3 gang switch question

[AS]

i have a 3 gang switch.
1st gang is 1 way
2nd gang is 2 way
3rd gang is 1 way

When I opened it up I expected to find
1 of 3 core switch cable and 2 of 2 core switch cable

each gang has 4 terminals two labelled 1 and two labelled 2

However what i found is 1 of 2 core cable and 1 of 3 core cable wired as follows:

N from 2 core going to 1 on 1st gang
L from 2 core going to 1 on 3rd gang

yellow from 3 core going to 1 on 2nd gang
blue from 3 core going to 2 on 2nd gang
L from 3 core going to the other 1 terminal on 1st gang and from this
2 added loops of Live into the free 1 terminals on gangs 2nd and 3rd.

What is this, is it safe/common and more importantly how do I wire on a new replacement 3 gang switch using this method?

 

[Paul_C]

It sounds as though you have a triple intermediate (4-way) switch bank Such switches would normally be used where you want to control a light from three or more different locations, but they can also be wired for regular 1/2-way operation.

Assuming that all the lights work properly and independently of each other, the red on the 3-core must be bringing power into the switch bank. The yellow and blue on switch #2 are then the travelers which run to the other switch of the 2-way arrangement. The 2-core cable appears to have been used as the switch returns for the other two lights: Red for #3, black for #1.

To replace with a triple-gang 2-way unit you would need to connect as follows:

3-core red to the common of all three switches.
3-core yellow and blue to L1 and L2 of switch #2.
2-core black to L1 of switch #1.
2-core red to L1 of switch #3.

If it makes the wiring physically easier, you can interchange the COM and L1 connections on switches #1 and #3 as they're only being used as 1-way.

 

[securespark]

Just satisfy my curiosity as to the brand of the old 3 gang intermediate switch: as far as I'm aware, only Scolmore (Click) give you the ability to fit three int. switch modules into a one gang plate.

 

[plugwash]

mmm 12 connections in a 1 gang box not counting the chock block you usually have with intermediates or the earths.

do you enjoy self tourture?