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Fire Alarm Panel Electrical Isolation.

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Is single pole electrical isolation suggested here even if we are going to prod and poke about inside the fire alarm panel? And, what are the two fuses removed mentioned all about? Is the lecturer confused?


Please see 41.12 onwards.

https://www.bing.com/videos/search?q=youtube+bs+5839+part+1&&view=detail&mid=92E9069FDA874942E42A92E9069FDA874942E42A&rvsmid=7BBC139314220094A9417BBC139314220094A941&FORM=VDQVAP


Z.
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    The pulling 2 fuses thing is not right as he describes it - that is not what we mean by 'double pole' isolation (i.e. breaking L and N together ), what he seems to mean is isolating in 2 places. (a variation on double fault to danger - you have to break the wrong circuit, in 2 places to reach a dangerous condition - bit like cascade RCDs)

    I presume single pole isolation, from the sparks perspective, is only OK when you have a solidly earthed neutral, and or a 3 phase system where you would not want a switched neutral.

    Mike.



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  • 0
    The pulling 2 fuses thing is not right as he describes it - that is not what we mean by 'double pole' isolation (i.e. breaking L and N together ), what he seems to mean is isolating in 2 places. (a variation on double fault to danger - you have to break the wrong circuit, in 2 places to reach a dangerous condition - bit like cascade RCDs)

    I presume single pole isolation, from the sparks perspective, is only OK when you have a solidly earthed neutral, and or a 3 phase system where you would not want a switched neutral.

    Mike.



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