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Thread: Limit to number of circuit breakers in panel

  1. #31
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    Quote Originally Posted by kwired View Post
    half size and tandems have been around for a very long time.

    I have a plant I do work in that has some tandem QO breakers in a couple places that I can almost promise you were original in the mid to late 1960's. They were non CTL type, but I believe the CTL requirement came later, like maybe 15-20 years later. If you used CTL rated ones you couldn't install anymore than the panel was designed to accept as they had a rejection feature for slots that weren't intended for them.

    Today a lot of the panels are designed to accept a tandem in every slot.

    With the AFCI requirements we now have for dwellings you don't see tandems being used, they haven't made any tandem AFCI's (so far) so that 40/80 panel is mostly still a 40 circuit panel in a dwelling. I suppose the mobile and manufactured homes are still using "quad breakers" for some 240 volt loads and there is a very small number of 120 volt circuits that don't require AFCI protection in a dwelling.
    CTL was added as Article 384.15 in the 1965 code.

  2. #32
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    Quote Originally Posted by Craigv View Post
    CTL was added as Article 384.15 in the 1965 code.
    OK.

    Pretty sure nobody was enforcing code around here back then either, so who knows how long it took for something like that to start being voluntarily complied with. Probably depends on when price of non CTL breakers went up enough to matter to the installer.
    I live for today, I'm just a day behind.

  3. #33
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    Quote Originally Posted by kwired View Post
    OK.

    Pretty sure nobody was enforcing code around here back then either, so who knows how long it took for something like that to start being voluntarily complied with. Probably depends on when price of non CTL breakers went up enough to matter to the installer.
    This took a long time to implement. Non-CTL loadcenters weren't produced after 1965, but given available stock, availability of non-CTL breakers, and how long it takes to replace an existing fuse/breaker panel, this took decades. I service a campground that has cabins, restrooms, pumphouses, etc. that still have non-CTL loadecenters.

  4. #34
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    Square D has 60 and 80 space homeline loadcenters.

    I think the NQ panelboards and QO loadcenter max is 72 spaces.

    I’ve used a few of the 60-space loadcenters on larger homes that only need a 200A service.


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  5. #35
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    Quote Originally Posted by brantmacga View Post
    Square D has 60 and 80 space homeline loadcenters.

    I think the NQ panelboards and QO loadcenter max is 72 spaces.

    I’ve used a few of the 60-space loadcenters on larger homes that only need a 200A service.


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    Not certain about loadcenters, but I have used 84 space NQ before.
    I live for today, I'm just a day behind.

  6. #36
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    Quote Originally Posted by zbang View Post
    Sure, "What is 6 times 9?"



    (Yes, the answer is 42.)
    Ummmm... no. 6 times 7 is 42. I had to check it on my calculator; it's been a long time since the 4th grade.

  7. #37
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    Quote Originally Posted by ggunn View Post
    Ummmm... no. 6 times 7 is 42. I had to check it on my calculator; it's been a long time since the 4th grade.
    It's an inside joke. A reference to Hitchhiker's Guide to the Galaxy.

  8. #38
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    Quote Originally Posted by kwired View Post
    Not certain about loadcenters, but I have used 84 space NQ before.
    I was completely wrong on both ...

    NQ goes to 84

    QO goes to 54 with plug on neutrals in MLO on single phase, 60 in MCB, and the old style QO only goes to 42.

    Seems odd they only show 54 circuits in the MLO; I thought all of their QO loadcenters had field convertible mains and used the same bus.


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  9. #39
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    Quote Originally Posted by Carultch View Post
    It's an inside joke. A reference to Hitchhiker's Guide to the Galaxy.
    Oh, I got that, it's just that 6 times 9 isn't 42.

    So long, and thanks for all the fish.

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