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Thread: Size of service entrance cable?

  1. #1
    DIY Senior Member rdtompki's Avatar
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    Default Size of service entrance cable?

    Is there a standard gauge for residential (overhead) service entrance cable? Seems like the gauge would have to be the same as the utilities overhead wire. I'm going to call my utility tomorrow to verify.

    I don't know that it matters, but my breaker panel which is integral with the meter is 100 amps.

    Rick

  2. #2

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    If you are referring to the aerial wire that's between the pole and service entrance mast (commonly called "triplex"), power companies have their own rules to determine the size.
    Just my 2 worth.

  3. #3
    DIY Senior Member rdtompki's Avatar
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    PG&E refers to this wiring as the "service entrance wiring" which extends from the connection with their overhead wiring to the meter. Looks like the gauge is a local jurisdiction or NEC issue. I'll look at the NEC tonight and call the inspector tomorrow to verify.

    Seems a bit strange that PG&E says "Weatherproof wire is not permitted in conduit" when this same wire is exposed from where it exits the service head to the connection with the utilites wire.

    Rick

  4. #4

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    I always wondered why they don't extend the triplex down the riser and land it at the meter lugs.


    Here we must provide 2/0 copper (200 amp service) for them to attach their 1/0 aluminum. Maybe it gives the electrons an extra boost the last few feet???

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    Licensed Electrical Contractor Speedy Petey's Avatar
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    Quote Originally Posted by Alectrician View Post
    Here we must provide 2/0 copper (200 amp service) for them to attach their 1/0 aluminum. Maybe it gives the electrons an extra boost the last few feet???
    Or that one part is in free air and the other is in conduit.

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    In the Trades Bob NH's Avatar
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    POCO cable is completely the power company jurisdiction and is not based on the NECode.

    From power company jurisdiction (often the short length exposed at the weather head) to the lighting and appliance branch circuit panelboards in a dwelling the conductor size is controlled by Table 310.15(B)(6). From that panelboard to any subsequent circuits including subpanels the conductor size is controlled by Table 310.16 and subsequent.

    Table 310.15(B)(6) allows smaller conductors than Table 310.16. For example; 2/0 copper may be used for 200 Amp service conductors per Table 310.15(B)(6) but only to 175 Amps per Table 310.16.

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    Plumber Cass's Avatar
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    Years back we used to use URD between the meter socket and out the weather head. But they stopped the practice when they realized the insulation wasn't UV resistant.

    It was faster and easier than service entrance cable.

  8. #8
    DIY Senior Member rdtompki's Avatar
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    Thanks, guys.

    I'm going to check the rating on my panel. It's got a 100 amp main installed, but if the panel is rated for 200 amp I may install service cable appropriate to that amperage (I understand the allowable 1 gauge de-rating) in case I ever want to upgrade the service. Would be a bit easier than going through PG&E again.

    PG&E was actually very helpful. The guy I spoke with advised using Sch80 conduit, for example, as being easier than having to put a PVC cover on metal conduit (required in our jurisdiction). All my concern about using the exsting wiring was moot since I was going to have to upgrade from the weatherhead on down.

    Rick

  9. #9

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    You will also need to make sure the wire size is capable of handling 200amps, as well as the meter socket.

    It would not make sense to install 2" conduit/weatherhead/hub, a 200a meter socket and 2/0 wire only to put in a 100a panel. My guess is you will need an entire service change.
    Just my 2 worth.

  10. #10

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    Residential sizes: #4 copper ( or #2 Alum.) for 100 amp, 2/0 copper (or 4/0 Alum.)for 200 amp. But some AHJs have outlawed Aluminum or want one size larger wire, so check with the local insp first.

  11. #11
    Electrical Contractor/Instructor jwelectric's Avatar
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    Quote Originally Posted by ked View Post
    But some AHJs have outlawed Aluminum or want one size larger wire, so check with the local insp first.
    Where? .

  12. #12
    DIY Senior Member rdtompki's Avatar
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    I haven't installed the panel yet. I'm thinking that the cost of a 200 amp panel and 15' of appropriate-gauge service cable is small provided the cable that PG&E brings to my pole is adequate gauge. Might as well go with the 200 amp. I'll verify the required gauge with my inspector.

    Rick

  13. #13
    In the Trades Bob NH's Avatar
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    HD sell a 3-wire 4/0 aluminum cable that is suitable for 200 Amp service entrance. It is a lot larger than the #2 aluminum that the POCO conntected to it when I installed it. You can put that 4/0 into a 2" conduit.

    If aluminum is satisfactory for the POCO then it certainly should be OK for your inside work. They didn't use any antioxodant compound when it was installed and the connections are not covered with waterproof insulation.

    A 200 Amp Load Center and a 200 Amp meter socket may have maximum size of 4/0 so you wouldn't be able to go larger.

  14. #14

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    A few years ago Petaluma city outlawed installation all Alum wire, residential and industrial, but it is approved now. I think it was Newport Beach that wanted me to use #2 Cu instead of the NEC #4...many years ago. The point is check it out- whether upgraded or downgraded-local rules rule! I know the Code says you can only upgrade...but ...it is being done.

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