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Quick Fused Connection Unit query on a spur....

Discussion in 'Electrics UK' started by Funkyfreddy, 17 May 2016.

  1. Funkyfreddy

    Funkyfreddy

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    Quick query please guys...

    I have a Spur coming off a Ring Main (Junction Box). This supplies a Switched, fused connection Unit which itself supplies a Alarm panel under some stairs.

    I'm wanting to put a light source (2ft 18W Tube) in there with this Spur being the only real option.

    Can I tag the supply for the light from the load on the FCU with the Alarm – if so down side to that is that the light can't be on with the Alarm off for any work on that.

    Can another FCU be daisy chained from the “Supply” side of the current FCU – that would result in two FCU's on the Spur but allow each device (Alarm and light) to be isolated at each FCU ?


    Thanks.
     
    Last edited: 17 May 2016
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  3. ban-all-sheds

    ban-all-sheds

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    Yes, you could do either.
     
  4. Funkyfreddy

    Funkyfreddy

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    Thanks for the quick reply b-a-s's

    Second option then - at least there will be a light source for working on the alarm

    For the sake of asking could the Light be fed from the "Supply" side of the existing FCU but effectually making a direct connection the the ring with no protection other than the Ring MCB ?

    Thanks again.
     
  5. Deryck Tintagel

    Deryck Tintagel

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    You need to change the switched FCU to an unswitched FCU for the alarm panel
     
  6. ban-all-sheds

    ban-all-sheds

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    No, you should have an FCU for the light. You're going to need a switch anyway, so....
     
  7. ban-all-sheds

    ban-all-sheds

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    Why?
     
  8. Funkyfreddy

    Funkyfreddy

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    Doh - just use the FCU as a switch then. Simples !

    Thanks.
     
  9. Gteuk

    Gteuk

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    I am assuming it is a burglar alarm and not a safety alarm (Fire / CO) so not required.
    I would say it would be a nuisance if the RCD trips though as most alarms have battery backup and sounds on loss of power.
     
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  11. Funkyfreddy

    Funkyfreddy

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    Thanks for the continued input.

    Gteuk, just a burglar alarm however am now thinking of making that an unswitched FCU to avoid it being turned off unintentionally.

    Feed to a switched FCU to act as switch for the light but alarm cab be isolated if need be for work.

    Rgds
    FF
     
  12. Taylortwocities

    Taylortwocities

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    I do not know what the requirements are for alarm panel isolation (anybody?).
    If they need a double pole isolator then you must use a switched FCU.
     
  13. Risteard

    Risteard

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    I suspect that if you do not have an UNSWITCHED FCU, and with NOTHING ELSE connected to it that you will not be in compliance with BS EN 50131.
     
  14. Funkyfreddy

    Funkyfreddy

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    Crikey - thanks again for the input.

    OK - was going to settle for:

    Spur from a Ring - via a Junction box not a socket.

    This Spur to lead to a unswitched FCU to avoid unintentional switch off which will provide a supply to a Burglar Alarm

    Daisy chained from the unswitched FCU a Switched FCU which will provide a supply to, and act as a on/off switch for a 2ft/18W fluorescent tube.

    Good to go ?

    Rgds
    FF
     
  15. Gteuk

    Gteuk

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    That totally depends on the install method, the risk and who installed it ?? the standard is set to more high end alarm systems and not so much off the shelf products
     
  16. securespark

    securespark

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    As you have to get an FCU for the new light anyway, just fit an unswitched FCU for the panel and use the one you take off to control the new light.
     
    Last edited: 18 May 2016
  17. securespark

    securespark

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    On a very simple level, you don't want anyone switching it off by mistake, leaving the onboard battery to take over, run down and the SCB to go into alarm condition.
     
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