Replacing a 2 gang 2 way with a 3 gang switch

[chris99t]

Hi I have installed an outside light next to my front door. I have fed the cable to an existing light switch. This switch operates a light at the bottom of the stairs with one switch and the light at the top of the stairs with the other. There is a similar switch at the top of the stairs.

I have purchased a 3 gang(switch) switch plate and need to replace the existing 2 gang(switch) plate. Its the wiring I can't get my head round.

The old switch had two blocks on the back. Each has an L1 & L2 at the bottom and a 1 & 2 at the top. The new switch plate has one single block split into three sections each of which has L1 & L2 at the top and COMMON at the bottom.

The mains cable has Red, Black and Earth, the two other existing cables have Red, Blue Yellow and Earth. My new cable has Blue, Brown and Earth.

Complicated I know. maybe a diagram would help me! the ones with the switch was poor.



Chris

[chris99t]

I have wired the lights and they are all functioning fine. I just need to wire the outside light into the switch. I don't have a live feed to the light. I have run a 2 core & earth to the switch from the light. Can I put a bridge in from the main live feed connection for the interior lights?

[sparx]

short answer yes from downstairs light, say in hall. Neutral to new light, live+switch live in spare loop in term at outside light, switch live back to L at new light. mark both ends of switch cable with brown sleeving/tape on blue core to show it's not N but sw/line.
see 'project-electrical-lighting' for colour drawing
regards Sparx