sub panel in barn

Reply

  #1  
Old 11-14-05, 08:46 AM
Member
Thread Starter
Join Date: Dec 2004
Location: Taylorsville, MD
Posts: 27
sub panel in barn

I'm in the planning stage of running electric to a barn behind my house. The distance from panel to panel will be about ~180 feet. I'm using direct burial "mobile home feeder" in a 2/2/2/4 configuration buried ~36" below grade with a low voltage conduit above that (same trench) at ~24" down. I will have a 100 amp breaker in the main panel and 100 amp breaker in the subpanel. The barn will only have lighting and outlets (total right now 14), nothing major on two 15 or 20 amp circuits.

my questions are:

1. does everything mentioned look ok?

2. ground rod at barn?

3. ground between panels?

4. anything i've missed or overlooked?

thanks!

-mark-
 
Sponsored Links
  #2  
Old 11-14-05, 09:02 AM
Forum Topic Moderator
Join Date: Feb 2005
Location: Near Lansing, Michigan
Posts: 10,337
Originally Posted by mathey
1. does everything mentioned look ok?

2. ground rod at barn?

3. ground between panels?

4. anything i've missed or overlooked?
1. Yes
2. Yes, it is mandated by code.
3. Yes, it is mandated because you have an alternate "metallic pathway" between the structures through the low voltage cables. It would be highly recommended anyway.
4. The grounds and neutrals must be isolated in the subpanel. Usually this means removing the bonding screw or strap from the subpanel and purchasing an add-on ground bar kit. Also, the feeder wires must be protected by conduit where it enters and exits the ground vertically with a 90 degree sweep horizontal at the bottom of the trench.

EDIT: Your general purpose receptacles in the barn should be GFCI protected if they are not in a drywalled/finished room.
 
  #3  
Old 11-14-05, 10:42 AM
Member
Join Date: May 2001
Location: Dry Side of Washington State
Posts: 738
You keeping livestock/poultry in that barn?
 
  #4  
Old 11-14-05, 11:00 AM
Member
Thread Starter
Join Date: Dec 2004
Location: Taylorsville, MD
Posts: 27
there is a stall for a horse that is in there occasionally, and some barn cats
 
  #5  
Old 11-14-05, 11:54 AM
Member
Join Date: Jan 2004
Location: Oregon
Posts: 1,219
Copper or aluminium conductors? If aluminium, I would _recommend_ that you place the cable in conduit. This is not a requirement; it is, after all, direct burial cable.

Also, for this application, you must select ampacity from NEC table 310.16; if your cable is aluminium then a 100A breaker is too big. (Although different inspectors in different locations have a different take on this; some will permit you to use table 310.15(b)(6), which would make your cable okay for 100A.)

-Jon
 
  #6  
Old 11-14-05, 12:10 PM
Member
Thread Starter
Join Date: Dec 2004
Location: Taylorsville, MD
Posts: 27
i believe the cable is aluminum...honestly, i will most likely use a 60 amp breaker in both panels, which is still way more than i will ever need.
 
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
'