Installing PIR - 3-core to 2-core advice?

[pbaumann]

Hi,

I've spent this afternoon scouring the forums here to work out what the best thing to do would be, but I'm still a little unsure.

I've purchased a new 30W PIR Light for above the garage (https://smile.amazon.co.uk/gp/product/B079FKHYJ8/). There was previously a halogen motion sensor light on there, which was constantly triggering irrespective of how I pointed the sensor or the sensitivity I set it to, and was also using up rather a lot of electricity in doing so, hence the replacement.

The setup is as follows:
1. Existing light switch in garage which, when on, used to send power to the old light so that it was only triggered during motion. When off, motion didn't trigger the light, it stayed off.
2. There is existing wiring from the light switch to a junction box, ready to connect to the PIR Light. This cable has 3 cores and an earth wire. In the switch box on the wall, the black wire has brown wrapped around it, the grey/white wire has blue at the end. There is also a copper one which has green/yellow wrapping (presumably earth?) and a brown cable. So, Black (with brown wrapping at the switch), Grey (with blue at the switch), Brown, and Green/Yellow.
3. I've bought this junction box from Screwfix - https://www.screwfix.com/p/debox-in-line-connector-box/8692h
4. The lamp wiring is only 2 cores - Brown (L), Blue (N) and Yellow-Green (Earth).

I stupidly forgot to note how the old one was wired, although I'm not sure how useful it would have been as the light itself seems to have more complicated wiring anyway (looked similar to this, found on the forum https://www.diynot.com/diy/attachments/20170203_205952-jpg.113496/).

Does anyone have any advice as to which wires should be linked to one another in the junction box? There are 4 cables to connect from the switch, but obviously only 3 to the light so I'm not sure which should be dead-ended, as it were, if any.

Thanks very much for any advice you can offer! I've made sure to turn off both the light switch and the RCD switch before unplugging it all.

 

[ktuludays]

From what you've written:

So, Black (with brown wrapping at the switch), probably switched live,.is it connected to L1 terminal?


Grey (with blue at the switch) - neutral

Brown - permanent live.from supply side? Wired into common?

and Green/Yellow. - earth

A pic of wiring at switch would.be needed to confirm.

 

[Taylortwocities]

It seems that the old light supported an over-ride feature that needed a switched live from the switch. the new light doesn’t have this feature- although it may have a ‘pulse’ override facility. See the instructions!

The grey with the blue sleeve is the neutral.
the brown is the permanent live.
The black with brown sleeve will be the switched live.

We need to see the wiring to the switch, or you can determine which is which if you have a voltmeter.

PS. Where will you locate the junction box? The one in your link is not suitable for use outdoors!

 

[pbaumann]

Thanks for your responses. I've attached a couple of photos of the socket below. I do have a multimeter I borrowed from someone - although I've not used one before so need to look online as to how exactly I should check which cable is which and what settings to use on the multimeter. The socket on the right nearest the camera (or the left hand switch if you're looking at it from the front) is the one the old light used. The other socket is for the main light in the garage.

It seems that the old light supported an over-ride feature that needed a switched live from the switch. the new light doesn’t have this feature- although it may have a ‘pulse’ override facility. See the instructions!

Unfortunately the instructions don't specify anything other than the basic connecting of the three wires - nothing about potential over-rides.

PS. Where will you locate the junction box? The one in your link is not suitable for use outdoors!

Yep, it's inside the garage where it's dry.

 

[pbaumann]

These are my options at the other end (connection to light). I'm aware it looks messy at the minute, and obviously won't be hanging down once it's all finished. That was just for the pic!

 

[Taylortwocities]

Ok. So. Grey(with blue sleeve) to neutral on the light.
Black with brown sleeve to live on the light. This is the switched live so you can disable the light by turning off one of the switches.
earth to earth.
Terminate the brown conductor in a spare terminal in the JB. It doesn’t go anywhere.

re the JB. That’s a mess. The cable sheath should be inside the box. The clamps at each end screw down on the outer sheath, not the inner cores.

Nice to know you have a test meter. Maybe (new year resolution) a good idea to spend some time learning how to use it. Otherwise it’s of no practical use.