Wire for detach garage

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  #1  
Old 06-14-10, 05:36 AM
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Wire for detach garage

Hello,
I am going to be building a 24x24 detach garage. I would like to pull a line from my house to the garage.

What size line should I pull and what type?

What size breaker in the house panel would i use?

How deep would I bury the line in the ground?

My house has 200 amp service and my intent for the garage is to some day in the near future to do some of my woodworking i like. this could be in the winter as well so electric heat may be needed if possible.

Any help you could provide would be appreciated. Thanks.
 
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Old 06-14-10, 05:50 AM
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The first step is to determine how much electric you will need in the workshop. Once you get those answers you can figure out your breaker and wire sizing.
 
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Old 06-14-10, 06:07 AM
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Thanks for the reply.

Can you give me some tips on determining that?

When I think about it now, the small shop i have in my garage if my table-saw and dust collection are plugged into a single 20 amp circuit and there is something else drawing a moderate amount of power it will trip the breaker. Ideally these would be on separate circuits. Is this what you are thinking i need to determine?
 
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Old 06-14-10, 07:18 AM
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Yes, that is what I was asking about. If you are only going to be using a dust collector and one machine at a time there is a good chance that a panel fed by a 60 amp breaker would be plenty to serve your needs.
 
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Old 06-14-10, 07:28 AM
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When I think about it I think it would be ideal to have the following:

1 - table-saw (2hp i believe. jet contractor saw)
2 - heat/air conditioning
3 - dust collection
4 - lights
5 - empty
6 - empty

all on there own 20 amp circuits. I would alternate the outlets in the garage to have every other one be on one of 2 circuits.

I was thinking of 50 amp sub panel in the garage would be sufficient. Maybe this isn't enough?
 
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Old 06-14-10, 07:31 AM
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What size HVAC setup are you thinking about?
 
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Old 06-14-10, 07:42 AM
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you must have replied while i was typing.

So a 60amp breaker what gauge wire do i need? 8 gauge?

when i bury this do you run this through some conduit of some sorts underground?
 
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Old 06-14-10, 07:46 AM
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I haven't decided on what type of heater I would get. I had thought about one of those units that mounts in the upper corner of a garage. I am not sure what size i would need for a 24x24 area. I would only need it to maintain 60 degrees or so in there, but it does get cold in our area (ND). I have a small window AC unit that I have never used that says will cool 1000sq feet and i would just use that in the summer as needed.
 
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Old 06-14-10, 08:44 AM
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Will you be using electric heat or a gas/propane unit?
 
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Old 06-14-10, 08:54 AM
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I would like to use electric heat so I don't have to try and get a gas line out there.
 
  #11  
Old 06-14-10, 09:02 PM
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a 50 amp sub will give technically give you 100 amps at 120 volts..... so it would be plenty big but you might as well get a 60 amp panel feed it with 6 gauge copper or 2 gauge alum put it on a 60 amp breaker

even with a 30 amp heater(220volts) you would still have 60 amps available for 125v appliances at a peak load. I dont think you would exceed 80 percent.

Now if your thinking of a welder or many 220 volt appliances you may want to go bigger...
 
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Old 06-15-10, 05:15 AM
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Thanks for the response. That sounds good and that is what I will do. Any specifics I should know when pulling this in the ground?
 
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Old 06-15-10, 05:58 AM
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A couple of things; the conductors must be rated for a wet environement. These are typically THWN. You will need 4 conductors, 2 black hots, a white neutral and a green ground. The ground can be a #10.

If you bury conduit it must be 18" or deeper to the top of the conduit. You can fit it in 3/4" but I might go with 1" to make it a little easier.

You will also need a grounding electrode system like 2 8' rods driven no closer than 6' apart.

I am also linking to the sticky for subpanels.

http://forum.doityourself.com/electr...-drawings.html
 
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Old 09-02-10, 12:31 PM
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One more question. When looking at the diagram you sent it looks like i should go with the 2-2-2-4 to comply with code.
I have a guy at the home store saying i am fine with 2-2-4 but he is no electrician he kept reminding me. I would love to go with the 2-2-4 as it is half the price a foot but i want to be sure and comply with code.

Thanks again for the help. I know this is a bit older of a thread.
 
