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How long is to long?? whats the max length I should run 12/2???

How long is to long?? whats the max length I should run 12/2???

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  #1  
Old 07-25-13, 02:53 PM
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How long is to long?? whats the max length I should run 12/2???

Hello,
I am building a house. I would like to run a 12/2 wire beside the drive way (550ft) for a light and a gate alarm.
My question is will the voltage drop be to much for this distance? Is this to far to try this?

All input welcome
Thanks
 
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  #2  
Old 07-25-13, 03:10 PM
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Welcome to the forums!

First of all 12/2 what? Type UF?

The voltage drop over 550' will be pretty significant. How much power, in amps, do you need at the end?
 
  #3  
Old 07-25-13, 03:24 PM
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yes its the 12/2 uf, on a 120 circuit. Not looking to run much off of it, few lights and a gate alarm. Might run a small pond pump motor about half way down the line every now and again.
 
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Old 07-25-13, 03:34 PM
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What about the gate itself? Is it electric? To do it once, I would run 10-3 wg UF. Even if you only use one of the hots, save the red to install as a multi wire branch circuit later on in the event you decide to install something else with a larger draw. Go ahead and install a double 20 amp breaker and only wire the black to it, capping off the red on both ends. What's your idea on that, Bill???
 
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Old 07-25-13, 03:43 PM
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I want to hear the amp load, Larry. 550' is a very long run. For one quick example, supplying a 5 amp load at that distance with a voltage drop of no more than 3% requires #6 AWG copper conductors.

I like the MWBC idea. I would use the second circuit right away, for that pump. In fact, I would stop the 3-conductor there and continue to the gate with 2-conductor on the other circuit.
 
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Old 07-25-13, 03:51 PM
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Gate is manual. Would it be a good idea to send the 120 down the line and convert it to 12vdc and run 12v lights and alarm?
 
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Old 07-25-13, 03:54 PM
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Amps I am not sure of. I guess a 60 watt bulb or two, Gate alarm should be well under 5 amps.
 
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Old 07-25-13, 04:08 PM
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Two 60W bulbs draw 1 amp total @ 120V. That leaves you with 4 amps for the gate alarm with the 6 AWG conductors.

Pick an alarm you like and read the spec sheet - it will tell you the load.

BTW, enough 6-3/G UF-B to maybe get you to the pond - a 250" roll - is priced at $611.15 from one supplier I checked.
 
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Old 07-25-13, 04:10 PM
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Gate is manual. Would it be a good idea to send the 120 down the line and convert it to 12vdc and run 12v lights and alarm?
Probably not, because then you've got the inefficiency of the converter to feed in addition to the loads you'll be using. It might be better to send 12V DC from the house and get a DC pump and light bulbs.
 
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Old 07-25-13, 04:23 PM
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OK,, I guess I might have to scratch the pond pump for now, I have already bought the 12/2 wire. I was really hoping to get by with it, but not looking like a good idea. the 12/2 cost me almost 300. And that was way more then I wanted to spend. Maybe I could get some old wire from the Power co
 
  #11  
Old 07-25-13, 05:07 PM
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You might be able to use it if everything is DC. Copper isn't cheap anymore.
 
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Old 07-25-13, 05:29 PM
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If you can find a cheap 240::120 step down transformer on Ebay you could run 240. That would help with the voltage drop. Or sell the cable you bought and buy #4 aluminum URD.
 
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Old 07-25-13, 05:56 PM
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Boy, did I read the length wrong I was thinking 150, not 550!!!
Yeah for minimal voltage drop (4.7%) you would need a 6-3 for that run. Sorry about the mistake. Have you thought about solar with batteries in a small doghouse type shed?? You could use the low voltage with that.
 
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Old 07-25-13, 06:35 PM
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Have you thought about solar with batteries in a small doghouse type shed??
That sounds like a very workable solution, and way cool too.
 
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Old 07-25-13, 07:40 PM
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To do it once, I wouldn't use UF cable; I'd use PVC conduit and THHN/THWN conductors.
 
  #16  
Old 07-29-13, 09:12 PM
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You already bought the wire, I'd say its worth a try!
Besides, the impedance of 12AWG copper over 1000ft is less than 2 ohms, you're talking like 5 VAC lost over the entire run with a 5 AMP draw.. If your alarm has a switching power supply I'm sure it's rated down to 90 VAC, so plenty of margin.

I would roll out the wire the length of the drive above ground, plug in 5-10 amp load at the end and see how well it works. If you have a volt-meter you can measure the drop at the end (measure it under a decent load to get a realistic reading)

http://www.hmwire.com/pdf%20files/Oh...3.10.20.08.pdf
 
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