New House Wiring Configuration Ask questions and find answers to many subjects relating to electrics and electrical work

[troubled]

Just tried introducing a dimmer switch to a new house only to find that both the colour coding and number of insulated wires contained in the main loom is something I have never seen before. The ring main loom consists of 3 sheathed wires 'Grey, Black & Brown' and an unsheathed earth cable. What makes the whole wiring system even more odd is that twin wires to the ceiling light are both brown.

Could someone explain how this lot is connected back to the junction box please

[pyro_mania]

https://www.diydoctor.org.uk/projects/wirecolours.htm

[ericmark]

Brown = Red
Black = Yellow
Gray = Blue
Blue = Black
To be correct the wire from light to switch should be two browns but often you get brown and blue with brown sleeve on blue. Which is how the projects page shows it.
From colours you must have two way switching so the dimmer must also be two way