Fault on lighting circuit?

[jason_exact]

Hi people,

Changed a consumer unit today to a 17th ed split load wylex. Switched on and all was fine for 10 mins then, rcd tripped by the downstairs lights, switched on again and worked for another 10 mins. Meantime i plugged in several different appliance fridge freezer, hoover, toaster etc and each time i did on the same ring it tripped the rcd.

I then took out the downstairs lighting circuit and this meant the ring which was tripping was fine. I then tried connecting lighting circuit again but it was tripping instantly this time.

I have removed all switches and nothing visible loose or nipped.

Can i have some advice on fault finding the lighting circuit? Please keep it step by step and simple im new to fault finding!

Any ideas how the ring is linked to the appliances being plugged in and the lighting circuit?

advice welcome, please help guys!

Cheers......

 

[acat]

Have you got a strip light on the circuit.


Chris

 

[jason_exact]

No just 2 light fittings with 3 lamps on in the lounge and 1 ceiling rose with pendant in hallway,

 

[m4tty]

not a borrowed neutral is it?

 

[jason_exact]

How do i know if its a borrowed neutral? How do i test if it is or not?

 

[Spudnik]

The only way you will find if it is a B.N. is to IR test between all the neutral conductors.

 

[Sintra]

Have you 2 lighting circuits split between the 2 rcd's?

If so check landing light as the neutral for this could be taken from upstairs lighting circuit with the switched line from the downstairs circuit.

 

[Deleted member 9648]

First step would be to carry out an insulation resistance test on all circuits connected to the cu....you should have done this before energising......otherwise i'ts guesswork.

 

[Spudnik]

Yes indeed.

I assumed this was carried out already.

 

[jason_exact]

I have got lighting on both rcds. i thought it might be the case of the neutral from upstairs so i put the donwstairs lighting in with the other rcd to check and it still tripped.

Not carried out IR yet, sorry!

So IR first and then go from there?

 

[Sintra]

To check you need to make sure both lighting circuit lives & neutrals are connected to the same RCD. If you do this and it still trips then you need to get that IR testing done.

 

[super_stuey]

You should be doing IR testing NEWAY!!!!

dead tests.........energise........live tests.......done.

 

[jason_exact]

cheers i appreciate tests should have been done before energise but in this case it was to be done once energised as i was working a couple of hours away. cheers for the advice about IR before i assure all tests will be carried out just ion this case as i sadi in the wrong order.

More advice on main issue welcome please!

 

[chris gray]

have you ever used a split board before?

 

[jason_exact]

Yes for the last couple of years