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Panelmount switches: how many ONs and OFFs?

Discussion in 'Electrical Engineering' started by qmu, Nov 10, 2008.

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  1. qmu

    qmu Guest

    Hi all,
    I have some troubles with an electrical plant and I have to turn
    electricity on and off many times per day from a C16 breaker +
    differential breaker (I hope the English terms are correct), panelmount,
    220V. How many ups and downs is such a thing expected to withstand?

    Is it better to trip it down with the differential breaker test-button
    or with a finger?

    Alternatively, I could trip this electrical counter
    but I would prefer the C16/differential because it is mine. Unless you
    tell me that this counter is expected to withstand really many more ons
    and offs.

    Thanks in advance
  2. Twayne

    Twayne Guest

    Hi all,
    I doubt there would be any difference but have no direct experience that
    Normally, not many w/r to using it as an on/off switch if it isn't
    designed to do so normally. I can't get my head around exactly what you
    have but I assume it has to have a breaker-like action to it. That is
    always advised against. Unless you have a breaker made spefically to
    withstand that kind of use, you should find another way. The bimetal
    strengths change due to the stress-activity and the contact surfaces
    wear (arc) and corrode very quickly under constant switching conditions.
    With a run of the mill breaker, you may get anywhere from one or two
    more switches with it to a month or more before it starts to run into
    false-overload trips, heating issues, even in some very seldom occurring
    instances, a failure to trip until the I gets substantially above the
    rated current (contact welding, in other words).
    Based on the lack of information given, you would have to check with
    the mfg of the part. That's a much better source than a newsgroup
    anyway, where each poster, including me quite often, feels that their
    own experiences are "typical".

  3. qmu

    qmu Guest

    Thank you for your really thorough reply.

    The C 16A + differential breaker I have is an ABB DS642
    It is roughly similar to the one in the first picture here
    except that I can't see the test button in the picture. The
    "differential" thing I was talking about was probably a mistaken term,
    now I understand that the english name is "Earth leakage circuit
    breaker" (ELCB), so mine would be a "C-curve 16A + ELCB breaker".

    Today I went around on the Internet looking for the specifications of my
    breaker, as you suggested. I couldn't find them for that breaker
    exactly, however many breakers of that class seem to indicate that they
    have "mechanical (service) life" of 20,000 operations, and an electrical
    service life of 10,000 operations.

    E.g. here:$file/Line+Protection+Devices.pdf

    Now I don't understand anything anymore.
    Is the "service life" the value I am looking for, or is it something else?
    Do you think it is overstated?

    What is the difference of mechanical vs electrical service life? Am I
    correct saying that if I am pressing the test button or going over 16A
    and it trips, that is electrical, while if I pull it down with a finger
    that is mechanical?

    Thanks for your help
  4. qmu

    qmu Guest

    This is useful information
    Now I am switching it off with the finger. And before doing that I turn
    off every electrical load in the house, so that current does not pass
    through the thermomagnetic switch while I am switching it off or on. In
    this way there should be no spark...
    Thank you
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