I've got four 60 amp 5 volt power supplies, and I'm sending power to a sculpture with 3000 RGB leds. So here's the total power picture we're looking at...
3000 * 5 volts * 3 leds per pixel * .02 amps = 900 watts. At 5v that's 180 amps.
My power supplies are rated for 240 amps, so I'm comfortably within my margins there. Also, my piece will only have around 50% of the lights on at any time, also the lights won't be white, so they will be using less than .02*3 leds of power...
So. What's our safety margin here... something like 500 watts seems like a good normal load, with occasional spikes higher.
(if any of this seems bogus, feel free to point that out)
My main question is this... What size cabling should I use to send power up to the art piece from the power supply box? I was looking at NEC standards and it was saying something like 4 gauge... but it was only asking me about amps used... And I think that's for 120 volts. Does it matter that I'm only sending power at 5 volts?
The cables from the power supply box to the sculpture will be around 20 feet long.
(Oh - and if you want to check out the art piece in progress, I'm posting a lot of it here... https://www.facebook.com/skylightpdx/ )