Last man out

Discussion in 'Electricians' Talk' started by oscar21, Nov 3, 2010.

  1. oscar21

    oscar21 New Member

    How to wire a last man out switch with non maintained emergency lights.

    The last man out switch operates 2 contactors, however the problem was keeping the em lights powered, I know I could come straight out of the rcbo before the contactor but my concern was if the contactors failed the emergency lights would not operate.

    So this is how I did it.

    http://yfrog.com/9gimg024llj
     
  2. spark&half

    spark&half Active Member

    Well it depends on your question really?

    Was you adding a switch to an existing setup or was you wiring from scratch?

    If you was wiring from scratch

    you could have had a 3core and earth going to each area of lighting looping in and out of each fitting (via a klick plug-in system)

    live = brown
    black= Em Feed
    grey = neutral

    brown would then be dropped down at every light switch for local switching etc etc.

    just run this lot thru the required amount of contactors just switching the browns.

    Also connecting the Em feed to the live sides of the contactors leaving them permanently on (obviously feed via a Em key switch for test purposes).

    Then just have your master switch controlling the contactors A2.

    Probably doesn't sound clear but its a very simple way of wiring this kinda setup.

    Perhaps be better showing you on a drawing.

    ;)
     
  3. smallvile

    smallvile New Member

    are the em lights wired as a seperate circuit?
    could you not use a n/c contactor operate the coil through a key switch?
     
  4. J.P.

    J.P. New Member

    Be blowed if I understand any of it tbqh. Why does it have to be so complicated?
     
  5. sinewave

    sinewave Screwfix Select

    Kinnel JP if ya think that's complicated U wanna try fault finding some commercial BMS panels! :(
     
  6. Lectrician

    Lectrician Screwfix Select

    Does seem a tad over engineered.
     
  7. oscar21

    oscar21 New Member

    As I said, doing it the simple way if the contactor for the lighting was to fail the emergencies would not illuminate. Just wanted to foolproof it.
     
  8. Caddy

    Caddy Active Member

    So you wired the EM Lighting through a sepearate contactor in case the main lighting contactor failed.. Isnt there a slight floor in that logic..
     
  9. oscar21

    oscar21 New Member

    Not really, if the em contactor fails then the em lights will be on.
     
  10. spark&half

    spark&half Active Member

    Lets not make things complicated by worrying about "what if's" if a problem happens then an electrician will come out to fix it simples....

    You cant future proof every possible scenario it wouldn't be practical.

    Do you fit another emergency light next the original emergency light just in case it stops working??

    Now come on guys grow some please will ya and get on with the job in-hand.

    ;)
     
  11. oscar21

    oscar21 New Member

    Another good thing, all the emergencies can be tested from one point.
     
  12. Lectrician

    Lectrician Screwfix Select

    IMO you have just created more too fail.

    Switching the switch will also flick the supply momentarily to the EM's. Not particularly ideal.
     
  13. RTCELECTRICAL

    RTCELECTRICAL New Member

    Please Note:

    THE LAST MAN OUT SWITCH is copyrighted, trademarked, and owned by *- *



    regards

    *

    Message was edited by: Screwfix Moderator
     
  14. sparky Si-Fi

    sparky Si-Fi Screwfix Select

    So sue awaaaaaaaaaaaaaaaaaaaaaaaaaaaay!
     
  15. stateit

    stateit Screwfix Select

    RTC Electrical: From your website -"The latest report estimates that between 17% to 20% of your power is used by standby equipment..."

    Bit of a dodgy claim isn't it? What excatly is this 'latest report'?
     
  16. unphased

    unphased Screwfix Select

    It's spam. Don't bother with RTC. Just another spark spamming the forum.
     
  17. spinlondon

    spinlondon Screwfix Select

    Use a dali type lighting system.
     

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