Wiring outside light off existing outside light

[philly1]

Hello, probably a dull question, but I already have a motion sensor outside light installed and just wondering how easy it is to wire another one off the same light further along the wall (so that they both come on when the motion sensor in the existing light is activated)? Is it just one cable needed the between the two or is it a bit more complicated!? Will ask an electrician to connect them up if it's complicated but hoping to get the cabling ready at least. Thanks

 

[EFLImpudence]

It would be easy to do,

but - your present light might not have the necessary accessible switched live connection.

 

[philly1]

Thanks, is it just 1 twin and earth 1.5mm cable needed between the two?

 

[JohnW2]

Thanks, is it just 1 twin and earth 1.5mm cable needed between the two?

That cable would be adequate. However, as EFLI has said, it would only be possible if a switched live (switched by the motion sensor) connection were available at your present light fitting (which it quite probably is), since what you need to connect to the additional light is a neutral and a switched (by the motion sensor) live. If all you had accessible were an unswitched live (i.e. the connection supplying power to your present fitting), the new light would be on continuously/permanently.

Could you provide us with a photo of the connections in your existing light fitting?

Kind Regards, John

 

[winston1]

Thanks, is it just 1 twin and earth 1.5mm cable needed between the two?

You don't need 1.5mm cable for lights, 1.0 mm is adequate, cheaper, and saves the worlds valuable resources of copper.

Having said that twin and earth is NOT suitable for outside use anyway.

 

[philly1]

Thanks for the replies, its something like this:

https://www.amazon.co.uk/Bulkhead-Fitting-Motion-Detector-Sensor/dp/B01M1EO10Z

The motion sensor isn't built in as such so guessing the wiring is easily accessible inside.

I'm looking to wire one (or maybe two) of these off it:

https://www.screwfix.com/p/lap-bron...gclsrc=aw.ds&dclid=CKqE89OQ09gCFYi1UQodk5YI0Q

Would it just be 1 cable from the existing one to the new one, then 1 cable from new one to 2nd new one?

It's a bit fiddly where I'm going to be running the cabling why I'm looking to do it ready for the electrician save a bit of his time and my money! I'll secure and wire the new ones ready and let him check it and connect to the existing one

 

[EFLImpudence]

The motion sensor isn't built in as such so guessing the wiring is easily accessible inside.

I would agree.

Would it just be 1 cable from the existing one to the new one, then 1 cable from new one to 2nd new one?

Yes.

 

[philly1]

Great, thanks for your help

 

[JohnW2]

Thanks for the replies, its something like this: https://www.amazon.co.uk/Bulkhead-Fitting-Motion-Detector-Sensor/dp/B01M1EO10ZThe motion sensor isn't built in as such so guessing the wiring is easily accessible inside.

It isn't really clear as to whether that one (or one 'like it') has the ability to power ('switch' additional lights), particularly since it's an LED one (is yours?). As I said before, a look at the connections might give us at least a clue.

I'm looking to wire one (or maybe two) of these off it: .... Would it just be 1 cable from the existing one to the new one, then 1 cable from new one to 2nd new one?

Yes, IF the existing one provides the required connection then just that one (or two) new cables would be all that would be required.

Kind Regards, John

 

[JohnW2]

I would agree.

I'm wondering how inevitable that is. ....

.... In the good-old (pre-LED) days, one would expect the PIR module to have a relay output with a switched-live capable of switching appreciable additional loads, and a connection to that S/L provided. However, if it's just an 8W LED light, it's at least possible that there is just 'electronic' switching, with little or no capacity (or provided connections) for switching anything additional. I therefore think one would have to look at the spec/instructions for the actual fitting concerned in order to be sure.

Kind Regards, John

 

[EFLImpudence]

I'm wondering how inevitable that is. ....

This was just referring to the accessibility of the wiring.


You might be right about the capacity - although 8W + another 10?

 

[JohnW2]

This was just referring to the accessibility of the wiring.

Yes, I realised that, but ....

You might be right about the capacity - although 8W + another 10?

Yes, the additional capacity would presumably not be an issue. However, I was thinking more laterally than that. If the PIR of the unit is switching just a low-power LED, then it may not have a relay, but just semiconductor switching with a pretty low capacity. If that were the case, it's not impossible that they have deliberately failed to provide an easily-accessible S/L, lest someone tries connecting significantly large additional loads (in those 'olden days', one expected to usually have a relay output capable of switching 1,200W or 1,500W).

I just don't know, but I'm suggesting that one should not regard it as a foregone conclusion that an PIR+low-power-LED combination will provide access to a S/L.

Kind Regards, John

 

[EFLImpudence]

I just don't know, but I'm suggesting that one should not regard it as a foregone conclusion that an PIR+low-power-LED combination will provide access to a S/L.

...but the wiring from the PIR to lamp runs through a tube, so I don't see how it cannot be accessible.

 

[JohnW2]

...but the wiring from the PIR to lamp runs through a tube, so I don't see how it cannot be accessible.

Yes, the wire itself must be accessible (even if with a bit of effort) but my point is that, for reasons I mentioned, there might not be a terminal provided for connection to it. However, if, as you are implying, one is prepared to 'break into' that wire, if necessary, then there is every chance that whatever is doing the switching would be able to cope with a further one or two low-powered LED loads.

Kind Regards, John

 

[ban-all-sheds]

He could always ask Newlec....