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Electrical splicer reducer

drh | Posted in General Discussion on December 9, 2007 07:39am

Hi all,

Is it permissible to use a splicer reducer to increase the size of a wire coming off of a breaker?

I have 100 amp service to my house. There is a main disconnect (100 amp breaker) outside below the meter and a load center inside the house with the branch circuit breakers. This panel is about 40 feet away from the disconnect and is fed by an old 3-conductor (2 insulated, 1 bare) #3 AL wire. Not only is this wire not properly sized for this load, but it is also means there is no isolated ground between the main disconnect and this subpanel (right, sparkys?)

Eventually, I’ll probably have the whole service upgraded, but for now I would just like to replace this cable with 2/0 SER. I think the largest wire a 100 amp breaker can take is 1/0. Would I be allowed to use a splicer reducer in the main disconnect box outside to step up 1/0 wire coming out of the breaker onto 2/0? Is this a bad idea ?

Thanks.

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Replies

  1. plumbbill | Dec 09, 2007 08:45am | #1

    Yes you can increase the wire size.

    The breaker is designed to be the weak link of the circut.

    What i'm not sure about is the "isolated ground", I do commercial work more often than not all the wires are insulated, but the panel, disconnects & other boxes are grounded, the conduit is grounded. So I have a tough time with the terminolgy of an isolated ground.

    "Why do you hurt me when I do bad things to you?" My youngest son to his older brother

    1. User avater
      BillHartmann | Dec 09, 2007 03:58pm | #3

      "What i'm not sure about is the "isolated ground", I do commercial work more often than not all the wires are insulated, but the panel, disconnects & other boxes are grounded, the conduit is grounded. So I have a tough time with the terminolgy of an isolated ground."Isolated ground is not the correct term, but what is has is not correct undercurrent codes if the disconnect is mounted on the house and not on a separate structure such as a pole.The basic connection is that the neutral is bonded Ground Electrode system (ground rods, etc) at the Service Entrance and from that point equipment grounding conductors, aka The Ground, (which includes metal conduit) are run. At no other point in the system in that STRUCTURE, are the grounds and the neutral allowed to be connected.The service entrance starts at the service drop for overhead service and includes the meter and the main disconnect. Any place along that path (and I think multiple places on that path are allowed) the neutral and ground are bonded.In most houses main disconnect is in the load center.But where it is separate then the load center becomes a sub-panel and the feed needs to be 4 wire. And the load center is setup with an isolated neutral bus..
      .
      A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.

    2. drh | Dec 09, 2007 07:55pm | #5

      Sorry, wrong terminology on my part it looks like. I was referring to the fact that the ground is only supposed to be bonded to the neutral at the service entrance.My original plan to correct this was to run a separate ground wire to the indoor panel and move the few branch circuit grounds (most circuits are run with old 14-2 without ground) off of the neutral bar and onto the ground bar. Then I saw that the neutral conductor feeding the panel was bare, so its hard to keep it from being in contact with the frame of the panel. I also realized that the the whole feeder was undersized for 100 amps so I decided to replace the whole feeder.

  2. User avater
    BillHartmann | Dec 09, 2007 03:50pm | #2

    The SQ D catalog show that the 100 amp panels are limited to #1 wire connection to the main breaker or main lugs, depending on the type of the panel.

    But it also shows that 80-125 amp 2 pole breakers can take upto 2/0 for the load side connections.

    One big problem is finding room for the splices. They will take up lots of room.

    Now you could add an extra box just outside the panel. But that is more cost. And you would need to leave the SE cable extra long to have wire to bring it into the panel when it is upgraded.

    For only 40 ft I think that you best bet would just to replace it with #2 AL and then when you do up grade replace everything at once.

    .
    .
    A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
    1. drh | Dec 09, 2007 07:49pm | #4

      I am also upgrading to a 200 amp panel (although I just checked and the current panel is the 80-125 amp you describe so it would take 2/0).I think the real solution would be to relocate the panel closer to the service entrance, but there is no good location for it. I could also relocate the service entrance but the only other good spot would bring the (overhead) service drop across the middle of the backyard to the center of the house. Besides aesthetics, there are two trees to deal with, etc. I like where it is on a back corner.I say there is no good spot to move the indoor panel to, but I am actually installing the new panel about 3 or 4 feet away from the old, to move it out of a clothes closet (and bring it below 6.5' height, etc. etc.)I've run through a lot of scenarios and this seems to be the best one. I got a good deal on the new panel, and I'll be spending about $150 on 40-50 feet of 2/0 AL SER which will let me go up to 150 amps eventually (a load calculation on my house shows I need 115, so I don't see the need to spend the extra money to go all the way to 200).I've never used the splicer reducers before. Do I just wrap them with tape? Seems like that might raise an inspector's attention.Thanks again for the advice.

