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Thread: Switchgear vs. Switchboard

  1. #1
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    Sep 2003
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    Switchgear vs. Switchboard

    Can anyone tell me the difference between switchgear and switchboard?

  2. #2
    Guest

    Re: Switchgear vs. Switchboard

    In my personal lexicon switchgear would be anything that goes in a switchboard. The switchboard would be the vessel, and the switchgear would be the contents of the vessel.

    Switchgear= circuit breakers, fuses, switches, etc.

    [ September 30, 2003, 04:53 PM: Message edited by: awwt ]

  3. #3
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    Re: Switchgear vs. Switchboard

    Thaks for your response. But it doesn't seem like the answer. If you look up the any equipment catalog for instance Square D, they show it as a factory assembled unit just like a switchboard.

  4. #4
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    Re: Switchgear vs. Switchboard

    From article 100 (always a good place to start)

    Metal-Enclosed Power Switchgear. A switchgear assembly completely enclosed on all sides and top with sheet metal (except for ventilating openings and inspection windows) containing primary power circuit switching, interrupting devices, or both, with buses and connections. The assembly may include control and auxiliary devices. Access to the interior of the enclosure is provided by doors, removable covers, or both.
    Switchboard. A large single panel, frame, or assembly of panels on which are mounted on the face, back, or both, switches, overcurrent and other protective devices, buses, and usually instruments. Switchboards are generally accessible from the rear as well as from the front and are not intended to be installed in cabinets.

  5. #5
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    Re: Switchgear vs. Switchboard

    It still looks same to me. Can you please explain to me in layman's term?

  6. #6
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    Re: Switchgear vs. Switchboard

    Do not take this as an official definition.

    When I hear switchgear I think of voltages, above 600 volts. In large commercial work you may have 13.8 KV coming inside the building, many times two circuits from different POCO supplies so if one fails the other takes over the load automatically or manually.

    In this gear is high voltage breakers, current and voltage meters, ground fault detection equipment and meters for billing.

    When I hear switch board I think voltages under 600 volts and basically a bunch of panels mounted in a common enclosure.

    But that is just my experience, it is certainly not the only way to describe this equipment.

    -Bob

  7. #7
    Guest

    Re: Switchgear vs. Switchboard

    Originally posted by iwire:
    <snip> Metal-Enclosed Power Switchgear. <snip>
    If you take "Metal-Enclosed Power" out of the term then my description holds up. In the trades switchgear is used as a generic term.

    Thanks for nailing it down with an NEC cut/paste. Your answer fits the question better.

  8. #8
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    Re: Switchgear vs. Switchboard

    Simple answer:

    Switchgear is built to ANSI standards (C37C37.20.2), although UL now has some input. Typical requirements include: Drawout breakers, fully compartmented construction (grounded metal barriers around all live parts), automatic shutter, insulated bus bars, mechanical interlocks.

    Switchboards are built to UL standards (UL891). Basically these are large panelboards.
    Just because you can, doesn't mean you should.

  9. #9
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    Re: Switchgear vs. Switchboard

    The ANSI and UL standards to which each is built is the key.
    For the most part, they are becomming more and more inetrchangable, as you can now get drawout breakers, 30 cycle short circuit ratings and 200kAIC on switchboards where you would have been relegated to switchgear in the past.
    Ron

  10. #10
    Join Date
    Sep 2003
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    117

    Re: Switchgear vs. Switchboard

    Your answers helped me a lot. But there is still one thing that I don't understand. If they are interchangable and perform a lot alike, why do they have different standard at first place? What would be the "rule of thumb" or the best example application that you have to use a switchgear instead of a switchboard?

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