RCD keeps tripping the breakers

[Doncornelius]

Hey guys just joined the forum because I'm having this issue.
Been a few days now and my RCD trips and 2 breakers stop it from turning it on again.
Only when I leave these 2 breakers off, does the rcd goes back on.
The 2 breakers are for the kitchen. So all sockets incl fridge, washing machine, cooker and other usual kitchen appliances.
I unplugged all these appliances and still rcd trips when the 2 cbs are switched on.
So i had to use an extension cable to plug these appliances from another socket to keep them on.
I've opened up the consumer unit to check if these wires are screwed in properly. Seem fine.
I then unscrewed all the sockets in kitchen to check wires for any damage, water ingress and loose. They seem fine.

I then reopened the cons. Unit and took the 2 live wires and put them in another set of cb. But the rcd still trips.



Can anyone help?

Thanks

 

[ericmark]

You need a meter like this,

to find the fault, normally cheaper to get an electrician to do the job.

 

[Murdochcat]

Are you 100% sure that you have isolated all appliances connected to these 2 circuits?

 

[blup]

Check again the wiring in each socket for loose or touching wires, failing that get a sparky in who will do an IR test and check the condition of the breakers.

 

[FrodoOne]

Been a few days now and my RCD trips and 2 breakers stop it from turning it on again.
Only when I leave these 2 breakers off, does the rcd goes back on.

It is "Unusual" that the circuit from two MCBs would have the same/similar "Earth Leakage" fault, causing the "common" RCD to operate.
(However, this is another example of why it is better to have RCBOs for each circuit than having RCDs in "common".)

The 2 breakers are for the kitchen. So all sockets incl fridge, washing machine, cooker and other usual kitchen appliances.
I unplugged all these appliances and still rcd trips when the 2 cbs are switched on.

There is a commonality there, in that "The 2 breakers are for the kitchen"

The next question are:-

Are you 100% sure that you have isolated all appliances connected to these 2 circuits?

and
are there any noticeably "damp" areas in this kitchen?

 

[Taylortwocities]

I then reopened the cons. Unit and took the 2 live wires and put them in another set of cb. But the rcd still trips.

Ah, but the RCD monitors an earth fault on the line AND the neutral sides of the circuit. To isolate the circuit you will need to remove the line (or turn off the MCB) and also remove the neutral connections.

Common problems are anywhere that water and electricity can meet. First checks are any external sockets, lights etc. then boiler valves, pumps etc (if boiler is on one of those circuits then make sure you have completely isolated the boiler. There should be a single double pole switch for this purpose (or a plug).

 

[Doncornelius]

Many thanks for the responses yes, it can't just be a coincidence that both of the wires from the breakers are from the same area as in the kitchen.

No Damp Areas

I'm sure all the sockets associated with these two wires I had unplugged and checked for looseness and dampness.

When the 2 breakers are off there's nothing else in the property that is off ie I'm sure I have unplugged and checked every socket associated with these two breakers.

What I did fail to mention however that the RCD did used to trip intermittently however once turning off all the breakers and resetting the RCD it would stay back on however now is just gotten worse.

 

[Doncornelius]

Ah, but the RCD monitors an earth fault on the line AND the neutral sides of the circuit. To isolate the circuit you will need to remove the line (or turn off the MCB) and also remove the neutral connections.

Common problems are anywhere that water and electricity can meet. First checks are any external sockets, lights etc. then boiler valves, pumps etc (if boiler is on one of those circuits then make sure you have completely isolated the boiler. There should be a single double pole switch for this purpose (or a plug).

Sorry I should have said I did remove the twin and earth from both breakers and put them in different cb as well as attached the neutral and earth into different terminals but still same issue.

 

[ericmark]

It is "Unusual" that the circuit from two MCBs would have the same/similar "Earth Leakage" fault, causing the "common" RCD to operate.
(However, this is another example of why it is better to have RCBOs for each circuit than having RCDs in "common".)

This normally means a neutral is in the wrong neutral block, but this can't happen without someone moving wires around.

Sorry I should have said I did remove the twin and earth from both breakers and put them in different cb as well as attached the neutral and earth into different terminals but still same issue.

However, it seems wires have been moved.

I did have to with this house correct which neutral was used in a 4 gang light switch. I am trying to think how to instruct an ordinary person how to correct, but it seems more likely in the attempt they would make it worse.

So to basic way an RCD works, it measures current out, and current back, and if the same or within 15 mA of each other, it will remain connected, at some point between 15 mA and 30 mA difference it will trip. It does not measure current to earth, it just assumes if out does not equal in current then it must be going to earth, however it could also be down a different neutral circuit.

A picture of the inside of the consumer unit may help, but otherwise the safest option is to call an electrician, and be honest about what you have done. We look for likely cause, and for a wire to swap terminal on its own, is unlikely so unless warned we would not look for that.

 

[SUNRAY]

The fault you are describing is classic symptoms of failed mains filters in whie goods such as dishwashers, washing machines, tumbledriers.
Have they definitely been unplugged/isolated

Following what has already been written I agree

A picture of the inside of the consumer unit may help, but

in reality I suspect we can't help further at a distance and

the safest option is to call an electrician, and be honest about what you have done. We look for likely cause, and for a wire to swap terminal on its own, is unlikely so unless warned we would not look for that.

The electrician will genuinely be delighted to be told the truth, there is nothing worse than trying to chase a fault thinking it used to work as currently wired.

 

[ericmark]

Remember, switching off is often not good enough. There are double pole switches on some FCU and Sockets, but not all, so the items need unplugging. Neutral to earth can trip an RCD, same as line to earth, but switches often don't disconnect neutrals. And posting same question on multi forums does not really help.