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Thread: Service Entrance conductors

  1. #1
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    Service Entrance conductors

    Where does it say in the code that when service conductors enter the building that needs to be encased in concrete if it was more than 10' run before it lands on the first disconnecting means? if those conduits were run inside a chase (the switchgear is on the second floor), do they need to be encased in concrete? Thank you

  2. #2
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    Re: Service Entrance conductors

    230.6 Conductors Considered Outside the Building.
    Conductors shall be considered outside of a building or other structure under any of the following conditions:
    (1) Where installed under not less than 50 mm (2 in.) of concrete beneath a building or other structure
    (2) Where installed within a building or other structure in a raceway that is encased in concrete or brick not less than 50 mm (2 in.) thick
    (3) Where installed in any vault that meets the construction requirements of Article 450, Part III
    (4) Where installed in conduit and under not less than 450 mm (18 in.) of earth beneath a building or other structure
    Mike Whitt
    God answers Knee-Mail.

  3. #3
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    Re: Service Entrance conductors

    230.70 (A) (1):The service disconnecting means shall be installed in a readily accessible location either outside of a building or structure or inside nearest the point of entrance of the service conductors.

    The code does not address any length for the "nearest the point of entrance" so each AHJ can interpret this different.

    230.6: Conductors shall be considered outside of a building or other structure under any of the following conditions

    (2) Where installed within a building or other structure in a raceway that is encased in concrete or brick not less than 2 inches thick.

    Chris

  4. #4
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    Re: Service Entrance conductors

    Wow jwelectric I was slow in typing good post.

    Chris

  5. #5
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    Re: Service Entrance conductors

    Thank you all for replying. Just wasn't sure where that 10' rule came from. Somehow, I thought the 10' tap rule have something to do with it.

  6. #6
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    Re: Service Entrance conductors

    Originally posted by raider1:
    Wow jwelectric I was slow in typing good post.

    Chris
    I didn't type. The joys of the NEC on CD, just copy and paste.
    Mike Whitt
    God answers Knee-Mail.

  7. #7
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    Re: Service Entrance conductors

    In Washington State, the disconnecting means has to be within 15 feet of where the conductors enter the building. The existence of that WAC rule confirms (to my mind, at least) the absence of a similar distance requirement within the NEC itself. Of course, if you do keep the conductors below 2 inches of concrete (as Mike pointed out), you can run them to the other side of the building. I have used that design. The conductors don't "enter" the building until they come up from beneath the concrete barrier.
    Charles E. Beck, P.E., Seattle
    Comments based on 2014 NEC unless otherwise noted.

  8. #8
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    Re: Service Entrance conductors

    Hello, I'm new to this forum. This is my first post! This discussion caught my attention. Just wanted to add my 2 cents.

    1) 230.6 Conductors Considered Outside the Building

    If the installation meets the requirements of 230.6 the conductors are not considered to be inside the building.

    2)This is copied from the 2002 NEC Handbook.

    VI. Service Equipment — Disconnecting Means
    230.70

    [QUOTE] No maximum distance is specified from the point of entrance of service conductors to a readily accessible location for the installation of a service disconnecting means.....
    ....Some local jurisdictions have ordinances that allow service-entrance conductors to run within the building up to a specified length to terminate at the disconnecting means.....

    (1) Readily Accessible Location. The service disconnecting means shall be installed at a readily accessible location either outside of a building or structure or inside nearest the point of entrance of the service conductors.

    I read a SE/USE cable manufacturer's product spec literature and found that they say it's not intended for use in interior building wiring. It doesn't carry the insulation flame retardant rating that's required for interior use. It also gave a maximum length that's permitted to be run inside to the service disconnect. So, in order to maintain their UL listing, the installation of this cable must meet their requirements.

    In other words, the maximum distance SE/USE cable can be run in the interior isn't set by the NEC. It's set according to what the cable manufacturer has to do to meet UL standards.

    Local standards just make it easier to comply, by clarifying what the maximum is. It's 5 feet where I live.

    Cheers,
    EG

  9. #9
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    Re: Service Entrance conductors

    Hi EG, welcome to the forum.

    It is true that 'USE' is not for interior use.

    SE or the other hand is flame retardant and can be used inside.

    [ September 29, 2005, 05:35 AM: Message edited by: iwire ]

  10. #10
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    Re: Service Entrance conductors

    Originally posted by EnerGreen: In other words, the maximum distance SE/USE cable can be run in the interior isn't set by the NEC. It's set according to what the cable manufacturer has to do to meet UL standards.
    True. But if you have it under concrete, it's not "interior" until it leaves the concrete. I think that the reason Washington has a 15 foot requirement is to limit the risk of accidental damage to the conductors. A long cable, even if in conduit, is more likely (than a short cable) to get bumped by a forklift (or some other WMD).
    Charles E. Beck, P.E., Seattle
    Comments based on 2014 NEC unless otherwise noted.

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