RCD trip across board

[Mark Playford]

I am a relatively newly qualified electrician and have completed a re-wire but come across a problem i dont understand.

I have a dual board with a lighting and a power circuit on each side. On the right side the power and lighting is entirely stable, but whenever a load is applied to the sockets it trips the left side RCD.

When i put load on the left side power circuit or put on more then three LED lights it trips the left RCD.

I have tested all the cables and cannot find any cause (such as wrong wiring or nails through wires) for the tripping.

Any ideas please, please?

 

[westward10]

Crossed neutrals in the board, check the neutral conductors are in the correct neutral bars.

 

[Pete999]

What he said ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

 

[Octopus]

or 2 faults .......... one on each side.......

On a rewire its probably the easiest fault finding you can do .......you know where all the cables run, where all the points are .....

 

[Pete999]

Probably something to do with the two way lighting circuit on the landing/hall lighting connections

 

[Pete999]

I am a relatively newly qualified electrician and have completed a re-wire but come across a problem i dont understand.

I have a dual board with a lighting and a power circuit on each side. On the right side the power and lighting is entirely stable, but whenever a load is applied to the sockets it trips the left side RCD.

When i put load on the left side power circuit or put on more then three LED lights it trips the left RCD.

I have tested all the cables and cannot find any cause (such as wrong wiring or nails through wires) for the tripping.

Any ideas please, please?

Where are you in the UK

 

[Strima]

Either crossed neutrals in the board or two separate faults.

Crossed neutrals has caught me out before because I assumed BG had wired the DB properly...

 

[Octopus]

Where are you in the UK

Birchington? Broadstairs?

 

[Midwest]

Don't go wibble, and proceed in a logical manner, if need be go back to the beginning (testing). Keep thinking and take on the ideas the chaps have given. Think of it as a learning exercise. Something to store for the future. Every day is a learning day

 

[Mark Playford]

Thanks everyone.

The part that i thought i had included but now realise i didnt is that everything was working fine until about 1030 on tuesday. The RCD tripped and i have done everything i can think of short of starting the board again.

The thought that it could be a 2-way switching problem is interesting and not one i had thought of. The are two 2-way switches - hallways up and down stairs - that are in 2g2w switches so maybe, just maybe the 2-way cables are 'crossed' and one of the other guys switched the switch.

Otherwise what would cause a borrowed neutral that just appears?

 

[Octopus]

If you can track a working site back to a time when it did work, are you aware of anything that changed ? its been very wet around here so could water be the issue?

Done any DIY? Hung any pictures?

As for the 2 way switching, your dead tests should have shown this as an issue.

 

[Lucien Nunes]

Sounds like an N-E fault on one of the circuits on the left RCD. Load on either circuit could cause it to trip. If your IR is good on both circuits, the fault could be within an appliance that has been plugged in to the left hand socket circuit - which might explain it having been OK at first.

 

[Strima]

Dead test results all good?

IR good in all switch positions?

 

[Mark Playford]

All tests good - it did rain heavy before the first instance. Have i been that daft - not aware of any leaking, but it could be....

 

[Des 56]

A load on one half tripping the Rcd on the other half will have resulted from a interconnection between the 2 sides
With earth faults ruled out,it may be either the usual consumer unit cross over cock up or a external circuit cross over cock up

Because it didn't happen,then did happen,the chances are its a circuit cock up rather than a consumer unit cock up

The fault seems to me to have been switched into existence by actions,check those 2 ways again