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Thread: Existing Subpanel

  1. #1
    Join Date
    Oct 2018
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    boston, ma
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    Existing Subpanel

    There is an existing sub panel in the attic of a single family dwelling. It was fed with range cable. No alterations have been made. Do I need to install a EGC or is the existing installation ok as it stands?

  2. #2
    Join Date
    Dec 2006
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    Chapel Hill, NC
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    That would be an authority having jurisdiction call. In some areas they allow you to leave it as is and others will not allow you to add a circuit to an existing panel that has a violation.
    They say I shot a man named Gray and took his wife to Italy
    She inherited a million bucks and when she died it came to me
    I can't help it if I'm lucky



  3. #3
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    May 2018
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    Jamaica and london
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    Dennis, by violation, would it be the range cable? I mean, if you needed less than 50 amps, wouldnt that be what you use? Or would it be required to be fed by something else?
    Or, is the fact it is in the attic the problem? Not accessible under new rules? What if it was meant to feed cooling equipment originally, and was put where the equipment was at the time? I am asking because I am trying to learn not just to make more work of this. Remember a home in Va that had a panel in the attic area, and that panel was left there when the cooling was moved to a ground pad ten years later, using one of those newfangled (at the time) out door cooling systems
    Student of electrical codes. Please Take others advice first.

  4. #4
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    I assume the range cable is the old 3 wire cable. You may be able to make it work if the panel doesn't have any 240v circuits by converting it to 120v but then the load may also be an issue.
    They say I shot a man named Gray and took his wife to Italy
    She inherited a million bucks and when she died it came to me
    I can't help it if I'm lucky



  5. #5
    Join Date
    May 2018
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    Jamaica and london
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    Oh.. had not remembered that part of it. Like with the old stoves and the new stove requirement to get neutral wire or GEC to it, depending on design, to make a four wire system. If all the wires are the same size and insulated, and the building was steel construction, could you not supply the GEC by running it to the steel? then make sure the original wire was in the neutral and not ground section at the panel?
    Again, not sure of conversion requirements, compared to simply running new cables, as I mainly use conduit so would simply pull a new neutral in the conduit.
    Student of electrical codes. Please Take others advice first.

  6. #6
    Join Date
    Feb 2003
    Location
    Minnesota
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    6,937
    Quote Originally Posted by Liyus View Post
    There is an existing sub panel in the attic of a single family dwelling. It was fed with range cable. No alterations have been made. Do I need to install a EGC or is the existing installation ok as it stands?
    I can imagine a number of ways, involving the classic 60 Amp 240 / 120 Volt single phase fused panel, how said panel could become a subpanel, historically. There's a whole class of these panels that were manufactured with all of the neutral bus non-reversibly bonded to the steel enclosure. If the installation was actually inspected and approved (or appears to be) at the time of installation as a subpanel, it could, reasonably, be grandfathered in as wired to the Code of it's day.

    However, if, since that initial install as a subpanel, alterations and / or additions have occurred, then the alterations should have already dealt with separating the Grounded Conductor (Neutral) from the Equipment Grounding Conductor, regardless of whether you are leaving it untouched right now.

    That is, subsequent alterations and / or additions, under more modern Codes, to the "approved" subpanel may well have tipped the subpanel assembly into a violation status.
    Another Al in Minnesota

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