New outside light - existing wiring has yellow wire (three-p

[BradThunder]

I am replacing an outside security light fitted with a PIR with pretty much the same fitting, only new and after disconnecting the old one, I found four wires, red, blue, green/yellow and a plain yellow, which I believe indicates a three-phase supply...? Not being terribly knowledgeable about that set up, can someone tell me how to wire the new fitting which is obviously asking for the newer live brown, blue neutral and the green/yellow earth? I've seen a wiring diagram that has the yellow to live and the red to the spare, is that correct? Thanks in advance!

 

[EFLImpudence]

I found four wires, red, blue, green/yellow and a plain yellow, which I believe indicates a three-phase supply...?

No. Just coloured wires.

newer live brown, blue neutral and the green/yellow earth? I've seen a wiring diagram that has the yellow to live and the red to the spare, is that correct? Thanks in advance!

Just connect the same wires as were connected before -

G/Y to earth
Blue to Neutral Blue
Either Red or Yellow to Brown (whichever it was before)
Put the other wire in a connector block and leave separate.

If you are not certain about the Red or Yellow look in the switch and tell us what wires are in there.

 

[BradThunder]

Thanks EFLImpudence, I followed it back and had a look in the junction box, turns out the yellow wire was not connected to anything! Working beautifully!

 

[SimonH2]

Just for completeness if someone comes along later to look at this.

On some installations the extra wire will be connected. There'll be a live and neutral, plus a switched live - with those colours it would typically be red for live, blue for neutral, and yellow for switched live. This allows a switch (eg inside the house) to override the PIR and turn the light on continuously.