Running power to workshop/ shed

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  #1  
Old 04-04-15, 05:48 PM
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Running power to workshop/ shed

Hi, I was wanting to run power to my outside work shop which is about 100 feet from my house. I am thinking the best way to do this is to run a 10/3 UF wire from a 30 amp double breaker from my existing 200 amp service in my house. I have been doing some research and I came to the conclusion that I should bury the wire 18 inches in the ground through conduit. Is this correct? Or would hanging it be easier? The main thing that has me stumped is what should I put in the shed? A small breaker box? I couldn't find any 60 amp breaker boxes.... The types of things I'll be running is a 220 air compressor (not very often), a few 110 power tools, and lights. Nothing to major really. Feel free to send me links to a breaker box I would need in the shed or anything else I would need. Any information is greatly appreciated.
 
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  #2  
Old 04-04-15, 06:19 PM
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to do this is to run a 10/3 UF wire from a 30 amp double breaker....I came to the conclusion that I should bury the wire 18 inches in the ground through conduit
Best practice to not run cable in conduit (difficult to pull). Best to use individual conductors such as THWN.
what should I put in the shed? A small breaker box? I couldn't find any 60 amp breaker boxes
A main breaker 100 amp, 12 space box should be fine. (The 100 amp breaker is only used as the code required disconnect). You will need to add a ground bar to the panel and drive one or two ground rods at the shed.

What is the FLA of the compressor?
 
  #3  
Old 04-04-15, 06:40 PM
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I am not sure what the FLA of the compressor is I will have to check tomorrow. It is just a craftsman 6hp oiless compressor, nothing to major. If I buy a 100 amp breaker box new from lowes, doesn't it already have a ground bar in it? What all goes into hanging 10-3 UF wire?
 
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Old 04-04-15, 07:16 PM
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If you want to run overhead with type UF then you need to use UF that also has UV (ultraviolet) inhibitors or the outer jacket will be destroyed by sunlight in about a year. You will likely need a pole in between the house and the shop unless you have a tall enough house (two story) to ensure that the lowest point of the cable is at least ten feet above the ground, fourteen feet if it crosses a driveway. Since type UF is not really meant to be run overhead you will probably also need to use a "messenger" cable, best would be something like 100 pound test stainless steel "downrigger" cable and fasten the UF to it every ten feet or so. Obviously the fasteners will need to be weatherproof and be able to withstand the UV sunlight.

OR, you could just trench a minimum of 24 inches deep and run the UF without conduit except using PVC conduit where the cable enters and exits the earth, just for protection. I would use a minimum of one inch conduit for this with a 90[SUP]o[/SUP] degree bend at the bottom of the trench and an LB fitting to go through the wall.

However, I would prefer to run no less than 3/4 inch conduit the entire run and then use type THHN/THWN individual conductors, probably no less than #8 copper for the two hot leads plus the neutral with a #10 for the equipment ground. Part of the reason for this suggestion is that I absolutely detest working with UF and secondly, a 30 ampere feeder is really small, especially to a shop.
 
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Old 04-04-15, 07:34 PM
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doesn't it already have a ground bar in it
No. It only has a neutral bar. In a subpanel grounds are connected to a bonded ground bar and neutral to an isolated neutral bar. Furd's suggestion of 40 amps is a good one. I considered suggesting it but was waiting for the FLA of the compressor.


 
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Old 04-04-15, 07:41 PM
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If I buy a 100 amp breaker box new from lowes, doesn't it already have a ground bar in it?
Most panels sold at box stores probably won't have a ground bar, but they should sell ground bars as accessories.
 
  #7  
Old 04-04-15, 07:41 PM
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Thanks for all the information so far. Seems this project is going to be pricey, definitely if I use 8 gauge wire like you're recommending. Let me ask this.... There is a power line that runs about 10 feet from my shed that all my neighbors have there 100 amp garages running off of. Would I be better off putting up a pole at my shed with a meter socket and outside breaker on the pole. Then run 100 amp mobile home feeder into the shed to a breaker box? Then call my power company and have them wire me in a separate 100 amp service.
 

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  #8  
Old 04-04-15, 10:24 PM
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Generally having a second meter also means having a second account with the utility which subjects you to another bill with minimum billing. Your utility may be different, you will have to call them for more information.
 
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Old 04-05-15, 07:29 AM
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Note all wire sizes mentioned assume a distance of less than 100 feet. It almost sounds greater from your last post.
 
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Old 04-06-15, 02:17 PM
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Ok, I think I am going to go with the separate 100 amp service. I called my electric company and they said I do all the pole work myself or have someone do it. Then they come out and run the wire from their main line to the top of my pole. The minimum bill for the separate service is only 13 dollars so I figure that's not bad. So this is where I need advice. I need to install my own pole right beside my building. On that pole I need to run the 100 amp leads from the top of the pole in conduit down to a meter socket then from the meter socket down to a shut off. Then from the bottom of the shut off I need to go to the bottom of the pole then elbow right into my building where there will be a breaker box. Does this sound right? I was wondering if someone could show me picture or maybe a link to a shut off box for on the pole and a meter socket. I will also need a copper ground rod I am assuming. I am thinking about starting this project this weekend.
 
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Old 04-06-15, 03:12 PM
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Everything you ask will be stated clearly in the Requirements for Service that will be provided by your power company. It may be available from their website as well. Depending on your LOCAL jurisdiction you may (most likely will) need an electrical permit for a new SERVICE from your local building department or code enforcement office.

It is impossible to give anything but generic advice here because we do not know the LOCAL requirements nor the power company requirements. These local requirements rarely allow for major substitutions.
 
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Old 04-06-15, 03:46 PM
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IMO setting a 100 amp service is overkill for the limited loads you described. Add in the recurring costs every month and I just don't see it as economical.
 
