Fitting a PIR into existing porch lights?

[macman]

Hi Guys,
Question: I have two external lights, currently activated by one switch in my hallway. I have a separate PIR unit bought a loooong time ago, and wonder if it can be wired into the lights so it activates them automatically for a while when people come home late (and currently forget to switch them off!).

Does anyone think this might be possible? I guess I'd have to leave the switch in place and 'on' permanently, as to remove the current wiring would be messy to say the least.

The lights currently use 'long-life' bulbs, but any eco saving is probably outweighed by the fact that the darn things get left on most nights!
Is this a possibility?

Thanks in advance for any suggestions (and maybe a simple wiring diagram??)
It's something I've meant to get round to for ages, but you know how it is...

 

[securespark]

Basically, if you are not going to alter anything inside the property, then you will need to leave the switch down to keep the PIR powered up. Then take a live feed & neutral to the passive & a switched return back to the light.

However, if you can access all the wiring connections for the light you need to control, then you can use the existing one way switch as an override, providing it has a twin & earth between the switch and the light position / junction box. You must make provision for isolation though.

Then it's just a case of running a 4core flex to the passive from the light / jb as in the previous scenario.

 

[macman]

Thanks for the advice. I'll see what I can do!