Power to detached garage and greenhouse

Reply

  #1  
Old 01-04-13, 06:53 PM
Member
Thread Starter
Join Date: Jan 2013
Location: USA
Posts: 7
Power to detached garage and greenhouse

I'm working on a plan to run power to a detached garage and greenhouse. The power comes in underground from a transformer to the power meter which is on a short pole about 20' from the home.

Power goes from a panel on the pole to
1) the House service panel,
2) A 240 line to the well
3) A 240 outlet and 120 outlets on the pole.

Here is the plan for the new garage,

1)Install 80 amp breaker at panel on pole
2)Run 4 lines THWN , 3 #4 and 1 #6 copper in conduit to garage(100')
3)Install 125 amp sub panel with grounds isolated from neutrals
4)Install 2 ground rods 6 ft apart

The greenhouse is 40' beyond the garage. I'm not sure how to do this part yet. Can I run another smaller sub panel from the garage sub panel?
 
Sponsored Links
  #2  
Old 01-04-13, 07:45 PM
ray2047's Avatar
Group Moderator
Join Date: Mar 2006
Location: USA
Posts: 33,064
Seeing as you can run a small house on 60 amps what loads do you plan that will require 80 amps?

Can I run another smaller sub panel from the garage sub panel?
Yes.
 
  #3  
Old 01-04-13, 07:48 PM
CasualJoe's Avatar
Member
Join Date: Jan 2010
Location: USA
Posts: 9,400
What is the amperage rating on the main service? How much load is on the main service now? Have you done load calculations on the garage and greenhouse yet? If not, you need to do so. If the loads check out, your plan sounds pretty good. The only thing I would advise is to add a main circuit breaker in the garage subpanel, I don't think you said there would be one in it.
 
  #4  
Old 01-04-13, 08:40 PM
Member
Thread Starter
Join Date: Jan 2013
Location: USA
Posts: 7
Hi Joe and Ray, The main panel is 200 amps and there is a main 125 amp circuit breaker on the sub panel.

The load at the garage won't be that high for now. Lights, compressor, standard outlets for hand held power tools. Might be adding a welder in the future.

I haven't worked out the load on the greenhouse yet. It's a small commercial one(20'x50'). So, it looks like a small sub panel off of the garage sub panel is an option. If the load turns out to be small, could I just run 2 120 circuits from the garage sub panel?
 
  #5  
Old 01-04-13, 09:05 PM
ray2047's Avatar
Group Moderator
Join Date: Mar 2006
Location: USA
Posts: 33,064
If the load turns out to be small, could I just run 2 120 circuits from the garage sub panel?
No. You are only allowed one circuit to a detached structure but you could use 12-3 to run a multi-wire circuit. That would count as only one circuit but could be split at the greenhouse to give you two 20 amp 120 volt circuits.
 
  #6  
Old 01-05-13, 09:40 AM
Member
Thread Starter
Join Date: Jan 2013
Location: USA
Posts: 7
If I go with the multi wire, is the 12-3 big enough? The greenhouse is 40' from the garage. Can this wire go in conduit? and which wire would I purchase?

Jeff
 
  #7  
Old 01-05-13, 10:37 AM
ray2047's Avatar
Group Moderator
Join Date: Mar 2006
Location: USA
Posts: 33,064
Best practice is not to use cable in conduit except short sections as a sleeve to protect it. In continuous conduit installations best practice you would use THWN individual conductors. Less then 100 feet #12 is good.
 
  #8  
Old 01-05-13, 09:01 PM
Member
Thread Starter
Join Date: Jan 2013
Location: USA
Posts: 7
Quadplex breaker

I picked up a Cutler hammer sub panel today. It came with several 20 amp duplex breakers and 1 50 amp quadplex breaker.

I'm curious how the quadplex breaker works. It reads 30 50 50 30, with the 2 50s tied together and the 2 30s tied together.
 
  #9  
Old 01-05-13, 09:13 PM
pcboss's Avatar
Forum Topic Moderator
Join Date: Jul 2002
Location: Maryland
Posts: 14,594
The quad just allows 2 two pole breakers in the space of one double pole breaker. The breakers are paired inside and outside for the two hots.
 
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