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Help wiring DPST Switch

Discussion in 'Datasheets, Manuals and Component Identification' started by Chris Bargman, Mar 1, 2016.

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  1. Chris Bargman

    Chris Bargman

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    Mar 22, 2015
    I have this switch: http://www.mouser.com/ProductDetail/Marquardt-Switches/15553108/?qs=4EOvy6wCNnuMsLtaOnPuvA==

    I've looked at the datasheet and I just can't seem to figure out how to wire it so that the LED will light up when the switch is in the on position. Most illuminated switched I have used have 3 terminals but this one has four and they seem to only control the devices that are plugged into it.

    I have tried every combination of terminals I can think of.

    I am wiring it to a 12V DC Source in a car.
     
  2. TeslaCoil

    TeslaCoil

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    Mar 1, 2016
    This is not the switch you want if you expect it to light up.
    I think you'll find it's not an LED but an neon.
    The switch is rated at 250v. The light will have a resistor related to that voltage.

    Although you could still use the switch for 12v. It will not operate the light.
     
    Last edited: Mar 1, 2016
    davenn likes this.
  3. davenn

    davenn Moderator

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    @TeslaCoil is correct in his comments

    it will be wired like this .....
    as in the Live and Neutral will both be switched

    switch.GIF


    Dave
     
  4. Chris Bargman

    Chris Bargman

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    Mar 22, 2015
    Okay thanks!
     
  5. Tha fios agaibh

    Tha fios agaibh

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    Aug 11, 2014
    Nice sketch Dave.
    But It should be noted that switching the "grounded" conductor (neutral) is prohibited per NEC 404.2(b)
     
  6. davenn

    davenn Moderator

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    That must be a USA thing
    It's pretty standard practice on lots of equip in this part of the world
     
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  7. TeslaCoil

    TeslaCoil

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    Mar 1, 2016
    I think what it says is that you shouldn't use the neutral alone to turn off a circuit, however if switching the neutral is combined with switching the live then that is ok. In this case a double pole switch would be fine.

    Also, the original request Is about 12v dc, so the NEC 404.2(b) rule does not really apply - although it is still good practice to a switch the live.
     
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  8. dorke

    dorke

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    Jun 20, 2015
    We shouldn't confuse the Neutral with the Ground.

    Ground switching isn't allowed anywhere on earth!
    Ground should be permanently connected for safety reasons.

    Neutral switching for power applications like electric water boilers etc. is a good practice for safety reasons,
    in some places it is mandatory.

    Neutral switching for lighting uses is allowed but not always necessary .

    and here is the link to that switch datasheet,it clearly shows the electric diagram (mid-right)
     
    davenn likes this.
  9. Bluejets

    Bluejets

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    Oct 5, 2014
    Double pole switching primarily for portable mains powered equipment and things like caravans.
     
  10. Tha fios agaibh

    Tha fios agaibh

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    Aug 11, 2014
    No one said ground. I said:"grounded conductor" referring to Dave's sketch.
    Technically it's not a neutral at all. It's a grounded conductor. But many slangly call it a neutral.
    Yes, there is an exception to 404.2(b) for disconnecting supply power but I disagree with your assertion that it is a good practice or safer. If the "neutral" were to get disconnected while the hot doesn't (contact fails) it may cause a situation where fault currents will take rogue paths back to its source without tripping a breaker. Also in a multiphase applications loosing the neutral will cause the circuit voltage to change erratically because it lost its reference point. So it is a better and safer in most situations to keep the neutral connected throughout the circuit.
    Other than the exception alowing disconnecting a neutral simultaneously or after the ungrounded (hot) for main power purposes, 404.2(b) is, and has been a rule for many years, and for very good reasons.
    Btw, the German diagram shows 1 an 2, not L and N

    Of course this is not relevant to the op if he is wiring up a car.
    But it someone was to want to wire the light switch in their house, it would definitely be a violation.

    John
     
  11. dorke

    dorke

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    Jun 20, 2015
    John,
    Are you talking about a 2 prong power connection?
    I'm referring to 3 ,the 3rd being the dedicated ground.

    Where do you see ground or anything grounded in Dave's diagram?

    Yes the switch uses "terminals 1 and 2" because you can connect it anyway you like.
     
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  12. 73's de Edd

    73's de Edd

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    Aug 21, 2015
    Sir Chris Bargman . . . . . . .


    "Although you could still use the switch for 12v. It will not operate the light."


    Leaving the . . . . . . illimination at a 12VDC level . . . . . . still withstanding

    Thereby:

    1 . . . . . Needing to return and get the PROPER unit with its design incorporating an internal LED and its dropping resistor for 12 VDC operation .
    2 . . . . .Using the switch that you might now be "stuck with" and the additional mounting of an external LED and its dropping resistor, external of the switch and having the LED "peep" thru a hole just aside to the switch near the rockers "on" position.
    3 . . . . .Experiment in the possibility of the drilling of an approximate 1/8 inch hole within the rear backplate of the switch and let the tip of a small, HI intensity LED, dump its illumination into that recess to
    flood the inside of the switch in order to illuminate in a power on state.


    73's de Edd
     
    Last edited by a moderator: Mar 3, 2016
  13. davenn

    davenn Moderator

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    Sep 5, 2009
    there is no stated ground in my sketch ;)
    just live and neutral

    anyway Dorke covered the rules which also apply in Oz and NZ
     
    dorke likes this.
  14. Tha fios agaibh

    Tha fios agaibh

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    Aug 11, 2014
    No, I'm talking about the practice of switching a neutral (grounded) thru a switch. Not a 2 or three prong plug.

    Ok, your talking about the dedicated ground. And....? (Btw, North America we refer to it as an equipment ground.)

    In Dave's diagram he labeled one pole of the switch "N" which refers to neutral. This "N" is an intentionally grounded system conductor (white wire) over here, similar to your (blue wire) common on your side of the pond. It is not the same as an equipment or chassis ground.

    I was merely pointing out that in NA (home of op who asked how to wire the switch) It is illegal to switch off the grounded neutral in most instances.

    The only reason I mentioned the sketch you posted, is because you said "it clearly shows diagram.." which I interpreted as claiming: switching "N" is alowed as shown in diagram.

    Disconnecting or switching a "N" can be just as dangerous as disconnecting an eq.gound. that's why its not allowed per 404.2(b) of the NEC.
     
  15. Tha fios agaibh

    Tha fios agaibh

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    Aug 11, 2014
    Yes there is. The "N" is a grounded conductor!

    Also, it's not a neutral.
    A neutral is a grounded reference point between two or more ungrounded (hot) phase conductors.
     
  16. dorke

    dorke

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    Jun 20, 2015
    Like Dave said before,it must be a US thing.
    It is invisible to the earthlings on the other side of the pond,sort of a blind spot I guess;)
     
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  17. davenn

    davenn Moderator

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    its only grounded at the fuse panel at the house entry

    and in most of the English speaking world, its called neutral


    please stop arguing !!


    Thread closed before it sidetracks further
     
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