RCD's Again.. And my head hurts!

[cardinal]

Hello chaps. I hope one of you scholars can help me with this.

Part re-wire to 2 storey flat. I have installed 8 lv downlights to down stairs kitchen, and 10 to up stairs lounge.. Now when i attempt to turn them on the RCD is tripping. Now, both 6A lighting circuits, split up and down are on the non RCD side of a split load board. And using my some what limited fault finding expertise i cant resolve it. Pretty sure all is ok at the board so im now at a loss. My testing is raw to say the least, so i was just hoping some one out there could point me in the right direction on how to solve it.

Since getting on here, i have read a bit about borrowed neutral? is that a possibility?

Thanks in advance.

 

[oldtimer]

You say you have put these light circuits on the non RCD side of the board but it sounds like you have connected the neutrals into the RCD side why.

Well before you started the RCD was ok but if you have put the neutrals on to the RCD neutral bar then you have caused an imbalance hence the trip How to check is switch the new circuits off reset the RCD then switch each circuit on one at a time if the RCD trips then thats your man

 

[telectrix]

have you done any mods. in the CU? if not, try isolating each lighting cct. in turn. if one cct causes trip and the other doesn't, then you've narrowed it down. borrowed neutral is a possibility.

 

[cardinal]

The neutrals are on the non RCD side. With every other circuit off in the board, RCD on, each lighting circuit will trip it in turn. But what i have noticed is, if you leave each bank of DL's off, it will hold in. Flip switch for the DL's, then it trips. I thought there might be an exisiting fault maybe(level ofleakage to earth) and the DL's just take it over?

 

[telectrix]

can't see how if you have put then on the non rcd side. does sound like a neutral problem. what's your location?

 

[Jimmy Boy]

Hello chaps. I hope one of you scholars can help me with this.

Part re-wire to 2 storey flat. I have installed 8 lv downlights to down stairs kitchen, and 10 to up stairs lounge.. Now when i attempt to turn them on the RCD is tripping. Now, both 6A lighting circuits, split up and down are on the non RCD side of a split load board. And using my some what limited fault finding expertise i cant resolve it. Pretty sure all is ok at the board so im now at a loss. My testing is raw to say the least, so i was just hoping some one out there could point me in the right direction on how to solve it.

Since getting on here, i have read a bit about borrowed neutral? is that a possibility?

Thanks in advance.

Assuming you came off two existing circuits ? Were the circuits in question OK before your additions ? In any event assuming you haven't done something silly like swapping Neutrals on the board, pull the L and N from each circuit to determine which one holds and which one trips the RCD do you have test equipment that can find a fault ?

ATB S

 

[oldtimer]

The neutrals are on the non RCD side. With every other circuit off in the board, RCD on, each lighting circuit will trip it in turn. But what i have noticed is, if you leave each bank of DL's off, it will hold in. Flip switch for the DL's, then it trips. I thought there might be an exisiting fault maybe(level ofleakage to earth) and the DL's just take it over?

Check again as I said if you switch the circuits off and the RCD operates ok and then you switch them on and it trips then you are connected to the RCD neutral bar. Also trace the neutral leaving the RCD to the neutral bar and check if your 2 light circuits are wired on to it

 

[cardinal]

Defo nothing wrong at board. I have done IR test on both circuits, nothing showed up. But like i said before my testing isnt the best yet and i'll gladly take advice on redoing it if thats what required. Oh, and im in Surrey.

 

[Deleted member 9648]

Hello chaps. I hope one of you scholars can help me with this.

Part re-wire to 2 storey flat. I have installed 8 lv downlights to down stairs kitchen, and 10 to up stairs lounge.. Now when i attempt to turn them on the RCD is tripping. Now, both 6A lighting circuits, split up and down are on the non RCD side of a split load board. And using my some what limited fault finding expertise i cant resolve it. Pretty sure all is ok at the board so im now at a loss. My testing is raw to say the least, so i was just hoping some one out there could point me in the right direction on how to solve it.

Since getting on here, i have read a bit about borrowed neutral? is that a possibility?

Thanks in advance.

With a statement like the one above I'd be a little concerned whether you should be attempting rewiring work......Have you installed totally new circuits and connected them to the non rcd side after carrying out IR tests?....or have you extended existing circuits?...
If the former and IR tests are satisfactory you must have mixed up the neutrals in the DB...as if both lives and neutrals are connected correctly on the non rcd side they cant trip the rcd.
If the latter you either have a borrowed neutral from the RCd side or incorrectly connected in the DB.

 

[nickblake]

It could well be a shared / borrowed neutral ,switch board off at isolator and put a test between the 2 neutral bars you shouldnt get a reading if you do then you have a borrowed neutral

 

[oldtimer]

Cardinal take a photo of the board with the cover off and post it here

 

[Jimmy Boy]

Switching off an RCBO or an MCB will only isolate the line conductor, and RCD will be a double pole hence the hint at pulling the N's.
IR test did you use method 1 or method 2 ? You don't want to be banging 500V up trannys

 

[spanner]

Hey there, could you advise us as here too seems to be a similarity ere with me2.I,m up to a polarity test tomorrow and forgot to mention that the kitchen has a smoke alarm fitted and this was connected to the wire s in the kitchen. I've checked them for live and they're all flat!!
Would this have been a cause as to why after I'd finished doing the GU10s it tripped the switch in the consumer unit????
Large help here..!
Thanks.

 

[spanner]

Keeping my fingers crossed I help you guys with a plumbindg problem senario!!!

 

[cardinal]

Im almost positive everything is as it should be at the board. All i have done is strip out everything back to the initial feeds from the board and wire on from there. Think ill have to bite the bullet and get some cavalry in on Monday. Im confident enough in my installation work, its just ive recently moved on from a company where some one else did the majority of the testing and im still finding my feet a bit, especially with fault finding obviously.