2 way lighting

[shedbang]

Hi

Went to replace a pull cord with a standard light switch in a house we've bought. It's part of a 2-way arrangement and I was surprised to see that when I opened it up, the wiring was yellow to common, red to L1, and blue to L2 (obviously old colours).

So I opened up the other switch on the 2-way and was doubly surprised to find the same arrangement with no feed from the ceiling rose (ie both switches only had 3-core + earth in them).

Looking at the ceiling rose, there is a standard switched live (ie red and black T&E with black sleeved red).

So 2 questions:- there must be a JB somewhere - behind the plaster board I guess (there is a fair sized void there and the house was re-wired in the mid-90's) - what would be the connections in there? I'm also surprised by the use of yellow for common. Isn't this supposed to be red? Nothing in the switches is sleeved...

Obviously I shall just replace the switch along the same lines, but is there anything that I should be worried about here?

JB

 

[sparkwright]

There will be a junction box or junction boxes.

It could be anywhere but above the ceiling is usual.

It should be accessible, but quite often they are not.

I wouldn't worry too much, there are 1000s and 1000s and 1000s unaccessible junction boxes.

EDITED FOR SPELLING.

 

[sparkwright]

Nothing wrong with using yellow as the common. There are no set rules.

Red is slightly more usual.

(Very rare to see blue as the common...)

 

[ricicle]

The yellow and blue cores should have been identified red. There could be a JB somewhere, or have you checked that both 3 cores might go to the light (bit of a squeeze but it is possible if crimps were used to join strappers)

EDIT: Too slow and just seen the bit about the ceiling rose

 

[Electrifying]

.........there must be a JB somewhere - what would be the connections in there?

If it's not done at the ceiling rose, then there will be a junction box somewhere.
In the JB the 'live feed' will be connected to the 'Red' conductor and the 'switch live' will be connected to the 'Blue' conductor. (or vice versa, it doesn't matter) - the yellow conductor will carry straight through between the switches.

As said by others, 'Blue' and 'Yellow' should be sleeved 'red' in both switches and the JB - as should the 'black' conductor.......all are 'live' conductors in this arrangement.

 

[Electrifying]

.........there must be a JB somewhere - what would be the connections in there?

If it's not done at the ceiling rose, then there will be a junction box somewhere.
In the JB the 'live feed' will be connected to the 'Red' conductor and the 'switch live' will be connected to the 'Blue' conductor. (or vice versa, it doesn't matter) - the yellow conductor will carry straight through between the switches.

As said by others, 'Blue' and 'Yellow' should be sleeved 'red' in both switches and the JB - as should the 'black' conductor.......all are 'live' conductors in this arrangement.

Of course, I could be totally wrong and (in the JB), it might just be the 'yellow' conductor is split - with one end connected to the 'red' of the T&E and the other end connected to the 'black'

Either method works - more likely to be the first, me thinks.