Electric line to garage

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Old 08-19-16, 08:43 PM
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Electric line to garage

Hello. Im new to this forum. Looking for some guidance on running electric to a new garage on my property. Id like to think my electrical skills are pretty good, and Ive run lots of electric in the past. However, Ive never ran a new main to a building. It is a 280 run from the house electric panel to the garage. This is the wire that I planned to order. 2-2-2-4 Aluminum quad dyke. (southwire quadruplex URD).

What do you think? It is cost effective and I think it will do the job. 50 or 60A is what Id like to use for this circuit. Ive never seen this wire, but I assume there are two 2AWG wires for the hot, another 2AWG wire for the neutral, and a 4AWG for ground. Does that sound correct? I have some other questions as far as the breaker, GFI but I figured Id start with the wire and figure that out first. Thanks!
 
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Old 08-19-16, 10:14 PM
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It would be a good choice. Note it does not appear to be dual rated so it could not be used inside. You would need to transitions to something such as 6-3 NM-b where it enters the building. You could bring conduit up into a 4x4 box mounted on the outside and run the NM-b into the back of the box from the inside.

You would need a panel in the garage. A 100 amp main breaker panel kit is usually the most economical way to go. The 100 amp breaker is used as the code required disconnect (six throw rule). Even if you don't have six circuits and need a disconnect it is still an economical way to go since the kit includes some branch circuit breakers. You will also need to buy and install a ground bar to the panel. At least one eight foot ground rod is also needed (AHJ may require two).

Your voltage drop at 50 amps would be 3.7 amp so You could use a 60 amp breaker in the main panel no problem.
 
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Old 08-20-16, 06:02 AM
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Thanks Ray. That's very helpful info. The 100Amp breaker kit and grounding rod at the new garage makes sense to me (I didn't know there has to be another ground). I also had not thought of putting a main breaker out there.
The 60 amp double at the house....does that have to be GFI?
The transitioning of the wire to inside wire has be a little confused but I'll research that with southwire and see what they have to say about that. Thanks
 
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Old 08-20-16, 07:41 AM
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You'll only bring your "outside" wire to the main breaker. All the "inside" wiring will be from your individual breakers. Unless there was a UFER installed when the pad was poured, you may need two grounding rods spaced at 8', but check first to save some work. A UFER is a copper conductor embedded in the concrete as the pour is made with a "pigtail" left to connect to your grounding system. The last garage I built for a client had a UFER so I only had to install one rod.
 
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Old 08-20-16, 08:45 AM
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Thanks. The grounding thing should be no problem. I have a demo drill that has a ground rod pounder on it so I can put a couple of those in with ease. I understand that the inside wiring to the outlets is different wire 12 or 14awg...but I think Ray was saying my service wire could not be used to enter the house. That was news to me.
 
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Old 08-20-16, 01:02 PM
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Ray was saying my service wire could not be used to enter the house.
Or into the garage. If there are no markings on the individual wires of the URD such as THWN or XHHW then the individual conductors are not rated for use inside buildings. Dual rated there would be markings like THWN or XHHW which are types of wire used inside. Note even if dual rated it must be in conduit inside.
 
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Old 08-20-16, 07:09 PM
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gfi

The 60Amp in the house...does it need to be GFI or is that not required?
Thanks?
 
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Old 08-20-16, 07:55 PM
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No GFCI is required at the house. Receptacle circuits in the garage will require GFCI protection but not lighting or most 240 volt circuits.
 
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Old 08-21-16, 02:15 PM
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Southwire's Aluminum Quadruplex (Dyke) only carries a USE-2 insulation rating and by the NEC USE-2 only insulated wire is not to enter the structure, it has to be terminated outside. You can use Mobile Home Feeder (MHF) which carries a rating of RHH/RHW-2/USE-2. The additional ratings are flame resistance. USE-2 alone is not flame resistant.
 
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Old 08-21-16, 06:53 PM
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Thanks for all the help. Now I know what I need to order. Just to verify...this wire is 2-2-2-4....and the 4AWG wire is ground, right? It doesn't cause any issues with connecting the 2 grounds together at different locations? My house has ground, and I will be adding ground rods to the garage panel...and they will all be tied together. Somewhere, someone told me something about not doing this at some point in my life I thought.
 
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Old 08-21-16, 07:49 PM
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You need a grounding system at both buildings.
 
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Old 08-22-16, 08:35 AM
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The #4 wire in the 2-2-2-4 feeder is the ground wire and is called an equipment ground. The earth ground system is the rods connected by the electrode ground conductor. The two are different animals and serve two different purposes. The house grounding electrode system and the detached garage grounding electrode system are to be two separate systems. But technically the grounds from both the house and garage are bonded together via the equipment ground running between the structures. The main purpose of the grounding electrode system is to divert lighting strikes. The equipment ground is to handle faults.
 
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Old 09-03-16, 05:47 PM
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wrong wire?

Thanks Pattenp. I think after I read that I realized I have the wrong wire selected. THe wire I was going to get is probably better for 3 phase right? I'm thinking what I need is a 2-2-4 NOT a 2-2-2-4
Could someone please verify that I'm correct please. The good news is, I didnt order anything yet and this wire is a little cheaper. This is the link:
(By-the-Foot) 2-2-4 Black Stranded Al Stephens URD Cable
 
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Old 09-03-16, 05:58 PM
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THe wire I was going to get is probably better for 3 phase right? I'm thinking what I need is a 2-2-4 NOT a 2-2-2-4
Wrong. You need four conductors for a single phase subpanel (L1, L2, N, G).
 
