What size wire for 250ft run?

Reply

  #1  
Old 07-16-07, 09:20 AM
crabjoe's Avatar
Member
Thread Starter
Join Date: Apr 2004
Location: USA
Posts: 287
Received 0 Votes on 0 Posts
What size wire for 250ft run?

I need to run electric to my shed which is almost 250ft from the main panel. I need a minimum of 20amps (120) there so I can run a table saw, but ideally, I'd like to get install a 50amp sub panel. So what size wire do I need?

A friend of mine says if I want 20 amps, all I need is 8awg copper, but the online calculators keep telling me either 3 awg for aluminum or 4 awg for copper.

What is correct?

Thanks!!
 
Sponsored Links
  #2  
Old 07-16-07, 09:27 AM
Member
Join Date: Sep 2003
Location: Central New York State
Posts: 13,973
Received 0 Votes on 0 Posts
You are correct, if you really want 20 amps available on a 120 volt circuit and wish to keep voltage drop to less than 3 percent.

However, you can do much better than that.

Look for aluminum mobile home feeder cable, and use that to run a sub panel.
 
  #3  
Old 07-16-07, 09:47 AM
Forum Topic Moderator
Join Date: Feb 2005
Location: Near Lansing, Michigan
Posts: 10,944
Received 42 Votes on 40 Posts
Agreed. Use a #2-2-2-4 aluminum mobile home feeder direct-burial cable with a 50A subpanel. It's sold as a 100A cable, but should only be used for 50A at your distance. The #2 aluminum cable probably isn't too much more expensive than the #8 copper.
 
  #4  
Old 07-16-07, 08:50 PM
crabjoe's Avatar
Member
Thread Starter
Join Date: Apr 2004
Location: USA
Posts: 287
Received 0 Votes on 0 Posts
Thanks folks... I guess I'll need to find a low cost source for some 2224. It's going to cost me way more then I want to spend, but it's way cheaper then copper.
 
  #5  
Old 07-23-07, 10:31 AM
Member
Join Date: Apr 2006
Posts: 46
Received 0 Votes on 0 Posts
Costs.....

Just a word from another DIY'er....... I just ran 220 80'.With 3 #4's and 1#8 as ground...... All copper ..... It cost (just for the wire) $640.00 ......... Ouch
 
  #6  
Old 07-23-07, 08:48 PM
Member
Join Date: Nov 2004
Location: USA
Posts: 973
Received 0 Votes on 0 Posts
Suggestion: Check and see if your table saw motor can be wired to run at 220V. My understanding is that the voltage drop for 220V is 1/4 that of 110V.
 
  #7  
Old 07-24-07, 12:10 AM
Member
Join Date: Aug 2004
Location: NA
Posts: 1,065
Received 1 Vote on 1 Post
The voltage drop for 240 volts is the same as 120 volts.

Roger
 
  #8  
Old 07-24-07, 10:36 AM
Forum Topic Moderator
Join Date: Sep 2005
Location: USA
Posts: 4,719
Received 29 Votes on 28 Posts
The voltage drop is the same, but is less of an impact. For example, a table saw at 120v may pull 16A, but at 240v will only pull 8A. 16A over a long distance will have more of a voltage drop than 8A.

So my understanding is that all else being equal, wire larger equipment at 220 vs 120 (presuming it's designed as such).
 
Reply

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


Thread Tools
Search this Thread
Display Modes
 
Ask a Question
Question Title:
Description:
Your question will be posted in: