Whar Size Ground Wire Do I Need?

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Old 05-02-16, 06:58 PM
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Whar Size Ground Wire Do I Need?

I an trying to install two 100 watt pole lights at the end of my driveway and a receptacle in a weatherproof box to run a occasional leaf blower or drill. The run from the panel is 465 feet. I have calculated I need #6 wire to make the run with a 5% voltage drop. Question is, do I also need to run a #6 ground as well, or can the ground wire be a small size such as a #8 or #10?
 
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Old 05-02-16, 07:05 PM
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Wow... that's quite a run.

If you ran the circuit as 240v you would have lower drop on smaller wire but would be forced to use a transformer to convert to 120v.

Are you going to be running the circuit in conduit ?
What size breaker will be feeding the circuit ?
The ground wire can be smaller than the hot and neutral. I believe a #12 green would be adequate.
 
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Old 05-02-16, 07:05 PM
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With the #6s, I'd run a #10 ground.
 
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Old 05-02-16, 07:06 PM
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The ground wire could certainly be a #8 or a #10 but the question comes down to what kind of cable (wire) are you going to run for the circuit? If you are going to use conduit and pull individual conductors it's very easy to have a different size ground but if you're using direct burial cable you are pretty much at the mercy of the manufacturers as to what combinations they have available.
 

Last edited by Msradell; 05-02-16 at 07:27 PM.
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Old 05-02-16, 07:11 PM
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I based my reply on breaker size. The ground wire would not need to be larger than the supply breaker.
 
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Old 05-02-16, 08:18 PM
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Running #6 conductors you have to run a minimum of a #10 ground.
 
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Old 05-02-16, 08:26 PM
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The ground would need to be up sized by the same percentage as the hots over the normal size.
 
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Old 05-04-16, 05:04 AM
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Yes, I will be pulling THHN through 1" PVC conduit.
 
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Old 05-04-16, 09:45 AM
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I will be pulling THHN
You will need THWN not THHN. Most wire is dual rated THHN/THWN just check the labeling on the wire to be sure.
 
 

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