Marking on 2-way light switch

[nbr]

"Does not matter if other wire goes to 1 or 2, although most would as default put it in 1." unless using Mk switches when putting it in 1 will mean the light on with switch "up" and scolmore is the other way round DAMHIKT

The one in my original 2nd pic (with L, 1 and 2) is MK. I wired it up with L being com and 1 being L1 and the switch with turn light on when pressign the switch down.

I have now a complication in the stairs where one 2 way + one intermediate are upstairs and one 2 way is downstairs, all controlling one light on the stairs. The two switches upstairs work ok, as soon as I wire up the switch downstairs (2 way, with L being com, 1 being L1 of the old switch and 2 being L2 of the old switch) the RCA for the downstairs lighting trips... And I believe I kept the same connections and wiring as in the old 3 sockets previously installed... Will ponder...

 

[robinbanks]

Do you have pics of the backs of all the old switches?

 

[nbr]

Do you have pics of the backs of all the old switches?

Here is a pic of the old intermediate switch and a pic of one of the old 2 way switches (the 2nd pic has the 2 way switch wired up as a 1 way but that is a light switch in another location - it gives an example of the old 2 way switch I originally had).

The new intermediate switch has L3 and L4 for the bottom connections, instead of L1 and L2, and I assumed L3 to be a 2nd L1 and L4 being a 2nd L2.

The new intermediate switch works well together with the upstairs new 2-way switch. It is the downstairs 2-way switch that is causing the problem. I might try and invert L1 and L2 in the downstairs switch. Or just connect L / COM in the downstairs switch and see if that alone causes an issue (wouldn't have thought so).