 60Amps on this wire and my plan is to push 500Watts to a 1.34 ohm load.</p><p></p><p>Using the equation above and using 80% amp efficiency give me 24Amps (my amp is rated at 85% efficiency), even pushing 1000watts I would only be at 34Amps draw.</p><p></p><p>After taking into account box rise the draw would further decrease as the denominator (impedance) would increase.</p><p></p><p>So is there any reason other than the slight increase in Vdrop that would result in needing a thicker wire? Because it certainly can take it.</p><p></p><p>My other question is am I better off buying a second 8awg cable or replacing it with a 4awg wire? which could take more current?</p><p></p><p>Cheers.</p></blockquote><p></p>
[QUOTE="RSDXzec, post: 7806196, member: 638347"] I currently have 8awg power wire to my amp and I was told by a few on here that after 500watts I should upgrade to a higher thickness. What I don't understand is: if P=I^2*R then I=sqrt(P/R) So on a 4 ohm load I could still use this wire for a much higher power draw than on a 1 ohm load. As I understand it, cables are rated for certain currents, not power draw as the current drawn changes at different impedances. My fuse is 60Amps on this wire and my plan is to push 500Watts to a 1.34 ohm load. Using the equation above and using 80% amp efficiency give me 24Amps (my amp is rated at 85% efficiency), even pushing 1000watts I would only be at 34Amps draw. After taking into account box rise the draw would further decrease as the denominator (impedance) would increase. So is there any reason other than the slight increase in Vdrop that would result in needing a thicker wire? Because it certainly can take it. My other question is am I better off buying a second 8awg cable or replacing it with a 4awg wire? which could take more current? Cheers. [/QUOTE]
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Power/Current Draw and wire thickness
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