Another power distro thread

B

BJ James

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Jan 11, 2011
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I have a Versarray system. 6 hang a side and a total of 4 double 18's subs. When I've been using it for smaller shows I usually just do a 3 hang a side over 1 sub. My amp rack to run this system consists of a PL325 for hi's, PL340 for mids and a PL380 for subs. I have the DSP mounted in the rack along with the I/O panel and an ampshop PD that uses a california 50a inlet. The odd time that I use the full system I simply wire up the extra 3 amps and plug them into the same PD. Have not had any issues even though the total draw COULD exceed the 50a.
What I'm trying to figure out is the best way to have two nearly identical racks, keeping most of what I already have in use. So the second rack would have the same amps and DSP. I hate the thought of running 50 or 75' of 6/4 across the stage to connect the second rack. My thought is to get a PD that has the 50a inlet but has a 20a (240v) passthrough to the second rack. Then I could get away with using cheaper and more managable 10/4 to the second rack.
At this point I'm not using any other distro, so backline and active monitors also get power from the 50a PD in use.
Looking for suggestions on how to proceed.
BJ
 
Re: Another power distro thread

10/4 will run 50 amps no problem. (25 per leg) Run that to your cross stage rack like you said. Have you ever measured what your full rig actually draws? I was shocked recently to discover that mine draws about 13 amps per leg outdoors in a typical small fest setting. I run 4 18" 1000 watt subs, 2 dual 12 mids, 2 - 2", 2-1", 8 wedges, drum fill and backline off my 50A 220 dist. Thank you ISP Technologies.
 
Re: Another power distro thread

TJ Cornish said:
Your information is correct but your teminology is dangerous - 10/4 will indeed handle 25 amps per leg at moderate distances, but it's NOT a 50 amp circuit - it's a 25 amp circuit with a center tap.
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It's only center tapped if it's single phase. With three phase it is simply a 208 volt circuit, with 120 volts available each leg to neutral.
 
Re: Another power distro thread

Thanks for the clarification. So 10/4 is perfectly fine for 30A 240v then? I think I may have a chunk of that still kicking around....I thought I would have to go larger.
 
Re: Another power distro thread

BJ James said:
Thanks for the clarification. So 10/4 is perfectly fine for 30A 240v then? I think I may have a chunk of that still kicking around....I thought I would have to go larger.
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Yes. The L14-30 connector is sort-of an unofficial industry standard for this type of thing. You would have plenty of head room running your amp rack on 10/4 with an L14-30.

If it were me, I would convert both racks to L14-30 and put the 50 amp distro in it's own case with 2-3 L14-30's and some convenience outlets. This lets you swap out amp racks in case one needs service. Not to mention you could crossrent gear from a bigger soundco and still be compatible.
 
Re: Another power distro thread

Tim Weaver said:
Yes. The L14-30 connector is sort-of an unofficial industry standard for this type of thing. You would have plenty of head room running your amp rack on 10/4 with an L14-30.
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Except that 10/4 flexible cable is not rated for 30A (unless you don't consider the neutral conductor to be current-carrying, which you can only do if you have linear loads).
 
Re: Another power distro thread

Shane Presley said:
I think you would be ok with 8/4 my friend (at least that's what I understand from motion labs)
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'I think' is not what you want to hear when talking about power.

Refer to NEC 400:
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