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Old 04-06-15, 03:52 PM
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Would I be better off putting up a pole at my shed with a meter socket and outside
Why would you need a pole? Why not a meter socket and mast on the shed?

Poles are normally only use for distribution to multiple buildings, or temporary services, or temporary structures such as mobile homes.
 
  #14  
Old 04-06-15, 04:29 PM
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I would need a pole because my building is not attached to the ground. It is a prebuilt 12'x20' bulding. I would love to just run like a 30 amp breaker off of my main 200 amp breaker box in my house. I thought I would only need 10 gauge wire for this but from what people here are saying I would need 8 gauge. One hundred and twenty-five feet of 8-3 UF is almost 400 bucks. Then I would have to rent a trencher and dig a twenty-four inch trench 100' to my building. So from what I understand I am looking at 600 bucks easy to run it off my existing service.
 
  #15  
Old 04-06-15, 05:19 PM
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Running type THHN/THWN through conduit would be less than $300 for the wire and less than $30 for the conduit so right there you have saved about $100 dollars AND made the job a bit easier. IF your local inspector will allow you to re-identify smaller than #4 conductors (some will, some won't) you can buy a 500 foot spool for about half the cost of the individual wire, about $135 in my area. Is your soil so hard that you need a trencher?

Further, you have not done a demand load calculation so you don't even know if you need #8, #10 or #6 conductors.

Does that $13 a month include any electricity or is the power in addition to the base charge? $13 a month is $156 a year or $780 for five years and if it does not include some amount of power it makes the cost of installing your own wiring start to look pretty darn good, assuming that you won't be moving in a year or two.
 
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Old 04-06-15, 05:21 PM
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I thought I would only need 10 gauge wire for this
That would be correct for 30 amps but with the welder you probably need more than that. Your estimate is probably correct but check the price of mobile home (URD) aluminum quadplex. Example: Southwire 2-2-4-6 Aluminum MHF Wire (By-the-Foot)-30163099 - The Home Depot
 
  #17  
Old 04-06-15, 05:39 PM
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I don't plan to run a welder just a 220v air compressor. About 5 60 watt lights and occasionally a 110 bench grinder, drills, and angle grinders. It is just going to be a little workshop for me to work on motorcycles and such. I think 30 amps would be plenty for me. I am thinking of hanging 10/3 uf the wire specs says it is UV and water resistant.
 
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Old 04-06-15, 06:35 PM
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That would work if the compressor is less then 20 amps and you don't use much while it is running.
 
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Old 04-07-15, 08:38 AM
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I just checked my compressor it is 14 amp. I think I will be fine with a 30 amp service. If I go the route of hanging the wire. Is there special hanger you can buy to hang the wire from. Also I am still stumped as to what to put in the shed as far as a sub panel? Can I use a small 100 amp breaker box or is there something better for my setup?
 
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Old 04-07-15, 09:50 AM
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Can I use a small 100 amp breaker box or is there something better for my setup?
Yes. Use a main breaker 100 amp panel. It doesn't mater that the main breaker is 100 amp. The main breaker serves only as the code required disconnect. The label on the inside of the panel should list the minimum size wire for the main breaker. If it is greater than #10 add pigtails at least as large as the minimum to the incoming #10.
Is there special hanger you can buy to hang the wire from.
No. Some loosely wrap the UF around the messenger (similar to how triplex wires are wrapped around the messenger) or you can just use wire ties.

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Last edited by ray2047; 04-07-15 at 06:07 PM.
  #21  
Old 04-07-15, 11:02 AM
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Ok, thanks for the information. I have an old porcelain "lug" on my house about 18' up where they had the old service wires going before my house was rewired. Could I run a cable like this Shop Campbell Commercial 50-ft Weldless Metal Steel Cable at Lowes.com from the lug to the top of my building which is 15 foot high. Then just use wire ties to fasten the wire to the cable. Also will I need a ground rod for the breaker box in the shed or will the copper ground wire running from my house service box be good. Thanks.
 
  #22  
Old 04-07-15, 02:17 PM
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Most "wire ties", even the black UV resistant, will degrade from the ultraviolet light from the sun. The black ones may last a year or two, the white ones probably not through the summer. They do make stainless steel wire ties.
 
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Old 04-07-15, 06:16 PM
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I'd suggest vinyl coated 1/8" cable. The vinyl reduces abrasion.
 
  #24  
Old 04-10-15, 05:17 PM
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What do you guys think of this wire in the picture? Run this wire off of a 30 amp breaker.
 
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Old 04-10-15, 06:20 PM
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That is not cable it is cord. It would be a code violation to use it. You need UF-b. Examples:
http://www.lowes.com/pd_12853-295-13...r|1&facetInfo=

http://www.amazon.com/Romex-Building.../dp/B000KKK0QY
 
  #26  
Old 04-10-15, 06:39 PM
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Oh ok haha good thing I didn't buy that I am going to goto our local electrical shop in the morning and see what they have. Do you think I would be ok with like a 6 gauge aluminum wire? I know it is a ton cheaper.
 
  #27  
Old 04-10-15, 08:25 PM
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You might be able to find #6 aluminum quadplex (AKA quadruplex or 4- conductor service drop) for overhead use. That would include a bare messenger wire and three insulated wires. The bare messenger is used as the EGC (ground). URD cable (used for direct burial) looks like quadplex but I doubt it is approved for areal use so don't confuse the two. Note also triplex is more common than quadplex but you can't use that because it is only three wires. If you find the quadplex it will be rated for 3 phase service but it will also work as single phase feed.

Note the cord you linked to would not work even if permuted. It has only three wires not four. With cord the wire count in the description includes all wires. With cable the ground is not included so cord would have to be 10-4 if used for 120/240.
 
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