Running cable to a detached garage

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  #1  
Old 07-02-08, 08:28 AM
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Running cable to a detached garage

Just trying to get some insight as to specific requirements for running cable to my detached garage. I'm not planning to use the garage for something more than storage and small power tools...no need for me to go really crazy wiring it. my real reason is that it's not done correctly. Witout going into too many details, let's just say that whatever "conduit" they used years ago, is firmly cemented in at the base of the garage in what looks like a large clump of concrete. i want to redo it the right way plus take it off of a shared circuit. I would like to have it be its own dedicated line...

I currently have a brick house. I want to run cable from my panel inside my house to my garage thru my basement. Most of the basement is finished with a ceiling, etc. So, my access is somewhat limited. My house is "balloon framed" so it's not tough to put a hole into the brick and drop a line into the house. What is difficult is putting in a box behind that wall, so take make it easier on me, I decided to use the UF cable. Here's where my questions come in.

I'm assuming it's ok to run "normal" cable to a junction box and secure it a foot or so away from the end of the joist and then run the UF Cable though the opening between the studs and out the hole to the outside. I'm going to wrap some extra cable inside in the event I ever need it. But, do I have to have a break in the cable in the LB fitting?

I was thinking that I would just run the cable thru the LB then thru conduit and bury it in a 24" trench.


Is there a requirement as to how much off of the ground the LB has to be? I have noticed that it's around 24" or so... but I wanted to know if there was anything in the code that specified it. Or perhaps I could get a recommendation as to how high to make it.

Maybe I'm looking at this all wrong and someone thinks that i can do this a better way... I'm open to listening.

Thanks
 
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Old 07-02-08, 08:53 AM
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i want to redo it the right way
You have presented no information that would lead us to believe that it was originally done the wrong way.

take it off of a shared circuit
Probably a good idea.

I'm not planning to use the garage for something more than storage and small power tools...no need for me to go really crazy wiring it
It is important to as much as possible to accurately predict your future needs. That's because the code only allows one feeder to a detached structure, and if you later find that you don't have enough power, you'll have to abandon everything you do now.

I'm assuming it's ok to run "normal" cable to a junction box and secure it a foot or so away from the end of the joist and then run the UF Cable though the opening between the studs and out the hole to the outside
Yes, that's okay. Run conduit through the "hole" to protect the UF cable. If the other side of the "hole" is above ground, then continue the conduit until the cable reaches the bottom of the trench.

But, do I have to have a break in the cable in the LB fitting?
No.

I was thinking that I would just run the cable thru the LB then thru conduit and bury it in a 24" trench.
Burial depth requirements vary depending on a variety of factors, but 24" is deep enough for anything.

Is there a requirement as to how much off of the ground the LB has to be?
No. It can even be underground if you want (but you don't want). Your main consideration is water penetration into the basement, so mount it above the snow line.
 
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Old 07-02-08, 09:02 AM
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Originally Posted by miwankiw View Post
I decided to use the UF cable.
UF-B cable is a good selection to meet your needs based on your description. I recommend that you use #12/3g UF-B cable to supply a 20A multi-wire circuit to the garage. This is effectively two 20A 120V circuits in one cable. You can also use it for light 240V loads. If you're interested in this idea, please post back so we can give you more details on the multi-wire circuit.

I'm assuming it's ok to run "normal" cable to a junction box and secure it a foot or so away from the end of the joist and then run the UF Cable though the opening between the studs and out the hole to the outside.
If by normal you mean NM-B "Romex" cable, yes. The splice point between NM and UF needs to be in a permanently accessible junction box. You can also just run the UF indoors too; the price is not that different between the two.

I'm going to wrap some extra cable inside in the event I ever need it. But, do I have to have a break in the cable in the LB fitting?
That's pretty much okay as long as the excess cable is not hanging loose so as to be used a clothsline or something like that. It needs to be secured. It's actually preferred that you do not have splices in an LB.

I was thinking that I would just run the cable thru the LB then thru conduit and bury it in a 24" trench.
That's okay. You only need conduit from the LB down to the bottom of the trench, then a 90 sweep to horizontal. The cable can be buried directly for the horizontal portion.

Is there a requirement as to how much off of the ground the LB has to be?
No requirement.

Additional comments:

* All outlets (lights + receptacles) must be GFCI protected in the garage.

* The first junction box which the cable enters in the garage needs to have a disconnect switch on the hot wire(s) to act as a building disconnect.
 
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Old 07-02-08, 11:02 AM
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Thanks John and ibpooks.
I actually have considered running 12/3.. for the larger load capacity and effectively giving me 2 circuits. I also was considering running a 12/3 for a 3 way light. My wife would like to have sconces on the front of the garage... I would like to have the ability to turn them on/off from inside the garage or house. Should I use a 1" conduit if I end up running 2 - 12/3's UF's? or will a 3/4" be ok?

Now that I'm thinking about that...here's a question. Can 1 large junction box house 2 lines. So, what I'm talking about is with respect to having 2 12/3's. I want to run 2 NM cables as far as I can inside my house...then switch over to UF. Can I have 2 connections within 1 large junction box?

With regards to this comment...

* The first junction box which the cable enters in the garage needs to have a disconnect switch on the hot wire(s) to act as a building disconnect.

I actually read about the 2nd point early before and I put in a master kill switch as my first junction. If I were to go 12/3, would i then just have 2 switches... I would think that's the simplest approach.
 
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Old 07-02-08, 06:04 PM
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If you use UF cable, you don't need conduit at all for the horizontal part (as ibpooks said). If you're talking about the above-ground and vertical portions, then you can use any conduit in which the cable comfortably fits.
 
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Old 07-03-08, 12:18 AM
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If you going to use the 12-2W/G UF cable my suggest size is 3/4 inch PVC is the min size.[ yeah you can use the half inch size but it will be mite tight and may have some issue to pull it in ]

But however if you use 12-3W/G UF if this one a flat type you have no choice but use 3/4 inch or larger PVC conduct. Not very often I will see a round 12-3w/g Uf cable but I belive there is one on market.

Otherwise Both Ibpooks and John Nelson is pretty much on the target with the wireing question there.

Merci,Marc
 
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Old 07-03-08, 10:38 AM
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FWIW, around here, in Canada, all 3w+G wire is round.
 
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Old 07-03-08, 05:21 PM
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Thanks Classicsat for updated info related to the wires you have in Canada area so I will keep a note in my mind when that popped up again.

Merci,Marc
 
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