What size sub-panel/wire-size/breaker size?

Reply

  #1  
Old 12-08-04, 10:22 AM
Member
Thread Starter
Join Date: Dec 2004
Location: Minneapolis
Posts: 28
Question What size sub-panel/wire-size/breaker size?

I need to put a sub-panel in my attached garage. My hobby is woodworking so I have a table-saw, dust collector (both I want to convert to 220)..lighting, heating (going to be installing one of those gas radiant tube heaters) and tv....

The distance from my main panel (200amp) to the sub-panel location is about 60ft. I will be running the feeder wire through the trusses of the first floor (scissor trusses not I beam).

Here are my questions:
If I have a 100 amp sub-panel can I feed that with 6ga copper wire? I understand that the biggest breaker I can have on that wire is 60amp? Or do I need a 60 amp panel? Does the feeder wire have to be in conduit?

thanks
Doug
 
Sponsored Links
  #2  
Old 12-08-04, 11:28 AM
Member
Join Date: Sep 2000
Location: United States
Posts: 18,497
The size of the feeder wire must be large enough for the feeder breaker. The rating of the subpanel must be at this level or higher. So yes, you can certainly have a panel rated for 100-amps on a 60-amp feeder. But this makes it a 60-amp subpanel, not a 100-amp subpanel.

The feeder must be physically protected. There are lots of ways to do that. Conduit is one. Are you running 6/3 NM-B, or THHN?
 
  #3  
Old 12-08-04, 02:31 PM
Member
Thread Starter
Join Date: Dec 2004
Location: Minneapolis
Posts: 28
I was planning on using 6/3 NM-B. Thanks for clarifying on the sub-panel size/feeder size. I have a 100 amp sub that I bought on sale and I was hoping that I could still use it.
 
  #4  
Old 12-08-04, 02:43 PM
Member
Join Date: Jan 2002
Location: Chicago
Posts: 1,915
The size of the panel is the maximum it can handle safely. You can't feed it with more then 100A.
 
  #5  
Old 12-08-04, 03:04 PM
Member
Join Date: Sep 2000
Location: United States
Posts: 18,497
It is not adviseable to run the 6/3 NM-B inside conduit except for short distances where it might be subject to substantial risk of physical damage. I realize that this is vague, but every situation is different.
 
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
'