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Old 09-03-16, 06:07 PM
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OK Ray, that's what I was thinking originally. I guess the last post confused me a bit. The "4" is ground that ties the two together then. In some sort of way, the neutral is kinda sorta a ground and I thought that's what he was talking about that was tied together. It doesn't matter. I need to hook the L1 and L2 to the hot side of the breaker, the other 2AWG to the neutral (white) and the final 4 awg to the ground bar on both panels. If that's wrong, I'm more confused than I was before but please let me know. Thanks
 
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Old 09-03-16, 07:48 PM
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You have it correct. The neutral is actually used to derive 120 volts from either L1 or L2. It us the center tap on the secondary of the transformer that supplies 240 volts to your house. Confusion comes from the neutral being the grounded conductor but the actual ground (GEC) serves a very different purpose. It is to rapidly clear faults by tripping the breaker.
 
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Old 09-04-16, 06:29 AM
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Remember if this wire is being run inside of the house or garage it cannot be URD which is marked as only USE-2. You need to use wire which is marked as THWN-2 or XHHW-2 or RHW-2 to be run within the structure.
 
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Old 09-04-16, 06:58 AM
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Thanks guys. I'm clear on the wire configuration now. There was some discussion about that wire being used inside on the HomeDepot site. It sounds like southwire was telling one guy it's not ok to run it across the house but told another it was ok to terminate it to the panel directly. In my case, the panel is directly on the other side of the wall, so I have just a foot or 2 of inside wire. I was going to order it and see what it looks like, not even sure if it can be terminated directly to the C/B and bar (not sure of the flexibility or gauge will work). I can do what you suggested and put a box on the outside I can find some sort of terminal lugs or something. Is there a better wire I should be ordering to do this 280' run maybe? Thanks
 
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Old 09-04-16, 08:48 AM
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My suggestion is to use 2-2-2-4 Mobile Home Feeder (MHF) the insulation rating is RHH/RHW-2/USE-2 and can be run inside the structure. The #2 is the absolute smallest wire you will want to use for a 60 amp feed at 280 feet because of voltage drop. At a 40A load the VD will be about 3%, at 50A 3.8%, at 60A 4.5%. No more than 3% is recommended, but 5% is the max. The #2 will fit a 60A breaker and should also fit a 50A breaker. The wire size a breaker will take is stamped on the breaker.

Edit: I forgot to say the MHF is direct bury if you don't want to run conduit underground. But conduit is best for physical protection. It does have to be in conduit where above ground and inside the structure.
 
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Old 09-04-16, 05:09 PM
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Thanks Patten. Sorry to keep this thread going so long. I think I found something that should work and the price is almost too good. What do you think?

2-2-2-4 ALUMINUM MOBILE HOME FEEDER CABLE
 
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Old 09-05-16, 06:24 AM
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That is what you need and is a very good price as long as shipping is reasonable. Also take note the web page says 100A but that is only when used as a full service to a dwelling. When used as a branch feeder #2 Al is limited to 90A. If cost ends up being less $1.50 a foot with shipping it's a good price.
 
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Old 09-05-16, 06:39 AM
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Thanks for verifying to wire. Now I can be confident it's correct. Shipping is fair, as it only added about .20 per foot.
 
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Old 10-12-16, 05:17 PM
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one more thing...

So I'm back. Thanks for all the help. I have buried the wire and purchased the panel and C/B. One last thing I want to verify:
On the new sub panel, there is a neutral bar of course on both sides. I'm a little unsure about this ground bar thing. I figure I just connect the neutrals, the ground from the main panel (in house), and the ground rod all to the same neutral/ground bar? That's how it seems to be in my main panel (house). Thanks
 
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Old 10-12-16, 06:06 PM
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No. The ground and neutral get connected to the same place in the main panel. (Make sure it is your main panel) The sub panel the ground and neutral are kept separate.

The green screw that came with your panel is left out. The ground bar(s) get connected as shown in the picture. You will see some screw holes that line up if you bought Square D bar(s). The neutral wire gets connected to the neutral bar. The ground and grounding electrode conductor (ground rod wire) get connected to a ground bar.

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Old 10-12-16, 06:58 PM
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Thanks! You even answered a question that I didnt ask...you're good. (I was wondering about the green box bonding screw). Now I know not to use it.
I'll see what I can find at HD that will work in this Square D/Homeline box. So I really need (3) of them...or is that just the three different optional locations I can put them?
 
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Old 10-13-16, 07:03 AM
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You only need one ground bar. The picture is showing options of where it can be located.
 
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Old 10-13-16, 10:59 AM
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Got it. Thank for the help!
 
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Old 10-16-16, 06:32 PM
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verify

All hooked up and it works! I wanted to verify something....I have a ground bar added in the sub panel (like you directed me to do). I have the ground rod and ground from the main hooked there, like you said. Now...the grounds from the individual circuits go there too, right? Not on the neutral bar. I have one circuit that goes to my compressor, 220. I have tied the ground to the ground bar. I'm guessing it would work even if I put it on the neutral, but I'd like to make sure it's correct. There are probably more than one way to do it, but only one correct way. Please let me know. Thanks
 
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Old 10-16-16, 07:12 PM
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Now...the grounds from the individual circuits go there too, right?
Yes, that is correct.
I have one circuit that goes to my compressor, 220.
Nominal voltage is 240 not 220.
I have tied the ground to the ground bar. I'm guessing it would work even if I put it on the neutral, but I'd like to make sure it's correct.
The ground is for safety not function. The compressor will work even with no ground but to meet code and safety it must be connected to the ground bar.
 
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Old 10-16-16, 07:33 PM
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Thanks for the speedy reply and clarifying all that. I think I'm good to go now!
 
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