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Lost in the Mire

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  • Lost in the Mire

    Life Was supposed to be easier than this. The plan was to wire a storage building myself and then get a contractor to run the service from the house. We passed the rough in inspection and called three different contractors. Since no one has called us back so I guess I'll have to get the power to the builing from the house myself.

    The building is a 150 foot run behind the house. I am guessing with waste and bury depth and so on the total run will be 175 feet or so. We have a 100 amp panel installed. This is a new house with a 200 amp service. There is a 200 amp forty space panel inside. The meter base is a combination box with a 200 amp breaker that will kill the entire inside panel and has pass through lugs. The box has eight spaces. Currently there are three 2 pole 220 volt breakers installed with one 15 amp single pole breaker.

    Ideally I'd come out of that box and go underground to the building. The plan was to move the 15 amp single pole breaker to the panel inside the house and install a 100 amp 2 pole breaker in the outside box.

    I have tried to do my homework but there is lots of conflicting info on wire size being posted all over the web.I have read posts that seem to say everything from #8 to 4/0.

    I am planning on using 4 conductor wire 2 hot 1 neutral 1 groundI am under the impression I need at least #1 al or #2 cu because of voltage drop and that it has to be buried at least 24 inches and where it is under the drive it must be in schedule 40 conduit.

    1. Can I count two pole breakers as one breaker to stay under the limit of 6 or do I have to install an extra box on the back of the house to feed the building?

    2. What size wire do I need to run?

    3. What designation do I need? I'd prefer direct burry cable- I assume SER and SEU are overhead only. I know I can use the UFB if I can get the wire size down to something less than trans Atlantic size.

    4. I assume I can wire it just like any other breaker. Hot and Hot to the Breaker, white to neutral, ground to the bar.... then on the storage building, hot and hot to the lugs, white to neutral, and the ground to the bar that is also wired to the new ground rod at the building.

    5. Is there anything else I need to know or ask?????

    Sorry for the length. Wanted to be complete! Any all all input is greatly appreciated. Thanks in advance!

  • #2
    Re: Lost in the Mire

    1. I'm not sure what you mean by the limit of 6. Currently a 2 pole breaker counts as one breaker. When 2008 code comes into effect 2 pole breakers will count as 2 breakers in regards to panel limitations.

    2. you are correct #2 copper or #1 al

    3. I'd run a conduit the whole way and use THHN but there are other ways of doing things.

    4. correct just do not bond the neutral in the new panel.

    Bury caution tape between the electrical and surface.


    • #3
      Re: Lost in the Mire

      The single breaker (200 amp) that is a main shut off, (service disconnect), counts as one, the following breakers do not count in the 6 shut off rule, If there was not a main shut off and there were six indivigal disconnects that had to be pulled to shut down the power then that rule come into play, or that is my understanding of it.

      Key word: Service Disconnects

      230.71 Number of Disconnects
      (A) Maximum. There must be no more than six service disconnects
      for each service permitted by 230.2, or each set of service-entrance conductors permitted by 230.40, Exceptions 1, 3, 4, or 5.
      The service disconnecting means can consist of up to six switches or six circuit breakers mounted in a single enclosure, in a group of separate enclosures, or in or on a switchboard.

      The rule is six disconnecting means for each service,
      not six service disconnecting means per building. If the building has two services, then there can be a total of twelve service disconnects (six disconnects per service).
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      • #4
        Re: Lost in the Mire

        Ok, what you want to do is run a 100 amp service to a separate building on the same property. Normally #4 copper to service 100 amps is OK, but with the distance of 175 feet I would move up to #2 copper. I would bury schedule 40 PVC electric pipe and pull 3 #2 THHN wires in it to the panel in the storage building. There you would bond the nuetral to the can using the bonding screw and run a separate ground rod. You do not have to run a ground from the house to the storage building, only 2 hots and a nuetral. Your ground will be re-established at the storgae building with a separate ground rod there. This is not considered a sub panel.


        • #5
          Re: Lost in the Mire

          Yep, what Oroking side,

          I would not even think of pulling a ground from the house. Buy a ground rod and a clamp and how ever much wire it takes to go from the panel to the rod and youre set. A lot cheaper.



          • #6
            Re: Lost in the Mire

            Thanks to all for the info provided. It has been a big help. I appreciate ya'll sharing your knowledge. If any body thinks there is something else I should know...I hope you'll add it.

            While I've been reading your posts, I kept doing research. I found some additional info on one issue we were discussing.

            "NEC 250.32.A and B dictates how you must design your grounding whether it be a three wire feeder [two hot conductors and a neutral only with no equipment grounding conductor ran with that feeder] feeding a building that has no non-current carrying metallic path such as a metal water line of a grounding conductor of a phone line etc. or whether it is required to have a four feeder [two hot conductors a neutral and an equipment grounding conductor ran with that feeder as required to serve an accessory building that does have a non-current carrying metallic path such as a metal water pipe or grounding conductor of a phone line etc."



            • #7
              Re: Lost in the Mire

              There is a pretty good book you might want to buy to help keep you out of trouble when you're doing this project. It's based on the NEC with some local code caveats. Title is "Wiring Simplified, 41st Edition." by H.P. Richter, W.C. Schwan and F.P. Hartwell. It will answer a lot of your present and future questions, and do keep on asking people here for help, they're very knowledgeable. You can usually pick one up at a decent sized bookstore, (Even Fleet Farm carries it here), or through Lindsey Publications which will ship it to your home in less than a week. It's about $13 and worth every penny as a reference work for your library and future projects. Good Luck.
              Jim Don