Main incoming rcd tripping on any circuit

[farmerboy]

My main incoming rcd is tripping out as soon as any load on any circuit. Have pulled each circuit out of the board live and neutral in turn but failed to isolate it to any specific circuit, is this likely to be the rcd at fault?

 

[UNG]

Removing and replacing the circuits one by one would suggest that more than one circuit has a fault on it, testing each circuit would be the way forward, it would probably be more time and cost effective to get an electrician in

It is always possible that the RCD is faulty and this can be confirmed by testing with an MFT or RCD specific test instrument

 

[stevethesparks]

More likely to be a neutral to earth fault. I note you are DIY, might want to consider calling a sparky in.

 

[snowhead]

When you say taking the Neutrals out 1 at a time does that include taking both neutrals out for any ring circuit, if there are any.?
And it's possible that the Ring neutrals could be mixed up in the neutral bar.

 

[farmerboy]

Removing and replacing the circuits one by one would suggest that more than one circuit has a fault on it, testing each circuit would be the way forward, it would probably be more time and cost effective to get an electrician in

It is always possible that the RCD is faulty and this can be confirmed by testing with an MFT or RCD specific test instrument

Thanks, I have removed both ring mains and the cooker still trips and lots of combinations in between so my money is on the rcd a fairly quick and easy swap so think I'll start there..... It's a fairly small system 2 ring mains, 1 lighting circuit, cooker and shower. Have pulled them all out and had each one on its own still trip so unless every circuit has a fault it must be rcd surely

 

[telectrix]

N-E fault. as soon as any circuit pulls current it trips. job for a competent sparks or youse'll need a syrup to replace all the hair you pull out.

 

[farmerboy]

N-E fault. as soon as any circuit pulls current it trips. job for a competent sparks or youse'll need a syrup to replace all the hair you pull out.

But surely a neutral to earth fault would have to be on one of the circuits so disconnecting each one I should have been able to isolate it ? Unless every circuit has a fault?

 

[telectrix]

not something that can be solved without eyes on site.

 

[johntheo]

With the RCD tripped just put your M.tester between N&E on any socket and check resistance, if infinity, then not a N to E fault as it takes a relatively low resistance to trip the RCD on this fault condition.

 

[Dustydazzler]

Remove all the cables and start again testing then reconnecting one circuit at a time

An experienced sparks should be able to do this and identify the problem circuit(s) in a couple of hours

Might take a bit longer to rectify the problem depending on what is causing the tripping

 

[Aaron b]

I take it that this is an old installation and that a new consumer unit hasn't just been fitted? As dusty said try it with only one circuit connected. If you are removing all of the neutrals it would be worth labelling them. Have you tried isolating the shower and cooker locally? Have you got an immersion heater or outside lights? IMO Those would be the prime suspects.

 

[James]

without the correct equipment to test the rcd, it is not possible to say that it is faulty.

however, changing it for a new one would be a fairly simple job to do, providing it can be safely isolated from supply.

Problem is I suspect that you have no way of testing that the new rcd is functioning correctley, even if the power comes back on and you appear to have no faults.
you could be making the installation more dangerous because it cant detect a fault that is there.

worst case would be that there is a fault on any circuit,
but for example the shower circuit has a live to earth fault.

you change the rcd for a new one that is faulty.
connect everything back up and it all works, therefore "everything is ok?"

wife/parent/child (delete as appropriate) takes a shower and steps on the drain plug
approximately 3 seconds after that, they are lay flat out on the shower floor DEAD

it might seem like I am trying to scare you into getting a professional in, but in truth I AM.
These "accidents" happen almost daily in the uk, everyone thinks that it wont happen to me.

I would never change and RCD and leave site without testing it, for me it is Simpley to protect myself from the courts finding me guilty and jailing me, for a DIY person who has family in the house, the consequences of a mistake are something you will live with for far longer than the prison sentence.

 

[brianmoooore]

Is this RCD 30mA, 100mA or 300mA?