Detached Shed/Well house; Can I use a 30a disconnect?

Reply

  #1  
Old 03-30-13, 04:57 PM
Member
Thread Starter
Join Date: Mar 2013
Location: USA
Posts: 12
Received 0 Votes on 0 Posts
Detached Shed/Well house; Can I use a 30a disconnect?

I built a shed to mainly serve as a well house. The electric run from house to shed is 165 ft. From shed to well head is 45 ft. and the depth of well is about 95 feet. It will house a pressure tank and the like, as well as the irrigation system. Those are the only things that will be used 99% of the time. I am planning to install 2 light switches which will provide power to two lights a piece. I am also going to install 4 receptacles in case a need ever arises in which I might need to plug something in. This will be extremely rare as it will only be housing lawn mowers and such. Now, to my questions.

1. I am wanting to do this as simply as possible. That being said, can I just install a 30 amp disconnect to do all the above? The well pump is Ĺ hp. It wonít pull more than 6 or so amps at peak. This is the only thing that might be running 99% of the time. If so, what wire will I need to pull from house to shed? 10/3?

2. If a disconnect wonít work, what do you all suggest? I hate to think Iím going to have to install a 100 amp sub-panel and then run 3 runs of THWN #4 or possibly #2 as well as a #8 for ground. Thatís a lot of work and expense that Iím hoping to avoid.

I have a few more questions, but Iíll ask once I get input on what scenario above is best for this project.

TIA!
chi_town

Name:  shed.png
Views: 1924
Size:  11.7 KB
Name:  wiring.png
Views: 5012
Size:  14.8 KB
 
Sponsored Links
  #2  
Old 03-30-13, 05:10 PM
Group Moderator
Join Date: Oct 2004
Location: WI/MN
Posts: 19,393
Received 59 Votes on 55 Posts
Welcome to the forums.

The pros will be along shortly to answer with certainty but I don't think you can run everything you're proposing here off the single feed allowed to a detached building. Yep, sub panel is what I think you're going to need.
 
  #3  
Old 03-30-13, 05:16 PM
ray2047's Avatar
Member
Join Date: Mar 2006
Location: USA
Posts: 33,597
Received 13 Votes on 11 Posts
can I just install a 30 amp disconnect to do all the above?
No, a general purpose 120 volt lighting circuit can not be greater then 20 amps but a 60 amp, six space subpanel will work fine. No disconnect need as long as the subpanel has six spaces or less.

Because of the distance you will need 8-3 minimum. That can be either 8-3 UF or three #8 THWN and one #10 THWN in conduit (assumes copper). You would need at least one ground rod at the subpanel. Since the subpanel probably won't come with a ground bar you will need to install one. The ground bar will be bonded and neutral isolated. You can use a 30 amp two pole breaker at the house.
 
  #4  
Old 03-30-13, 07:56 PM
Tolyn Ironhand's Avatar
Group Moderator
Join Date: Nov 2007
Location: Twin Cities, MN
Posts: 13,022
Received 68 Votes on 60 Posts
Welcome to the forums!

I do agree with Ray about installing a small sub panel, feeding it with a 30 amp breaker in the main panel, and the grounding requirements.

However, IMO you only need to run 10/3 UF-b to the shed (or 4 #10 THWNs in conduit) Ray is thinking the voltage drop would be too great at 165', but voltage drop is effected by load as well. Figuring your load won't be more than 20 amps at any one time, your voltage drop would still only be a little over 3%.

The sub panel would give you the most flexibility in the future and only add about $40 to the cost of the project.

Just remember that UF needs to be buried 24" down, and PVC conduit 18" down.
 
  #5  
Old 03-31-13, 01:44 PM
Member
Thread Starter
Join Date: Mar 2013
Location: USA
Posts: 12
Received 0 Votes on 0 Posts
Thanks for the info gentlemen. Do you guys have a place to pick up a 60 amp, 6 space load center? I can only find a 2 space, 4 circuit breaker and only online at that. Would a 70amp work and just use a 60amp breaker in the main? I only ask because I can get a 70 amp at the big box store.

