New PIR lights off of photocell

[daveb]

Hi chaps,

Went to look at a job tonight in my town - client has an existing photocell sensor doing her outside lights with from what I can see is a three core and earth feeding it. As it's difficult getting back into the home for power, they asked if it was possible to get power from the photocell to then feed the two new PIR lights.

As I can only see one three core and earth cable going to this sensor, am I right in assuming that it's probably been wired via a light switch in the house? I.e. There will be a perm live and neutral to operate the photocell with the switched live (live out) back via a switch somewhere that then goes to the outdoor light fittings? Otherwise, (and the way I have sometimes seen them wired) you would see two cables coming out of the photocell - one for your power in and the other cable for your power out to the light?

Cheers

 

[telectrix]

feed the pir from the photocell. L, N and s/l just using the 3 core/e that's there. then the pir will be in parallel to the manual switch.

 

[daveb]

feed the pir from the photocell. L, N and s/l just using the 3 core/e that's there. then the pir will be in parallel to the manual switch.

That's what the plan is - but do you think it has been wired back via a switch seeing as there is only one cable? Is this normal rather than having a cable into the photocell then out to the lights? Thanks

 

[Toneyz]

I wouldn't try to get two cables in the photocell (if it's the one I'm thinking of) make the existing cable off in IP rated box, feed photo cell off that and then feed new lights from the IP adaptable box.

 

[westward10]

Agreed.

 

[daveb]

Thanks guys - this is what I was planning to do. I was more wondering how the previous electrician would have wired the outdoor lighting if there was only one cable to PIR? Would they have taken the PIR back to the switch and tied the lighting switch wire in with the switched out on the PIR? Does that make sense?

 

[Richard Burns]

There could have been a light in place beforehand just wired on a switch and then someone added a photocell on its own cable and made all the connections at the switch.