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<blockquote data-quote="TJ Cornish" data-source="post: 137599" data-attributes="member: 162"><p>Re: Sound & Stage Power</p><p></p><p></p><p></p><p>Wire size depends on the size of the upstream over-current protection device. If you have a 50A breaker, you need to use wiring rated for at least 50A in the circumstance you're using it. For SOOW cord, that's #4. Some electrical inspectors will let #6 slide, but it does not pass the letter of the law, and is foolish anyway - the extra voltage drop at lengths we use is like buying a Lamborghini but refusing to put anything other than 87 octane fuel in it.</p><p></p><p>There are various voltage drop calculators around the net where you can play with numbers. The general rule of thumb is you only want a 3-5% voltage drop from the branch circuit wiring. Many calculators must have the round-trip length entered - i.e. a 50' cord is actually 100' of copper for the circuit. Also, as you mentioned, audio load is non-linear. The good news is that the average power is low; the bad news is that the instantaneous draw can be VERY high - several times the rating of the breaker, which means that the true voltage drop is much higher at the point of peak draw than what the calculator shows for a fully-loaded breaker.</p><p></p><p>I have started writing a series of articles on power consumption and distribution. Take a look: <a href="https://soundforums.net/content/2631-Understanding-Power-Consumption-Part" target="_blank">Understanding Power Consumption</a></p><p></p><p>What's your rig? How do you know you need 100A (presumably 120V) per side?</p></blockquote><p></p>
[QUOTE="TJ Cornish, post: 137599, member: 162"] Re: Sound & Stage Power Wire size depends on the size of the upstream over-current protection device. If you have a 50A breaker, you need to use wiring rated for at least 50A in the circumstance you're using it. For SOOW cord, that's #4. Some electrical inspectors will let #6 slide, but it does not pass the letter of the law, and is foolish anyway - the extra voltage drop at lengths we use is like buying a Lamborghini but refusing to put anything other than 87 octane fuel in it. There are various voltage drop calculators around the net where you can play with numbers. The general rule of thumb is you only want a 3-5% voltage drop from the branch circuit wiring. Many calculators must have the round-trip length entered - i.e. a 50' cord is actually 100' of copper for the circuit. Also, as you mentioned, audio load is non-linear. The good news is that the average power is low; the bad news is that the instantaneous draw can be VERY high - several times the rating of the breaker, which means that the true voltage drop is much higher at the point of peak draw than what the calculator shows for a fully-loaded breaker. I have started writing a series of articles on power consumption and distribution. Take a look: [URL="https://soundforums.net/content/2631-Understanding-Power-Consumption-Part"]Understanding Power Consumption[/URL] What's your rig? How do you know you need 100A (presumably 120V) per side? [/QUOTE]
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