rcd tripping wrong wiring ?

[darr]

hi all just had new rcd board fitted replacing old fuse wire type ,getting rcds tripping when switching dining room lights on or upstairs landing light on ie both on same twin switch socket ,befor new fuse board fuses never blew although landing light could only be turned on or off from upstairs ,although downstairs switch had to be in right position but dining room lights switch off or on fine,thanks for any advice ,hopefully got pic of wiring to switch

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• darr
• 3 Apr 2011
• 1

 

[ricicle]

Who carried out the board change ?

If you can post a copy of the test results on here we might be able to help.

 

[darr]

was a mate did it ,hes a real electritian but cant get back to me as on his hols ,he reckons the switched lives wrong way round or something like that

 

[1john]

If thats the case then you need to get a sparky that knows whats wrong in, it is very simple and very common but can be awkward to rectify. Bloody sparkys always going on holiday after a board change and not certifying the work.

 

[starspark]

sounds like a borrowed neutral all day long. thatsonly shown up now you have fitted rcds!!

 

[darr]

Cheers all ,is a borrowed neutral easy to rectify ?

 

[Buzx1313]

could be an earth neutral fault ..

 

[Spark123]

Electrician on holiday, left the country or abducted by aliens??
It is an easy enough job to do for a spark. It may involve some destruction of decor if it is a shared neutral.
On the other hand, in that switch can you see the cables? Is the red which belongs to the blue/yellow in the same switch as the blue/yellow?
Can you post a pic of the upstairs switch?

 

[darr]

heres a few pics ov upstairs switch both same switch different views

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• darr
• 3 Apr 2011
• 1

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• darr
• 3 Apr 2011
• 1

 

[Spark123]

Firstly I think that the blue and yellows are in the wrong positions downstairs, they ought to be in L1 and L2 (doesn't matter which way around at the moment - wrong way around will just make the switch work upside down).
The red from the same cable as the yellow and blue needs to be in the COM terminal.

The red and black in the cable from the lounge light to the COM and L1 terminals for the other switch.

As a side note, all non red switch wires ought to have red sleeve on them to signify they are all line conductors.

 

[darr]

Thanks sparks ill try it out as soon as i get power off and let u know the outcome

 

[sparkwright]

Do you have two or more lighting circuits?
Send a picture of your consumer unit if possible.

 

[darr]

heres pic of fuse board showing the 5 mcbs used rest of board not used

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• darr
• 3 Apr 2011
• 1

 

[ajrobb]

As said before, a 'borrowed neutral' fault means that line and neutral come from different circuits. In you case, the different circuits might be on different RCDs. This can be a hazard as it is not possible to isolate the circuits at the CU. The lights at the top and bottom of the stairs ought to be on different RCDs. As you haven't got two sets of wires going to either 2-way switch, there is probably a junction box somewhere in the loft.

 

[starspark]

well you could put both lighting circuits on the same rcd which would cure the tripping but this is not ideal. failing that you will have to search out your wiring and figure out wghat goes where. as said before theres probably a junction box somewhere.