motion sensor and light switches how do you wire this up?

Discussion in 'Electrics UK' started by kevin1234, 23 May 2009.

  1. kevin1234

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    I am wondering is there any possible way of doing this,

    I have for lights in a room and i need to use a motion sensor as well as a light switch, but the customer is asking if it is possible for the lights to come on even if the light switch is off, and if you were to leave the room the lights would go off even if the light switch off!?? and also to operate the lights from the switch like overriding the Motion sensor

    Any wiring diagrams or any help of how i can do this?

    thanks
     
  2. Chri5

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  3. Spark123

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    If you wire it as 2 way it'll end up like a disco!

    It should be possible to use a 2 gang switch, one to override the PIR so the lights are permanently on and the other so that it kills the supply to everything.
    Is this what you are after?
     
  4. ColJack

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    wire the switch in parallel with the PIR live and switched live connection...

    that way the switch bypasses the PIR..
     
  5. Steve

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    I wouldnt wire a normal switch before the sensor, because when power is applied to the sensor they normally have to initialise, which involves coming on for 10 seconds, then going off, and returning to normal mode. No good really, unless you dont mind waving your arms at the thing to get it to come on.
     
  6. ColJack

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    they only normalise the first time you turn it on.. which would be done by the keyswitch in the 2G grid, or by the breaker..

    the "overide switch" would be in parallel with the feed and switched live on the PIR..

    you might also like to wire it with a timer / contactor in line with the overide switch being a push to make switch, to turn it off after hours..

    I'll do you a simle diagram and a complicated one and see what the client wants..
     
  7. kevin1234

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    Ye that would be great thanks if you could do a diagram for me, i aint that sure how to do it so thanks
     
  8. ColJack

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    simple drawing for now, if they want the timer etc to ensure no one leaves the switch on by accident then get back to us later..
     
  9. kevin1234

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    Ah nice1 coljack!! so i take it when the switch is off it just operates the lights through the PIR?

    Is it possible for you draw up one wit a timer etc in it please? that would be much appreciated!

    thanks
     
  10. ColJack

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    this would turn the lights on when the bypass button was pressed, but only during the hours set by the 24H timer ( ie during working hours ).
    at other times the light would operate on the PIR..

    the drawback is that once the bypass has been pressed, the lights remain on until the end of the day ( when the timer turns off )..

    for a more convenient way, use a normal switch instead of the push button and remove the contactor, connecting the output of the 24H timer to the lights directly

    this change however would mean that if the switch was left on, the lights would come back on in the morning..

    notes: "24H timer" is the switch contacts of a 24H timer, it will probably also need a live and neutral feed to it.....
    if omitting the contactor, the timer needs to be suitably rated to switch the lighting load..
     
  11. kevin1234

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    Ah thats good ye so i take it that the bypass button when pressed keeps the lights because of the timer is that right? and they wont turn off until the timer has timed out is this right?

    cheers
     
  12. ColJack

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    no, the contactor latches itself on.. the timer just turns the live feed to the contactor off so it drops out..

    ah whoops.. spoted a design flaw... :oops:

    I'll re-draw it.. :rolleyes:
     
  13. kevin1234

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    no problem is it possible for you to explain then what happens in the drawing how it works please
     
  14. ColJack

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    ah that's better...

    when you press the bypass button, as long as the timer is in it's "ON" state ( ie during the hours of business ) then the contactor comes on and closes all it's contacts.
    one of these contacts is in paralel with the bypass button, so its like someone keeping their finger on the button, the light stays on.

    with the timer in it's "OFF" mode, the switched live to the contactor coil is not connected, so it can't be energised..
     
  15. kevin1234

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    ah right i see, so when the timer is in the off position i take it the lights can still work via the PIR, and because you have the bypass button wired in parrallel, how does that keep the lights going

    and you see the first cable that goes into the contactor on the left hand side whats that for? im not that sure how the contactor is working here sorry if im annoying you here
     

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