Garage Subpanel

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  #1  
Old 12-26-06, 11:32 PM
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Garage Subpanel

I am looking to run electrical service to my new garage. The run from the main panel to the garage is about 100-125 ft. I am looking to install 100A service. I will have to bury the run (at least 18 inches to the top of conduit). I am looking to use copper, Aluminum is allowable in the area but with the high humidity down here (Louisiana) I don't want to have any problems.
I am going to go with a 4 wire run.
What is the proper wire size? I was looking at 1 or 1/0 for the conductors.
What is the proper size PVC conduit for the size/number of wires in the conduit?
With a 4 wire run, is a separate ground rod needed at the garage as well?

Thanks for your assistance.
 
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  #2  
Old 12-27-06, 04:13 AM
william tell's Avatar
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#2 awg , x4 1 1/2 pipe and no grnd rod
 
  #3  
Old 12-27-06, 06:24 AM
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You can use 3 x #4 with a #6 ground in a 1 1/2 conduit.

Yes you need a ground rod at the detached building, and you need to keep the grounds and neutrals seperate in the new sub-panel.

I went here: http://www.csgnetwork.com/voltagedropcalc.html
and did a voltage drop calculation and even maxed out you are way under worrying about VD. If you use this calculator remember that 1/2 half the circuit length is the one way measurement. Circuit length is a two way measurement.
 
  #4  
Old 12-27-06, 07:27 AM
william tell's Avatar
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my mistake white is right bout the grnd rod
or pull 3 wires if no metallic paths to structure
 
  #5  
Old 12-27-06, 08:54 AM
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The ground rod is required either way. If you use a three wire system you do not seperate the grounds and neutrals at the sub panel.
 
  #6  
Old 01-24-07, 11:43 AM
Join Date: Jul 2006
Location: Southeast MI
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For 100A, #4 copper or #2 Aluminum is OK for runs less than 30'. For greater than 30', use #2 Copper or #1/0 Aluminum. Your run is 125', so use the #2 Cu or #1/0 Al.
 
  #7  
Old 01-25-07, 07:11 AM
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Just did the exact same thing...around 125' run, 100A subpanel. Used #2 THWN for the conductors, #6 for the ground. Ran all in 1 1/2 PVC. A ground rod was required at the garage.
 
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