Today's curiosity:
Looking to wire for staircase LEDs. As a reminder, this house has live/earth looped at the switch and neutral looped at the light fittings. Downstairs hallway switch controls the downstairs hallway light (1-way) and upstairs landing light (2-way). Looking behind the switch I have managed to track most but two things have me confused:
1) I note L2 (and L1) is wired in for the downstairs switch (ie 2-way). Now I've searched high and low and there is no second switch but given the house had a major extension, it's possible it was originally a 2-way. Would it also be possible that when the potential second switch was removed, the sparky just connected the L1 and L2 wires together and buried it somewhere so that effectively it has reverted to a one way switch (but would require me to keep the L2 and L1 wired in?
2) A cable is coming into the downstairs switch with two live and one earth. I get one live and earth continues the loop but have no idea what the intention would be for the second live (both connected to COM)
All quite standard on the upstairs landing switch, also a combination of 2-way (landing light) and 1-way (loft light) with landing light fed off the downstairs radial and the loft from the upstairs as per below
A final point on this is with regards to neutral. I know aside from issues with regards to interference with this running independently, there is risk that the upstairs light is live from the downstairs circuit and neutral from the upstairs. Is there a multimeter test I can carry out to determine this?
With regards to what I am actually trying to achieve, I will be changing the downstairs 2-gang switch to a 3-gang and introducing a new switch at the top of the stairs i.e. the stair lights can be controlled from either the top or bottom. From a live/earth perspective it's relatively straight forward. From a neutral perspective, there is no obvious neutral near the top stair switch, can I take a feed from any neutral point on the ground floor circuit? (will keep on ground floor circuit to marry up with landing light treated the same)
Apologies for long post!