two way lighting

[18leonh]

I have a head scratcher with this. My girlfriend lost her downstairs lighting. I am trying to sort it. Meggered the cct with lamps out & light switches off from the CU connection which were removed from cu. It seemed there was a short between phase, neutral & earth. Have checked all fittings for loose connections now and removed all outside lights from the cct. The fuse wire blows immediately. Looking further I decided to check out the recently replaced two way switch with parallel lighting for upstairs and downstairs landing and hallway. The 2 two way switches have 3 core & earth but are joined into the circuit at a JB, not at one switch as I expected. The JB also has the supply in and out & the power to the downstairs light. The downstairs fitting is then connected straight to the upstairs with 2 core and earth. The switches are confusing me with 3cores. Reds to common on both, yellow to L1 & blue to L2 on one switch opposite on the other. In the JB yellows together, blues together, 1 red to supply and one to light fitting supply red. All blacks in the JB together. Sorry if this confusing in words, trying to get the photo labelled so I can post it. Any help would be incredibly well recieved.

 

[jj4091]

If the lighting cct., is wired with junction boxes rather than looping in & out of the ceiling roses & the fuse blows without switching on any lights then it would suggest it is one of the cables that supply each cct. that has a short & you will need to disconnect them for one room at a time until the short disappears.

 

[ColJack]

this is just 2 plate wiring done a little different..

you have 2 strappers, the yellow and blue, with a live into the common of one switch, and the light into the common of the other..

if it keeps blowing the fuse then i would suggest that one of the "feeds" into the JB is in fact a switch wire from somewhere.. so you short live to neutral with a switch on..

seperate out the "feeds" into individual chock blocks and try again..