attempting to wire my new barn to my main breaker box.

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  #1  
Old 11-17-13, 09:20 PM
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attempting to wire my new barn to my main breaker box.

I am wanting to wire up my barn to my main box in my house. I have a 200 amp service in my house with plenty of extra breaker spaces. I have put in a siemens breaker box in the barn as well. Right now it has a 100 amp main breaker in it but I want to change it to a lower amperage, more like 40amp if possible. (I bought the whole box full of breakers for $40) My question is, I need to do the following things,



1. Determine the wire size. I am aware I need 4 conductor wire as I want to go ahead and wire for 220v. I don't know exact distance but I know it is around 75-100 ft away from main box. I will measure asap.

2. Do I use direct bury or use plastic conduit and put the wire in.

3. Do I need a grounding rod at the barn? if so I see copper and galvanized. About $5 difference in price, and what size wire do I need to go from grounding rod to barn breaker box.

4. As of now, the barn breaker box has a bar connecting the ground and the neutral wire. Do I keep it like this or remove the bar?

some pics I took and made up. The first pic breaker box has all the wires from the previous install still in it and is the one in the barn. I have taken out all wires since pic was taken.
 
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  #2  
Old 11-18-13, 04:17 AM
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Right now it has a 100 amp main breaker in it but I want to change it to a lower amperage, more like 40amp if possible.
Use the 100 amp main breaker as the panel(barn) disconnect. The 40A double pole breaker at the main will protect the whole system. The size of the main breaker at the barn is irrelevant.
1. Determine the wire size.
By luck, the wire size is the same, cable or pipe. For copper, #8 hot, hot and #10 for white and green. With exact specs I could calculate Voltage Drop, which might increase wire size. Needed, total amps of all projected loads to be used simultaneously and length of wire from main to sub.
2. Do I use direct bury or use plastic conduit and put the wire in.
Either, both are code compliant. Bury conduit 18" plus the dia. of the pipe. Bury cable 24" plus the dia. of the cable. I recommend protecting both with sch. 80 where above ground and to a depth of 18".
3. Do I need a grounding rod at the barn?
Two. Copper is better. It may take galvanized 10 or 20 years to rust away, but copper won't disappear in your lifetime. Cu. wires are, #4 if unprotected and #8 if protected in conduit.
4. As of now, the barn breaker box has a bar connecting the ground and the neutral wire. Do I keep it like this or remove the bar?*
I don't believe the bar is made to be removed. You're supposed to use a ground bar kit. The kit's part # is often listed on the panel's label. In either case the neutral bar needs to NOT be electrically connected to the can. I think I see a green bonding screw that needs to be removed. The ground bar needs to BE electrically connected to the can.
 

Last edited by Glennsparky; 11-18-13 at 04:45 AM.
  #3  
Old 11-24-13, 06:39 PM
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I have been checking around for wire, and came across what I hope will work tonight at lowes. They had some pre-cut wire. It is aluminum but is 2-2-2-4 alum mobl hm fdr. They guy in the electrical section at lowes said it was for mobile home feeder wire. I know copper is better, but I got a great deal on it at .66 a foot. I plan on putting it in grey electrical conduit from the house all the way to the barn.
 
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Old 11-24-13, 07:47 PM
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It is okay for outside use but if it is not rated RHH / RHW it can't be used in a structure. You will need to change to cable or wire rated for use in a structure if it isn't RHH/RHW. #2 is probably not going to fit a 40 amp breaker so you will need to change at the house anyway.
 
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Old 11-24-13, 08:03 PM
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it does saw RHH RHW 2 on it. I tried to measure it up, it looked like it would fit in the breaker, but I definitely could be wrong. I have not tried it yet. I did think about getting a small breaker box and coming off my main box right beside it to wire it in.. would that be redundant? I also thought about doing that for a generator sub panel. (a way to run a generator to a breaker box with a lockout system on it)
 
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Old 11-24-13, 08:57 PM
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did think about getting a small breaker box and coming off my main box right beside it to wire it in.. would that be redundant?
No need. You can connect to smaller wire if needed in the breaker box. Only the hots may need to be reduced. If there aren't holes large enough in the neutral bar you would use an adapter that uses two spaces.
 
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Old 11-24-13, 09:11 PM
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just went and looked at my box, looks like on the neutral bar, there is a large terminal that I can use. It has 2 neutral bars, one side has the large terminal coming from the service line and the other side is still open. The ground bar has no large terminals, but I was on lowes.com looking and saw the adapters that use 2 terminals...

what would be the best way to reduce the 2 hot wires?
 
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Old 11-24-13, 10:05 PM
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what would be the best way to reduce the 2 hot wires?
You splice them to smaller wires. Since the wires you splice to will probably be copper you will need special connectors. Such as split bolts that separate the aluminum and copper.
 

Last edited by ray2047; 11-25-13 at 04:35 AM.
  #9  
Old 11-24-13, 10:23 PM
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Smile

found it I think, maybe not the right size but right idea. ,, Shop IDEAL 2-Pack 2" Aluminum Split Bolts at Lowes.com

I am learning so much from this forum. I am still getting an electrician, just trying to learn all I can for any future projects.

I did car audio for over 18 years professionally and dealt with all kinds of wires, relays, etc, but ac has me baffled,,,,up until now.
 
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Old 11-25-13, 01:45 AM
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Mobile home feeder cable should also say USE and be identified for underground use. As such, conduit is not needed below 24 inches. Conduit, preferably sch. 80, is needed above ground and continued to a depth of 18".

Split bolts are old school, but still very useable. Usually the splice is wrapped with two layers of electrical tape, with a layer of friction tape in between.

Written on breakers and panel labels are specs for the lugs. Only conductors of the right size and type(AL/Cu) will fit legally. Torque specs should be followed, especially for AL, even though few electricians ever use a torque wrench. The wire should be wiggled while the fastener is torqued to spec.
 
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Old 11-28-13, 09:55 PM
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went and looked, and it does say "use" on the wire. I am going to use conduit regardless, I already bought it and it will protect that much more. I have called 3 different electricians to come out and give me an estimate, and you know not a single one has showed up. I was trying to read up some more on the connections. I totally understand the connections at the barn breaker box. I have 2 hots coming in at the top and then a bar on each side. One for the neutral and one for the ground. at this time it has a bar going from the neutral to the ground side which I know I need to remove. I will have 4 wires coming from my main breaker box. 2 hots from the breaker I install, 1 neutral and 1 ground. So I will have a total of 4 wires going from my main box to my barn. The 3 2 gauges for the hots and neutral, and 4 guage for the ground.

So if I am reading right, even though I am coming from my main breaker box with a ground all the way to the barn, I still need 2 grounding rods? And I would use #4 solid copper wire to connect the 2 rods to the grounding block of the box in the barn?

Just trying to get a good understanding since no electricians in my area seem to want any small jobs. I know they have hourly rates and I don't have a problem with that, but seems like they don't want anything that's only going to take and hour or so.

also found these for reducing the wire size down. Shop IDEAL 2-Count Wire Reducer Wire Connectors at Lowes.com
 
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Old 12-04-13, 01:21 AM
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Got it all wired up and working. Ended up doing it myself as to no electricians were interested in such a small job. Luckily my neighbor I the head of electrical and plumbing for a large company and he came and inspected everything before I turned power on. Everything works great. Thanks for all the help. After all that I learned, I ended up running a wire to my flagpole so I could add a light to it. Amazing what knowledge of a group can help with!
 
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Old 12-04-13, 05:28 AM
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Glad you got your project finished and all is well. Thanks for letting us know the outcome.
 
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