100 AMP subpanel to pole barn HELP!!!

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  #1  
Old 12-17-05, 08:11 PM
carguynj
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100 AMP subpanel to pole barn HELP!!!

Let me start out by saying that this is a great website filled with alot of knowledgeable people. ........Now I built a Garage (pole barn) behind my house and have begun to tackle the electric my self and need to ask some questions. Here is what i have...

150 Amp Service in my House
2/0 alum. 4 wires h/h/n/g run from panel to panel underground (not tied in yet) in 2 1/4 in grey pvc
voltage drop around 3%
100amp simmens panel for garage
distance is 240 feet panel to panel not pole to panel

Where do I go from here? How do tie in the wires in my existing box? It seems that there is no room for the 2/0 n or g wires. They appear too big to anchor. The hots fit fine in the 100a breaker.

Do I use a Ground Rod or Not.? (no plumbing in garage)

Could I have used plain white PVC? I was told no. Too late now just wanted to know.


Thanks in advance for all of your input.
 
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  #2  
Old 12-18-05, 05:49 AM
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Join Date: Oct 2005
Location: Milwaukee WI
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Originally Posted by carguynj
Where do I go from here? How do tie in the wires in my existing box? It seems that there is no room for the 2/0 n or g wires. They appear too big to anchor.
Check with the mfgr. of the existing load center in your house. They may have a rated adapter to give you additional space for large conductors. If not, maybe somebody else has an idea.

Also make sure you use no-ox and a wire brush on all aluminum terminations to reduce oxidation and heating.

Originally Posted by carguynj
Do I use a Ground Rod or Not.?
Sorry, I don't know.

Originally Posted by carguynj
Could I have used plain white PVC? I was told no.
White plumbing PVC would not have met code requirements.
 
  #3  
Old 12-18-05, 12:04 PM
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Join Date: Feb 2005
Location: Near Lansing, Michigan
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Originally Posted by carguynj
It seems that there is no room for the 2/0 n or g wires. They appear too big to anchor. The hots fit fine in the 100a breaker.
You need to buy a neutral lug kit for your panel. Take the model and make to an electrical supply house, and they will know exactly what you need. If you have a modern, brand name panel Home Depot or similar store will sell one to fit your panel. It looks like a hollow metal playing die with a small screw to mate with the neutral bar and a large screw to clamp down the 2/0 conductor.

Use an aluminum wire de-oxidizer on the aluminum wire terminations at both ends. Torque the lugs to spec, and after a couple weeks of use kill the power to the barn and re-torque the aluminum wire lugs.

Do I use a Ground Rod or Not.?
Yes. An 8' long 5/8" diameter copper ground rod is mandatory for a detached structure.

Remember that your grounds and neutrals must remain seperated in the barn subpanel; most of the time that means you need to purchase an ground bar add-on kit for the subpanel and remove the bonding screw/strap.

Could I have used plain white PVC? I was told no. Too late now just wanted to know.
No, you cannot use DWV white PVC for electrical conduit. It is not UL listed as conduit, the radius of the elbows to too tight, and it doesn't have the temperature ratings that electrical conduit has.
 
  #4  
Old 12-19-05, 05:42 AM
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Location: Taylorsville, MD
Posts: 27
just curious as to how you came up with a 3% voltage drop...

the calculator I used, for a 100amp load at 240 ft, 120-2 phase using 2awg aluminum shows the drop to be 6.4%...
 
  #5  
Old 12-19-05, 05:56 AM
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Location: Central New York State
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Originally Posted by mathey
just curious as to how you came up with a 3% voltage drop...

the calculator I used, for a 100amp load at 240 ft, 120-2 phase using 2awg aluminum shows the drop to be 6.4%...
He's not using 2 awg, he's using 2/0 aluminum. (And it's not 2 phase. It's single phase, 240 volts.)
 
  #6  
Old 12-19-05, 06:56 AM
carguynj
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Thanks for all of your input. Im sure I will be picking your brains for more info soon. Thanks
 
  #7  
Old 12-19-05, 11:34 AM
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Join Date: Dec 2004
Location: Taylorsville, MD
Posts: 27
I mis-read...my bad
 
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