Technically no. But he was running 3 conductor anyway.
Where did you come up with that? Voltage drop on 18awg on a 15’ run is less than .5v based on 260 kit. Load is significantly less than constant current voltage range on driver too.
I don’t really have any issue with going above and beyond. But #10 definitely isn’t suitable with molex connector, and not very practical with solder pads either. Even 16awg would be in realm of unnecessary.
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As I have said before, I over-engineer pretty much everything… especially my own stuff when it is one-off stuff.
He didn’t specify the distance between the LED board connector and the driver… or what the drive voltage was or series/parallel wiring.
I was simply providing general guidance and that 10AWG stranded should be “good enough” for any reasonable length of extension.
I am not suggesting that the large gauge extension cable be used to connect directly to either the board or the driver/PSU…
You can simply put a short pigtal at the ends with appropriately sized wire to solder to a pad, fit a soldered on terminal connector, or fir the pin size for any Molex connector.
My point was simply to minimize the resistance/voltage drop by using the largest reasonably sized wire/cable stock within budget constraints. 
It depends on what one defines as acceptable voltage drop… I am a lot more picky than most in that regard. 
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No worries, he put it up I figured you missed it.
I wasn’t sure if 2 288’s meant two 135 kits or one 260 kit either. But one is 54v 2.5a output and the other is 119v 2.1a output. I’m pretty sure both are under .5v either way. Its bigger impact on the 54v driver percentage wise, but both are significantly less than 5% maximum I’m pretty sure is standard in national electrical code.
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Thanks!
Yep… NEC 3-5%… depending on where and what’s included…
I’m so OCD, that I generally go for an order of magnitude tighter tolerance… 0.3-0.5%… and this is DC, so I am even pickier, due to my work in designing microcircuits… which can have some pretty finicky voltage tolerances.
Yep… 15 feet, 54VDC, 2.5A, copper:
18 AWG = 0.89% / 0.48VDC drop
10 AWG = 0.14% / 0.075VDC drop
Yes… at 15 feet, even 18 AWG lamp wire will work JUST FINE (assuming that you don’t mind the potential RFI from the parallel conductors) a little higher than I like.
Thanks for being so gracious and tolerant of my compelling NEED to over-engineer.
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I’m familiar enough with code to know that they are “bare minimum requirements”, and will usually go better than tiptoe good enough myself. But like you posted, plenty of room on this one.
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@Carpy @dbrn32 @QST_59 I just measured from the furthest light to where I want to put the drivers 22-25’. 2 will be about that length and 2 will be 2-3’ shorter. So in my situation will 14 gauge be the correct gauge to use?
Thanks guy’s
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The voltage drop on 18awg is about 1.5% there, so it’s still plenty good.
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So yes 14 g is good or use 18 g?
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14 is bigger than 18, so if you want to use it, that would be fine.
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Thanks I have both sizes just want to use what is best.
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@RAP - The bigger the wire, the smaller the voltage drop… It’s all about how small you want it to be… Look up above in my earlier response and find the calculator/table length I posted.
As AWG gets smaller, wire size gets bigger… You can use 18, 16, 14, 12, 10… Short answer… YES, you can use either. 14 AWG will probably cut the drop in half or by 2/3rds…
IF I had both… I’d use 14 AWG.
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@dbrn32 @QST_59 I dug out my wire today. I have stranded 14 gauge. 500’ roll some gone. So I will need to run 2 wires from the driver to the boards. How important is running a ground wire? I have enough probably to run a third wire to and from each driver/board if needed.
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Assuming that all of your LED boards are mounted to heatsinks, and all of those heatsinks are metal to metal to the hopefully metal frame… you only need ONE ground wire from the drive to some place electrically common to ALL LED boards… the metal frame of the fixture.
As we discussed earlier, the ground wire is not technically required, but I have rethought my position on this… No reason not to do it. And considering that the light is in a room where water with a high EC is regularly handled… not a bad extra safety measure.
So three wires… + and - between the LED boards and Driver DC supply, plus a third wire bonded to the Driver case, and the light fixture frame or a heatsink (IF multiple heatsinks are connected electrically by the frame.
Twist all three wires as instructed above to get RFI protection and to make the wire more cable-like in management.
Alternatively, you could use a section of AC extension cord wire if you have one you can hack up…
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If you don’t run a ground, you won’t have a ground. The driver will protect on a short or ground fault, but as soon as fault is removed driver will try to fire leds.
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3 wires each it is.
Thanks
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Ahhh… I’m a moron… I thought you had made ONE light from 4 boards and a big driver… You have two complete lights with 2 drivers.
Yes… one ground per kit… Sorry. I should read more closely. 
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No this is for my 4 QB 260 XL’s in the tent . Just cut 25’ lengths and ended up one short. I will get it tomorrow. The wire is yellow so I will use perm marker to color 2 each before I twist tomorrow.
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Never mind… I’m not hitting on all cylinders today…
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