[quote author=t3zza36  link=1110492327/0#0 date=1110492327]replacing security light with pir which worked but on switch not sensor.only trouble is i have in light brown,blue,yellow/green but from switch i have red,blue,yellow,yellow/green,now i realise that 1 is secondary live but where does it go. [/quote]
Hello

Now assuming the brown/blue/G&Y are going to the light, this is 3-core flex, which will allow you to have you're light on or off, whilst this is turned off you're sensor will not work

what goes to the switch, or so it seems, is 3-core and earth flat cable, where you have red/yellow/blue/G&Y

One of them e.g. red will be a perminant live, e.g. not switched, another e.g. yellow, will be a switched live, allowing you're light to work off the sensor from the perminant live, and allowing you to manualy switch the light on from the yellow live cable

the blue is likely the neutral, and the G&Y will be earth, or should be, G/Y should always be an earth, and all floodlight's and external light's should be earthed

going by the limited information you have give, it seems to me that you have bought this light but wired it in flexible cable which now limit's you to what you can do, you need 4 core's in total, 2 lives, 1 neutral, one earth, otherwise you will need to leave the switch on for the light unit to work

AND

the live that run's in to the light (brown) MUST be in the perminant live, usualy marked 'L', if the brown cable is in 'L1' you're light will not function correctly

All the one's I've bought with an in-built PIR have had an L1 terminal for switch live lecc  

otherwise you can't latch it on, well you can do that silly switching on and off till the halogen wears out but it's proper naff

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I'll remember that, got to fit one of them sometime  
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