2-2-2-4 extra ground?

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  #1  
Old 07-23-04, 05:50 PM
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2-2-2-4 extra ground?

I finally got the UB cable for the shop. Code says 2-2-4 aluminum is OK but the only wire they had at Lowes was 2-2-2-4. I'm familiar with how to wire service with 3 wires but what do I do with this extra wire? Is it supposed to wire onto the regular neutral bar?
The wire is made for mobile homes which probably have different requirements but I paid for the extra wire so I'm gonna use it. Probably can't have too many grounds..
Thanks.
I forgot to mention that it's going from a 100 amp breaker on the house to a breaker box in the shop. I have a 220 v welder and a 22o v compressor but mostly just lights and hand tools.
 
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Old 07-23-04, 09:03 PM
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Yes you certainly do need that extra wire.
Subpanels must have the grounding isolated from the neutral. The subpanel must have a seperate grounding buss installed, and if there is a screw bonding the neutral buss to the frame, remove it. The #4 wire would be bare/green, and connect to the grounding buss. There are many previous posts on thus topic of subpanels in garages/barns/sheds/etc. and the appropriate requirements for grounding rods and similar issues.

If the new cable is aluminum, be sure to get a bottle of the anti-oxident goup for aluminum wires and work it in before terminating them. Try not to get it on your skin though.

If you need more details about the hookups, ask. The idea behind the isolation is to prevent a current on the grounding system where such current should not be due to backfeed.

gj
 
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Old 07-24-04, 01:36 PM
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Thanks GJ. I'm still a little lost. My trusty electrical book is dated 1971
I have a regular GE 100 amp breaker box in the shop with my cable running to my main service on the side of the house where I'm going to mount a 100 amp breaker. I guess it won't hurt anything to have a main breaker in the shop and one on the house.
My breaker box in the shop has 2 ground buses on either side with a removable bar. Do I hook up the regular neutral to one bar and the big green ground to the other and hook all my bare wire circuits to the bar with the green ground? Then what do I do with the other end? I've buried the whole shebang so now I have 4 wires at the disconnect breaker on the house. I'm kinda confused because if it's just gonna hook to the ground rod then why did I string wire 50 feet underground from the shop to the house?
I hope this makes sense...
 
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Old 07-24-04, 08:11 PM
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As I have learned from asking questions & reading a lot of these posts, you absolutley need a ground wire between each of your panels, as well as ground rods. They each serve thier own seperate purposes. Your main panel will have the ground wire and the neutral wires bonded. That is the only place this will occur. In your sub panel, all your ground wires from the circuits therein will be joined on a bar, (bonded to the panel), connected to the green (or bare) ground wire coming from your main panel (where it is joined to the ground bar that grounds your main panel). The neutral (white) wires in your sub panel will be joined on a different bar (that is not bonded to the cabinet), connected to the white wire coming from your main panel. In other words, at the disconnect breaker in your house, you'll have two hots to the breakers (one for each phase), one neutral (white) that will connect to the bar that has all the other whites, and one ground (bare or green) that will connect to the bar that has the other bare grounds connected (which may or may not be the same bar the whites are connected to). A ground rod will have to be connected to the ground bar in the sub panel, as well.
 
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Old 07-26-04, 10:51 AM
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Talking

Thanks for the replies. I think one problem I have is with terminology. My shop wiring is coming off the 2nd set of load lugs on my meter base. (The 1st set of load lugs will go to the disconnect that feeds the house.)
I'll have wires from the meter base --- to a single 100 amp breaker on the side of the house -- 50 feet underground --- to an 100 amp breaker box, or load center, not sure what to call it....
Where I get confused is which is my "main panel" and which is my "sub panel"
I have my permit and I need to have everything together when I schedule the outage.
My wife wants me alive and the AC running when she gets home from work that day
Thanks for the help. I don't think I'm as dumb as I sound but I could be wrong...
 
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Old 07-26-04, 12:36 PM
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If a subpanel is intended only to feed 240 volt only loads (e.g. none of the loads uses a neutral wire), then why would you need to have a neutral wire at all?
 
  #7  
Old 07-26-04, 02:47 PM
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Re; main and sub panel confusion; The electrical inspector gave me his definition this way: If there is a disconnect breaker under the meter, that technically is the main panel; all others are sub panels.(The main panel being the first breakers on the customers side of the meter.) If there are double luggs at the meter, then you could have two "mains", and there are rules governing that situation, as well.The service wires run from the meter into the disconnect (main) panel, and the ground rod, neutral wire, and equipment ground all connect together at that point. At all other panels being fed from this one, ground and neutral wires must both be run along with the power wires. At all sub panels, ground wires and neutral wires must be kept separate from each other (all grounds on one bar, bonded electrially to the panel, all whites on another bar, insulated from the panels).
I assume this is explained in more technical terms in the codes, but this is a laymen's interpretation.
 
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Old 07-26-04, 03:47 PM
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Thanks H-D.
In the box in the shop:
I need to put a ground lug (Let's say on the left side grounding deal with all the screws down the length) and remove the bonding strap and put the bonding screw in and connect my big green ground to that. Then hook my neutral up to the grounding deal on the right side of the box. (This one already has a lug to accept the big #2 neutral) Then all my grounds from the circuits will go to the green wire and all my neutrals will go on the neutral side.
In the box on the house:
The neutral and big green ground will tie in. (There is 3rd lug between the load and line lugs.
I hope I understand.
By the way, I'm a Ural Rider. (Russian motorcycle)
 
  #9  
Old 07-27-04, 05:10 AM
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This sounds right to me, but I'm sure one of the many pro's will chime in if there's something amiss. Earlier you said that you had double luggs on your meter (not on a disconnect, but rather the customer side of the meter itself)that you could tap in to... That would make whatever panel that connects directly to this set of luggs a "main" as well, and I know there are some rules for that situation, but I don't have them at my disposal. Pending any suggestions from the real pro's, I'd treat the first breaker panel attached to those luggs the same as I would if it were the only "main"; neutral & ground bonded, connected to equipment ground and ground rods. If this is incorrect, I'll take a beating from the pro's on this, I'm sure.
Seen a Ural up close only once... did yours come with the sidehack?
 
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Old 07-27-04, 08:09 PM
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Thanks. I think I have a handle on it. Yep, the Ural has a chair although it's off right now so I can ride solo. I'm surprised you've heard of them. It's not your average, everyday scooter
 
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