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  • Gauge of wire for power

    I need to run a 220 single phaze line from my breaker box about 150 feet, what gauge of wire should I use to do this?

    I have been told to use 4 gauge, and that stuff is pricey, but I like doing things right, any suggestions???


    Jerry

  • #2
    Wire size depends more on the current than the voltage. Voltage, among other things, determines the insulation requirements. In general you want only a 5% voltage drop at the rated current.

    I can check the NEC book if you tell me the current it will be carrying. In any case, I would not use anything less than #12. Oh, and is this indoor or outdoor?

    Paul A.
    Paul A.

    Make it fit.
    You can't win and there is a penalty for trying!

    Comment


    • #3
      What are you wanting to power up with it?

      I have #6 going to my shop.. taking 50 amps down there. It is too small already.

      David

      From memory, 14 ga = 15 amps, 12 = 20 amps
      10=30 amps 8 = 45 amps 6 =50, 4=85 2 = 100..
      2/0=200 They (nec) changed all the ampacitys in the last ten years, but I still use the old school numbers. Check the neca code book to make sure.. my memory is getting worse.

      Take more then you need, you;ll apperciate it later. I am already overamped. Not clicked the breaker lately but the big lathe and lights comes out close. (lathe= 37amps) When I am running that old 24inch lathe it rumbles the building..

      David

      [This message has been edited by ibewgypsie (edited 06-01-2004).]

      Comment


      • #4
        It didn't make sense to pull 100 amps out of my house that only had 150 amp supplyand run it 40' to the garage. So I went thru the hassle of having a separate meter put on my garage. Lots more trouble and money, but I am glad i did it. Now I have 200 amps in the garage.
        david from jax
        A serious accident is one that money can't fix.

        Comment


        • #5
          Minimum wire size is based on the overcurrent protection. Then you can upsize it as far as you want for lower drop, assuming the wire clamps on the breaker are rated for the size.

          So what size breaker is feeding this wire? That will immediately lead you to the sizing.

          1601

          Keep eye on ball.
          Hashim Khan

          Comment


          • #6
            The city won't let me put in a separate meter, their request for a vairance is a joke, $1,300 for the application and $2,000 for the actual permit, if it is granted. The electric company will increase my service without a problem.

            I want to put 100 amp service to my garage and the way the house and the garage set, I will have to trench a path from the back of the house around to the garage. No clear path thru the house with out major structural changes.

            Right now I am think 4 gauge copper.

            Jerry

            Comment


            • #7
              I can answer your question but first you need to give more information. I have been a journeyman lineman for over 20 years. What is the amperage of the panel you are pulling power from? How much capacity are you using out of your excisting panel? Do you live in a mild climate small house. Or large house extreme climate? Do you use electric only or do you have gas? These questions will help me determine how much more capacity you excisting panel has. You may need to upgrade your excisting panel. Do you have any breaker space left to pull a service from that panel? If the answer is yes I have room and I am not using all the capacity out of my excisting panel. I would run 1/0 aluminum 4 wire service to a sub panel with a 100 amp breaker, ran in 2" conduit if you don't need to put too many 90* bends, if you have more than 3 90* bends run 2,5" or 3" conduit no thin wall schedule 40. A 100 amps service ran 150' under ground would require a #2 copper service. You can run #4 if it is ran overhead due to the air cooling the wire. You must go to a larger size when in conduit or direct burried. Personally I would not direct bury anything unless it is temporary, if it ever goes bad you get to dig a new hole and start over. If you have any more questions e-mail me or post it.
              Mike

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              • #8
                I live in 3,200 sq ft house. With 200 amp service, because it is an all electric home.The climate is temperate, and really not too bad. I am currently planning on taping at the junction going into the panel and then setting up a seperate 100 amp box in the garage.


