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  • Electrical Feed?

    I am having some problems with the electrical feed to my New Shop. I spent so much money and wasnt home much to oversee the construction and so on. I asked the Electrician (Rob) to install 100 amp sceptre pipe and wire for my ditch i had dug from the house to the shop, Later (some nights im home eleven or later fromwork) I look at the sceptre pipe and it looks small ?? One inch inside diameter, now im no electrical genius ,I leave my questions to Dave Coffer regarding that stuff) But i didnt think seperate wires could be run through a one inch pipe to supply my 100 amp feed that i wanted.Well can it be done> It (the ditch) is backfilled and im so pissed of with my 60 amp service going into my garage im gonna blow a vein in my large Head. LOL. Anyhow can i run seoperate wirers through this One Inch sceptre Pipe (Inside dimension is One Inch) to get my 100 amp service in my new dream shop? Thanx Mike (currently a really Mad Man)

  • #2
    Table 901.10.3.1 Maximum* No. Cables Available in Cable-Conduit


    http://epg.modot.mo.gov/index.php?ti...ation_of_Plans First link that popped up..

    #2 used to be the smallest used for 100 amps.. I don't have a codebook handy.. it'd be a American code book anyways.
    This table here on this page says you can put two #2's in a 1" pipe.. Copper.. Where is the neutral, and ground going coming from the panel feeding this service? no room..

    http://www.elliottelectric.com/Refer...ill_Table.aspx This table says you can put 3 #2's in a one inch using THHN copper.. now, that'd do the neutral, if you can use the metal conduit for a ground in your locale?
    Last edited by Dawai; 11-07-2008, 12:21 PM.
    Excuse me, I farted.

    Comment


    • #3
      I used 2" pvc conduit for both my service panel and also to the shop subpanel. Can't remember the wire gage but it was some honkin stuff. The pvc is not a big ticket item so why scrimp on the size ?

      Comment


      • #4
        Originally posted by David E Cofer
        http://www.elliottelectric.com/Refer...ill_Table.aspx This table says you can put 3 #2's in a one inch using THHN copper.. now, that'd do the neutral, if you can use the metal conduit for a ground in your locale?
        Better off driving a ground rod at the new panel being it is a seperate building and being underground conduit, I'm sure it is PVC

        Comment


        • #5
          Originally posted by JoeFin
          Better off driving a ground rod at the new panel being it is a seperate building and being underground conduit, I'm sure it is PVC
          The US NEC as interpreted in my area requires that a "subpanel" have the ground brought as a separate conductor to the main panel.
          No local ground rod is allowed.

          Comment


          • #6
            Originally posted by fasto
            The US NEC as interpreted in my area requires that a "subpanel" have the ground brought as a separate conductor to the main panel.
            No local ground rod is allowed.
            Same here.

            Comment


            • #7
              There again.. his area of the world may still have a three wire service.. (two hots and a neutral-ground wire)

              I still look around when I see the "green" bond screw in a panel and neutrals and grounds on the same bus bar..

              That'd do it too Mike.. Is Audrey better?
              Excuse me, I farted.

              Comment


              • #8
                Anyone who maxes out on the wire size for conduit is asking for the pull from hell........ especially on a long run, and double especially if there are a max number of bends. If you leave ample room, it gets a LOT easier, it can be upgraded later, and it really doesn't cost much extra compared to digging etc.
                1601

                Keep eye on ball.
                Hashim Khan

                Comment


                • #9
                  Correction

                  I didnt buy the Sceptre plastic Pipe for the underground feed my stupid electrician did. I was out every day working for a iving. Im still so pissed of at him. hes lucky he hasnt been around lately. I was told that 3 number 3 wires and a ground will fit if you carefully stuff them evenly in any ideas again Thanx Guys Im quite pissed off.

                  Comment


                  • #10
                    Well 3 #3 THWN seems to be OK, and that in 75deg C IS in fact 100A.......

                    It's the minimum, minimum possible, but it IS 100A.

                    Now the ground wire has to fit in there too, if this is a split 240V feed.
                    1601

                    Keep eye on ball.
                    Hashim Khan

                    Comment


                    • #11
                      my stupid electrician did
                      For youse who don't know Madman, he has these long lanky arms you'd hate to box with.. He could hit you where you couldn't touch him..

                      Be nice to the "Stupid" electrician Mike, he might have child support and have a reason he used the one inch.. *like he stole it and sold it to you? (not that I'd stir the pot or anything, it might be a UNION brother up there..) Them Canuck electricians can work in the USA, but we can't work up there.. unless we prove our INDIAN blood, they have a cross the border agreement for feather heads.
                      Excuse me, I farted.

