Wire Size Question - Electrical - DIY Chatroom Home Improvement Forum


Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Electrical

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Display Modes
Old 05-11-2012, 09:07 PM   #1
Newbie
 
Join Date: May 2012
Posts: 7
Rewards Points: 10
Default

Wire Size Question


I have a barn that I need to run a feeder wire to from a 200 amp meter base 100 feet from the panel in the barn, the barn has a 125 amp main lug 4 circuit 4 space panel in it now.

the 200 amp meter base has no other use but the barn. I have approx 20 lights, a small fridge, air comressor and a well pump that is approx 500 feet from the barn and 300 ft deep

what size wire do I need to run from the meter base to the panel in the barn

thanks much

Advertisement

Ridgerunnertc is offline   Reply With Quote
Old 05-11-2012, 09:13 PM   #2
Member
 
Missouri Bound's Avatar
 
Join Date: Apr 2011
Location: Almost Arkansas
Posts: 2,764
Rewards Points: 2,000
Default

Wire Size Question


See if this helps.Wire Size Calculator...............

Advertisement

__________________
Do you want it your way or the right way?
Missouri Bound is offline   Reply With Quote
Old 05-11-2012, 11:02 PM   #3
Master Electrician
 
Join Date: Mar 2010
Location: Toronto Ontario
Posts: 1,165
Rewards Points: 500
Default

Wire Size Question


would need to know what the amperage is for the well pump. Basically from what little i know of the NEC i believe that feeders are rated to 3% votage drop and branch circuits are rated to 3% voltage drop. The two combined can't exceed 5% to the furthest branch circuit. Having said that if the voltage drop is a go then you'll need a #3 copper for a 100A main breaker and #2 if it's a 125A main breaker.
__________________
Sarcasm is my friend
I'm here to learn too, i do mostly commercial/industrial/new construction and this place is a great way to pick up tips on residential from some good electrical minds. Excuse the spelling, my phone has a mind of it's own.
andrew79 is offline   Reply With Quote
Old 05-12-2012, 07:51 AM   #4
Member
 
Code05's Avatar
 
Join Date: May 2009
Location: Easton MD
Posts: 1,841
Rewards Points: 1,000
Default

Wire Size Question


Quote:
Originally Posted by andrew79 View Post
would need to know what the amperage is for the well pump. Basically from what little i know of the NEC i believe that feeders are rated to 3% votage drop and branch circuits are rated to 3% voltage drop. The two combined can't exceed 5% to the furthest branch circuit. Having said that if the voltage drop is a go then you'll need a #3 copper for a 100A main breaker and #2 if it's a 125A main breaker.
While a good idea in many cases, except for fire pumps and sensitive electronic equipment wired off a 60/120 transformer, the NEC does not require you to adjust/compensate for voltage drop.

It is only recommended.
Code05 is offline   Reply With Quote
Old 05-12-2012, 08:04 PM   #5
Master Electrician
 
Join Date: Mar 2010
Location: Toronto Ontario
Posts: 1,165
Rewards Points: 500
Default

Wire Size Question


Section 215-2(b) FPN No. 2. Conductors for feeders as defined in Article 100, sized to prevent a voltage drop exceeding 3 percent at the farthest outlet of power, heating, and lighting loads, or combinations of such loads, and where the maximum total voltage drop on both feeders and branch circuits to the farthest outlet does not exceed 5 percent, will provide reasonable efficiency of operation.

i found that and assumed it was a rule, we have to size for voltage drop up here so i assumed it would be the same. Seems silly not to follow it. At 800 feet to the pump who knows if it will even turn on.
__________________
Sarcasm is my friend
I'm here to learn too, i do mostly commercial/industrial/new construction and this place is a great way to pick up tips on residential from some good electrical minds. Excuse the spelling, my phone has a mind of it's own.
andrew79 is offline   Reply With Quote
Old 05-12-2012, 08:13 PM   #6
Electrical Contractor
 
jbfan's Avatar
 
Join Date: Jun 2004
Location: Newnan GA
Posts: 5,955
Rewards Points: 2,306
Default

Wire Size Question


Fine print notes are not a requirement, but a suggistion.

That's not to say you should'nt adjust, just not required.
__________________
Yes I am a Pirate, 200 years too late. "Jimmy Buffett"
jbfan is online now   Reply With Quote
The Following 2 Users Say Thank You to jbfan For This Useful Post:
andrew79 (05-13-2012), Code05 (05-12-2012)
Old 05-13-2012, 06:54 PM   #7
Newbie
 
Join Date: May 2012
Posts: 7
Rewards Points: 10
Default

Wire Size Question


the well pump tag says 9 amps, the pump is 550 feet away from the barn and is a 300 ft submersible well pump, I have 8-2 wire run for the 550 feet to the well pump pressure switch and then 12-2 wire down the well to the pump

Advertisement


Last edited by Ridgerunnertc; 05-13-2012 at 06:55 PM. Reason: spelling
Ridgerunnertc is offline   Reply With Quote
Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
wire size question analogmusicman Electrical 8 09-01-2011 07:17 PM
What size ground wire should I use for 8 gauge power dxmullin Electrical 1 07-06-2011 03:57 PM
Question about neutral wire through wall switch guitarmonster Electrical 33 08-08-2010 10:51 PM
hooking up dryer....bronx ny code SURFBUG Appliances 6 10-14-2008 10:41 PM
Aluminum wire size/ guage / amps? walt1122 Electrical 17 07-30-2008 11:44 AM




Top of Page | View New Posts