                Hope this helps,

                Jerry

                Comment


                • #9
                  That is not legal NEC and your local building department will not allow you to connect on your service connection. And if you connect on the low side of the breaker you would have to run 4/0 al or 2/0 CU. The wire has to be able to carry the load the breaker is rated for other wise the wire will burn in two before the breaker kicks. You could tap in with a short piece of wire to a sub panel near your service panel but it still needs to be capable of handling the load the main breaker is rated for. The best bet is if you run a separate breaker out of your box. I assumed you were wanting 100 amps is that correct?
                  Remeber the breaker is there to protect the wire. If you don't have any breaker space you may be able to instal some slim line breakers and gain enough space for a breaker to run your shop. If you contact your power company they can use your average consumption and give you an idea of how much demand you are putting on your excisting equipment. If you down size these wire sizes I have mentioned for your service drop running 150' you will have problems with voltage drop. The right way to do this is to install a breaker in your excisting panel run your service from that breaker to a sub panel in the shop. You can wire your shop from that panel. Remember you must run a 4 wire service 2 hot legs a neutral and a seperate ground wire that will be code. I hope this all makes sense.
                  Mike

                  [This message has been edited by gundog (edited 06-02-2004).]

                  Comment


                  • #10
                    The size of your service wire depends on a couple of things with distance and amperage draw and conductor material, copper or aluminium, being the main ones. Acceptable voltage drop is another and depending on where you are, there will be legal requirements for what`s allowed that almost certainly vary between jurisdictions, regardless of what you would prefer to use. Permits need to be taken out I expect and that means an Electrical Inspector will probably check it out. Screw up and he will make you correct it, with all that that entails. You really need to talk to a qualified local electrician who will be the best person to answer your question.
                    Location: Saskatoon, Saskatchewan, Canada

                    Comment


                    • #11
                      Do not run anything outside the panel without breaker or fuse protection.

                      HV transformer Pole breakers supplied by the electrical company are oversized so far your house would burn down probably before they kicked.

                      You need a breaker and at least #2 wire. YOu need two hot legs, A neutral (some code areas allow half sizing) and a ground (it can sometimes be downsized too). INside your panel you might find you only have a neutral-ground common.. but you need to run the ground anyways. It is a saftey wire. It never made sense to me to carry 4 wires to a 3 wire system but it does help save people.

                      If you bury it in the ground in conduit, make sure it is at least 18" deep. Make sure no water can get into the system.

                      Next option, direct burial cable (usually grey). You can purchase it at home depot.

                      Please don't go under these guidelines. At least do this much. Place a 100 amp breaker in the house to protect the wire-service and a sub panel in the shop with breakers to protect the loads. GFI's in wet locations (I have on the front of my buildings for battery charger)

                      Some counties will not allow feeding of external buildings off a home. That kinda sucks but it stops people from getting into dangerous predictaments.

                      I am a licensed electrican (I survived a apprenticeship without burning anything up and passed a 6 hour exam), IN Chattanooga Tn. I mostly do controls-instrumentation type work (lil bitty wires).

                      David

                      Comment


                      • #12
                        I have a 200 amp service on a pole in my yard that I ran 4/0 Al. to the shop with a 200 amp panel, the I took a 100 amp breaker and powered the house from that out of the shop. I have good power in the shop and the house is not lacking anything either. We have nat. gas for heating.

                        Comment


                        • #13
                          I have set up 200amp to my studio and I am setting up a seperate 200amp service underground to the house.The underground is because of trees,fallen branches!I think if you check with any electrican,who might also be a metal or woodworker, the more amp you have the better.Get at least a 40 space box,you will fill it up and it gives you versatility.In the long run,putting in a bigger service at the start,will save you money.The seperate meter which always is a problem,My town charges commerical rate,on more than one meter.Solution start a small business,make some money on your interests, then use the charges as a write off!The U.S. government wants you to make some money anduse your skills.

                          Comment


                          • #14
                            Currently, I have a seperate wire to the furnace breaker box and then another breaker box to the rest of the house. The power has been split at this point. I can set a breaker box for the run to the garage at the main point and then a sub box in the shop.

                            Jerry

                            Comment


                            • #15
                              Hi Jerry,
                              I am not sure of the code in your area in most of the places where I have worked you can run a breaker box within 10' of the service entrance. Some houses do not have a main breaker at the service entrance they just have a meter socket and then the main breaker must be within 10'. You should not tap off the high side of your breaker and run to your garage. If you can send me some pictures of this instalation I will be able to help you better. Another thought you might be able to access your garage by routing the wire through your attic, or maybe under your house if you have a raised foundation. Is the garage attatched to the house?

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