                      Comment


                      • #12
                        Mike, check a curent code book. I only have an old one so things may have changed, but if you run two # 2 conductors your ground only has to be a # 6 in copper and can be bare. Also the netural can be a # 6.
                        So two #2's a bare #6 and an insulated #6 should go in a 1''trade size conduit without exceeding the maximum fill percentage.

                        Steve

                        Comment


                        • #13
                          Hi Mike,

                          All of the above is great info and correct. I just did the calcs on your 100 amp feed and the answer is 3 #3 and a #6 ground will fit in a 1 inch EMT conduit. Your conduit, I think, is plastic but you said it is 1 inch ID so it would basically be the same. The above wire specs would be the minimum I would use for a sub feed. You could down size the neutral as mentioned above, but I would not unless you just cannot get the wires through. With all of the new switching power supply type equipment (computers, TV's, VFD's etc.), we are seeing an enormous number of neutral failures in older homes and offices. This is caused by harmonic currents on the neutral from the switching supply. This might not be a problem for you but why take the risk. How long is the run and how many bends are in it (# of 90's, 45's etc). If it is a fairly short straight pull you won't have a problem, if longer and more bends use a LOT of pulling lube or you will hate yourself. I realize that the ditch is already backfilled but now would be the time to dig and install larger conduit. If you decide to go that way leave the 1 inch in place for future stuff (phone, cable TV, computer network cables etc).

                          If it were me I would have a SERIOUS talk with the electrician boob and make him explain himself and fix the problem at his cost. You clearly told him what you wanted so it was his responsibility to do it right and find out what is right if he didn't know. When I am hired to do a job I am expected to do it right and to code if required. If I don't know how to do something I tell the customer up front and if they are willing, I will find out how to do it and quote a price, if they are not or I find out I really can't then I respectfully pass on the work. A mad customer is worse by far than no customer .

                          Keep us posted, please.

                          Robin
                          Robin

                          Happily working on my second million Gave up on the first

                          Comment


                          • #14
                            Originally posted by fasto
                            The US NEC as interpreted in my area requires that a "subpanel" have the ground brought as a separate conductor to the main panel.
                            No local ground rod is allowed.
                            You would be WRONG - Check your NEC before inserting foot.

                            As long as the Main Service is less then 1000 amps and 600 volts and the building (garage) is "Detached"

                            It will be in the Italic print foot notes if your using the soft bound version of the NEC or Brown Italic Print foot notes on the hard bound version of the NEC.

                            And just for Clarity the 'N' in "NEC" stands for "National". So when you say "in my area" you completely lose me on that one. I've been in almost every state of the union engineering and supervising the installation of Electrical Control Systems and the first thing I ask the local code authority is "Do you supersede the NEC". because in some places they can and do. Like Florida and Minnesota for a very long time would not allow Romex. California was the only place I was caught and it was a stupid side job at that.

                            Originally posted by doctor demo
                            Mike, check a curent code book. I only have an old one so things may have changed, but if you run two # 2 conductors your ground only has to be a # 6 in copper and can be bare. Also the netural can be a # 6.
                            So two #2's a bare #6 and an insulated #6 should go in a 1''trade size conduit without exceeding the maximum fill percentage.

                            Steve
                            Steve

                            He might also have a problem with that statement as well

                            He does need to run a “Neutral Conductor” and given the application of the panel, (panel service / rec. loads) de-rating of the neutral conductor is not allowed. In addition, given the likelihood of the addition of “Veriable Frequency Drives – VFD/VSD” and the ensuing Harmonic Distortion caused by such devices, derating of the Neutral Conductor is NOT Allowed. (see NEC section 220 – 10(b) and 10(c) )

                            The Good News is his local electrician was correct and You Can run 3 #2awg conductors in 1" PVC and re-establish ground (ground rod / water bond) at the panel.

                            Does Mike have a reason to be pissed - Sure he does.

                            Given the cost difference between 1" pvc and 1 1/2" or 2" pvc, who in their right mind runs 100% fill. The guy is probably NEW or "Side-Jobbing" to feed his family and is keeping it "Tight and By the Book". His skills as a contractor can certainly use improvement as he could have listed "Up-grades" (such as 2" PVC feeder conduit") and their subsequent cost in the contract
                            Last edited by JoeFin; 11-08-2008, 08:20 AM.

                            Comment


                            • #15
                              The guy is probably NEW or "Side-Jobbing"
                              And picked it up off a job.. for nothing.. which is what I'd pay him.
                              Excuse me, I farted.

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