Outside light wiring

[Pick]

Hi,

I have jut moved into a new build house and have changed the ceiling light fittings by connecting the blue, brown and green/yellow from my ceiling to the new light fitting.

I want to connect an external light to the wiring on the outside wall. On my light I have a chocolate box for live, earth and neutral but coming out if the wall I have brown (live), green/yello (earth) and a black and grey wire.

Which three wall wires do I connect to my light and what do I do with the spare fourth??

Thanks

 

[Taylortwocities]

You will have to find where those wires are fed from. Possibly from a switch that controls the light? You will also need a test meter.

It may be wired up for a PIR light so you may have neutral, live and switched live plus an earth.