Isolation Switch For Twin Security Lights Emanating From One Circuit Question

Discussion in 'Electricians' Talk' started by J.P., Sep 27, 2013.

  1. J.P.

    J.P. New Member

    Morning lads..:) Please see photo : -


    Basically the security lights will be switched on a L1/L2 basis -  L1 being normal operation, and L2 being override

    Yes for maintenance purposes I would be happy to defeat power using Mcb at DB position, however this does not comply with readily accessible local isolation regulations. Thus what do you guys think of the above which will hopefully satisfy my de-rigueur electrical inspector (good geezer). Thanks Lads
  2. FatHands

    FatHands Well-Known Member

    Morning JP,

    Looks good to me. I am sure i have seen similar set-ups (with over-ride) where the FCU was not in the same location as the L1/L2 and was passed.


  3. J.P.

    J.P. New Member

    Cheers Fats. You mention FCU. Maybe I should substitute the 10 Amp Switch with one of those because it might be possible to accidentally knock the switch on which would not be good if doing stuff on the lights etc. The fuse could be popped prior to said - thus negating power in a safe manner (not possible to accidentally energise) Good call Fats and will use what you say. Thanks m8.
  4. retiredsparks

    retiredsparks Well-Known Member

    I have checked the regs and studied your cct arrangement thoroughly !
    My opinion is that 'de rigueur' should be replaced with 'rigouous' or even' pedantic' (if budget will run to it) or at least 'punctillious'.;)
  5. J.P.

    J.P. New Member

    Many thanks RS - all grammatical points noted m8 - ;):)
  6. FatHands

    FatHands Well-Known Member

    No problem JP, yeah sounds like a plan mate.


  7. Lectrician

    Lectrician Screwfix Select

    You love to seem to confuse with the L1 L2 thing JP - I seem to recall this before.

    If it was me, I would have fitted a double back box, and then used a three module grid assembly.  Key operated switch as the isolator, and then two single pole switches for the override (no point removing power from the sensor when in override IMO).  I may even have used the MK DP switches with the neon on the top of the rocker.

    I aassume you want to drop the sensor power off when running on override to allow a 'reset' period for the sensor should it latch on due to quick operation?  Even so, this could easily still happen, and the main isolator would cure that.

    Key switch and two rockers for me, all on a tidy single plate.
  8. Whome?

    Whome? New Member

    As Lectrician said you could have made things a lot simpler by using a 3 gang switch plate, but either way I'm not sure why you believe you need to have " readily accessible isolation " for the outside light. For one its not local to the outside lights. Since its not local to the lights you should be able to lock it in the off position to prevent someone turning it on whilst your working on the light. Since you can lock off an MCB that would be the point at which to safely isolate the circuit..
  9. J.P.

    J.P. New Member

    Evening Lec and Whome. Must admit Lec didnt know about the gridswitch in double backbox so that's handy for if I ever do that kind of thing again. With ref to the L + L2 Lec : -  3c + e to each light -  obviously L1 being normal operation, and L2 a direct feed to the lamp which bypasses the PIR - switching back down to L1 brings it to normal security operation.

    Thus the need for the defeat switch to both lights as someone might switch it off but in realty there is still juice on the lamp.

    With ref to Whome and the mcb isolation - m8 I would love to do that but I think the inspector will pull me on it..thanks Whome and Lec.
  10. Lectrician

    Lectrician Screwfix Select

    THree core to light, via PIR.

    Brown perm live via isolator, black switched live on pir, which you make live with your override switch.  The L1 L2 toggle switching is just confusing IMO.
  11. J.P.

    J.P. New Member

    Cheers Lec see what you mean m8.

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