Wiring an additional PIR sensor

TaffyBoy · Oct 30, 2012

I am in need of some help. I have a security light which has a built in pir sensor. I have bought and additional one that I want to wire in to cover an additional area at the front of my house.
The existing light has only two wires coming out of it, a live and a neutral, that go into a choc block fed from a mains switch in the house. Now the new standalone pir sensor has 3 wires from it into a choc block, live, L1 and neutral.
How to I wire it in?

Many thanks.

SPARTYKUS · Oct 30, 2012

As described, you can't wire it to work as you'd hope.

You can only supply power to the stand alone PIR and that could trigger the other one (pretty pointless).
You need access to the wiring "further in"

TaffyBoy · Oct 30, 2012

So I can't just connect the extra sensor Simply to have the 2 of them working?

SPARTYKUS · Oct 30, 2012

Not with the wiring described, no. You need to be able to wire the new PIR in parallel to the PIR mechanism of the combined light & PIR. So that either PIR will switch the light on, presumably.

You'd also need to supply power to both units.

TaffyBoy · Oct 30, 2012

Hmm ok. Think it will just be easier to buy an extra light. Thanks for the replies.

SPARTYKUS · Oct 30, 2012

No probs. can you see any more wiring further in?

TaffyBoy · Oct 30, 2012

Nope, there's just a 3 core cable coming out from the inside of the house and that's it. I needed the 2 sensors as I wanted one to focus on my steps and the other to focus on my door step. I'm thinking it may just be easier to buy a solar pir light to light the one area and leave the existing mains powered light to illuminate the other.

ayjay · Oct 30, 2012

it can be done taff but as spartycus says, you will have to get to the internal switched output from the inbuilt sensor

TaffyBoy · Oct 30, 2012

If I find that wire can I just connect into that line then and run it from the inbuilt sensor in the light to the L1 terminal in the standalone pir sensor?

ayjay · Oct 30, 2012

it should be fine taff, all it is -is another switched contact in parallell you could add even more pir,s if you wanted too

TaffyBoy · Oct 30, 2012

So, just to be sure. (I'm a complete novice with electrics).

I can put a connector block in the switched live wire coming from the Inbuilt pir, and join a wire from there to the L1 terminal at the standalone pir. Then connect a neutral and a permanent live to their respective terminals on the standalone pir and then both pir's should operate the single light whenever either detect movement?