      1. User avater
        BillHartmann | Dec 09, 2007 08:33pm | #6

        I did not realize that you where chaning out the panel at this time.Tpically split bolts are used for those kind of splices.And the idea is to build up the insulation over the bolts as thick as the insulation on the wires. And it takes several layers. Start with friction tape. That is less likely to get through. Several layers of that followed by several layers of vinyl.But there are another type of splice. Don't know what they are called. But it is a barrel, some times a square, that is bored through the long axis for the wires and on the side for set screws. Longer, not near as bulky as the split bolts. And some are preinsulated so you don't need anything else. They are pricy and you will need to go to a supply house.But if you have a 100 amp breaker in the disconnect them you can probly hook up directly at that end and with the new panel 150 amp panel it should also take the wire.Unless you are doing this "under cover" you might as well upgrade the whole thing to 150 amps.Most likely you already have a 200 amp meter and box. At least in this area that is standard no matter what the size. So you will need a new disconnect and possible wires in the riser..
        .
        A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.

        1. drh | Dec 09, 2007 08:57pm | #7

          You probably know better than I do, but the device you are describing is what sounds like what I have been calling a "splicer reducer". The ones I have seen aren't insulated but searching for "insulated splicer reducer" on Google is showing me some that are, so I'll probably go with that.The meter is pretty old and probably not rated for 200 amps (house built in 1955). I need to go double check what size the wires are in the riser but they would also need to be replaced too like you suggest. Everything outside needs to be upgraded, but I was going to do that at a later time. The riser pole does not extend above the roof line (the weatherhead sits right below the soffit) and the drop also goes across my driveway, so when I do all of this eventually (which I will pull a permit for), I'll need a new meter base, disconnect, riser pole 12 ft off the ground....The main goal right now is to deal with what I see as possible major safety issues, those being the feeder is undersized and large appliances like my stove and dryer aren't grounded. There is also one room that has older AL wire running to all the receptacles and switches, which are rated only for Cu wire. Again, I've seen split bolts, but never used them -- should I use these instead?Thanks again.

          1. User avater
            BillHartmann | Dec 09, 2007 09:50pm | #9

            No I think that the splice reducers are better. Not as bulky and less like to cut through the tape insulation.I undeerstand what you are talking upgrading in stages.A friend of mine bought a house that was built about the same time.The original wiring seemed to be very high grade for the time. My guess is that it was an 80 amp service and I guess that is what you have.At sometime in the 70's there was a major addition with a sub-panel. Many, many, problems with that 3 wire run, no romex connectors on many of the runs, etc. And at some time the panel had been replaced with a 100 amp.And she wanted to go with electric stove and builtin MV which required upgrading the service.I was busy running new circuits to the kitchen, the master bedroom, another bedroom used for the office. Replacing some lights in the basement/garage that was partial wired with lamp cords and 14-2 with a separate wire for the 3-ways, flying splices, hidden boxes,,and a few other things.So someone else was brought in to do the service change. the meter it'self was a 200 amp. But the drop was a SE cable. And when he move the meter to the side so that he could keep it partial hot while he mounted the new serice the insulation on the old SE cable started cracking and started arcing..
            .
            A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.

      2. woodway | Dec 09, 2007 09:48pm | #8

        If you do decide to move the load center, what or how are you going to route the existing branch circuits to the new load center without having to rewire the whole house or add a new splice box and cables to connect to new panel? I have a similar problem at my house and when it comes time to upgrade to a 200 amp panel I've decided to locate it at the same position as my existing load center. Are you rewiring the house too?

        1. drh | Dec 10, 2007 12:37am | #10

          Yes, I plan on rewiring the whole house eventually.The first breaker I install in the new panel will be a 100 amp breaker. I will feed the old panel off of this, so I can move things over slowly.If you don't plan on rewiring your house I think you could just turn your old panel into a giant junction box and do all your splices there. I think that is allowed. Although, if all your wiring is fine, and the location of your panel is ok I would probably do what you are doing and put the panel in the same spot.My panel is in a location not allowed by code (among other violations :-), and most of my branch circuits are ungrounded. If I looked closer I'd probably find more Al wire on Cu devices, 14 AWG on 20 amp breakers etc.

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