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Old 09-02-10, 12:50 PM
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Under the 08 NEC you are no longer allowed to run a 3 wire feeder to an outbuilding. The new requirement is for a 4 wire feeder.

You also could not use the older 3 wire feeder if there were any metallic paths between the building prior to the 08 NEC.
 
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Old 11-01-10, 11:39 AM
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To continue with this threat. I am looking at the sub panel I have and i want to validate since i have not hooked up a 4 conductor cable of this size.

There is a single bar on either size which is connected by a bridge (not sure the actual technical name) that can be disengaged via a screw. On the one side there is a location to connect one of the wires.

Using 4 conductor wire I believe I need to disengadget that bridge and bring the ground from outside to the one bar as well as the ground from the wire. In addition i will then ground all circuits to this bridge as well. The opposite will be the neutral bar where I will likewise connect the circuits and the wire correct?

Finally, the one bar does not have a spot to connect a wire the size of 2 gauge but the other does. Is there an adapter that one needs to get to connect the 2 gauge wire to the bar?

Thanks again for the help and slowly but surely I am getting there. Daylight savings time next week and I am going to need some light to work in there after 8-5 hours.
 
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Old 11-01-10, 11:47 AM
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Originally Posted by bline22 View Post
I believe I need to disengadget that bridge
Correct, you generally remove that bonding screw and sometimes need to remove the bonding strap too. The panel instructions usually say how to do it. Some panels you just need to buy an add-on ground bar kit which will mount to tapped holes in the panel gutter space.

bring the ground from outside to the one bar as well as the ground from the wire.
The GEC (wire to ground rods) and the EGC (green/bare wire from house) both go to the bar which is solidly connected to the metal panel box. The bare/green grounds from your branch circuits also go to this bar.

The other bar in the panel should be separated from the metal box with plastic standoffs. The white neutral wires go here.

Finally, the one bar does not have a spot to connect a wire the size of 2 gauge but the other does. Is there an adapter that one needs to get to connect the 2 gauge wire to the bar?
The neutral bar should have a large lug for the feeder neutral. The ground wires should be smaller than #2 so it should fit okay on the ground bar. If not, you can buy a larger lug kit that bolts onto the bar for a few bucks.
 
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Old 11-01-10, 12:29 PM
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I see that I said to continue with this threat. I meant thread there. My bad. I sure had some fat fingers when I read it again. Should have proofed better before hitting submit. not my strong suite.

Thanks for the response and I will take a peak. I am sure I will have a couple of further questions on this as I get into it more.
 
  #19  
Old 11-02-10, 06:09 AM
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The wire I am using is 2-2-2-4. I can tell which is the 4 (ground) easily with the line denoting that wire. Any quick tricks of the trade in determining which wire is which as the others are all black?
 
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Old 11-02-10, 07:12 AM
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Originally Posted by bline22 View Post
The wire I am using is 2-2-2-4. I can tell which is the 4 (ground) easily with the line denoting that wire. Any quick tricks of the trade in determining which wire is which as the others are all black?
Is there a raised rib or stripe on one of the wires? Why are you using such large wire for a 60a run? Exactly what kind is it?
 
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Old 11-02-10, 07:18 AM
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The neutral should have a stripe on the insulation that is not red or black. Typically it will be white or yellow.
 
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Old 11-02-10, 05:12 PM
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If the three #2 conductors are identical then connect two of them together at one end and use a continuity tester at the other end to find the two that show continuity. Mark the third wire with white plastic tape on each end.
 
  #23  
Old 11-03-10, 06:03 AM
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I had to run home first to verify before responding yesterday.

All the 2 gauge stuff has no indicator stripes or anything else on it. it is solid black. The 4 gauge wire has the yellow stripe but I would have thought that was the ground? I bought the wire from an electric supply company here in town, Border States Electric so it is not something i got off of craigslist or anything like that.
 
  #24  
Old 11-03-10, 06:54 AM
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Sorry Furd, Missed your response. Thanks. I will give that a whirl.

Now just to get my flexible conduit and connectors which everyone is somehow out of here in town. The one connector type they have from one brand is 6 a piece and the other is 19. They have the $19 one. That is nuts and I think I need 4 of them.
 
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