Transformer/Driver for 12v DC PIR motion sensors

Hi, I'm a newbie on this site and am working on a 12v garden lighting project. I will have 12v led lights along a path with a PIR sensor at each end of the path. Either of the PIR sensors will trigger the lights via a 12v relay. The PIR sensors will not be on the light circuit but on their own circuit. The question I have is what 12v DC transformer/driver spec should I buy to power just the pir's and the relay? The pir's will be approximately 30m apart and will have a very low load themselves (I can't find detailed specs for them unfortunately). I am planning to install 2.5mm2 conductor cable to help with the possible voltage drop over this distance. I hope this is clear, many thanks for any suggestions!
 
I can't see pir and relay taking much power I would imagine a 1 amp 12 volt supply would be plenty, might be an idea to have a diode reverse wired across the relay coil,as back emf can break things and give you a little shock
 
I can't see pir and relay taking much power I would imagine a 1 amp 12 volt supply would be plenty, might be an idea to have a diode reverse wired across the relay coil,as back emf can break things and give you a little shock
Thanks for the suggestion re. the diode - I'll look into this. I was concerned about the 30m or so distance between the pir's - with the cable I'm planning is this not an issue?
 

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