About the wire; am I correct in believing I need black, green, red and white? Also, I've always been a bit confused about this; do I need a 5th wire, bare, as a ground?

Again, I appreciate all of the info. I'm sure I'll have more questions and you all are quick with great responses!

chi_town
 
  #6  
Old 03-31-13, 03:20 PM
ray2047's Avatar
Member
Join Date: Mar 2006
Location: USA
Posts: 33,597
Received 13 Votes on 11 Posts
Would a 70amp work and just use a 60amp breaker in the main? I only ask because I can get a 70 amp at the big box store.
You would still use a 30 amp breaker and #10. The only difference is if it has more then six spaces you will need a disconnect. You cheapest route may be a 100 amp main breaker panel kit if the seventy amp has more then six spaces. In all cases though you would still use a 30 amp breaker and #10 from the house.
 
  #7  
Old 03-31-13, 06:50 PM
Member
Thread Starter
Join Date: Mar 2013
Location: USA
Posts: 12
Received 0 Votes on 0 Posts
That would be fine with me. For some reason, I thought I'd have to use larger wire if I went to the 100 amp panel. It's definitely cheaper to use the 100 panel if I don't have to use larger wire.

Thanks!
 
  #8  
Old 03-31-13, 07:04 PM
ray2047's Avatar
Member
Join Date: Mar 2006
Location: USA
Posts: 33,597
Received 13 Votes on 11 Posts
The breaker is sized to protect the wire. The subpanel rating is simply the maximum current it is rated for.
 
  #9  
Old 04-08-13, 10:26 AM
Member
Thread Starter
Join Date: Mar 2013
Location: USA
Posts: 12
Received 0 Votes on 0 Posts
Hopefully last question...

I picked up a 100 amp, 6 space main for my box. My 4 rolls of #10 are getting in tomorrow. I'm looking to get the garage and conduit ready to pull. I have a couple of questions though. I'm going to use an LB box on the outside of the garage connected to my 1" conduit that will go down about 2 feet to the ground and then another 24" or so to the buried conduit. My garage walls are brick on the outside and 2x4 studs covered with drywall on the inside. Question is; where can I stop using conduit? Do i need to use conduit to connect from the LB box through the brick? If so, do i need to run conduit from that point through the wall behind the drywall to the main panel? Total length from leaving the ground outside, running up and through the wall, back over to main is like 6' of wire. I appreciate the help again!!

chi_town
 
  #10  
Old 04-08-13, 10:59 AM
ray2047's Avatar
Member
Join Date: Mar 2006
Location: USA
Posts: 33,597
Received 13 Votes on 11 Posts
Unless you transition to NM-b as you enter the garage it must be conduit all the way.

Assuming the panel is flush mounted I would cut an opening for a single gang old work box in the Sheetrock directly below the panel near the floor. It should be easy to drop a piece of 10-3 NM-b from the panel to the opening. I would use a LB conduit body on the outside. I would drill a hole for a threaded adapter in the back of a receptacle old work box and install the adapter in the back of the old work box with conduit nuts. Then install the old work box with a short length of conduit between the adapter in the back of the box and the LB outside. You can bring your individual conductors into the old work box and connect to the NM-b from the panel. Install a blank cover plate and your done.

Note: Use a press in cable clamp where your cable goes through the panel.
 
  #11  
Old 04-08-13, 01:45 PM
Member
Join Date: Mar 2006
Location: Wet side of Washington state.
Posts: 18,493
Received 33 Votes on 25 Posts
Rather than use a plastic "old work" box as Ray has described I would use two "gangable" steel boxes that already have the knockout in the back. Using two boxes ganged together gives you sufficient room to actually splice the wiring without possible volume (of the box) problems. Use boxes that have flanges and expansive bolts on the sides to allow it to be held in place and run a short green wire from the equipment ground splice to the steel box. Use a blank cover over the box.
 
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
 
Ask a Question
Question Title:
Description:
Your question will be posted in: