RCD in consumer unit keeps popping, replaced with new one, still same issue

[Cadgey123]

Morning guys!

Over the weekend I noticed that the 80a RCD in my consumer unit kept tripping. The house doesn't have anything particularly power hungry - no air con, no DIY tools. It even trips in the middle of the night sometimes (I know so because the house alarm has a little fit when it detects there is no longer any power and switches to the backup battery).

I am wondering what it might be? I replaced the RCD with a second hand one from eBay, seller has 100% feedback and stated it was tested. Is that my issues (I replaced a duff one with a duff one) or is there something else I should look for?

Here's the unit with the switch pointed out. I have a multimeter at the ready to test, just tell me what to target.

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What a waste of money. It was obvious from the start it wouldn’t be a faulty RCD. You are not going to save money by doing random changes of equipment. Also it’s dangerous as you clearly are not competent to do so.....

 

[Risteard]

What a waste of money. It was obvious from the start it wouldn’t be a faulty RCD. You are not going to save money by doing random changes of equipment. Also it’s dangerous as you clearly are not competent to do so.....

He also doesn't know whether this second-hand RCCB purchased from eBay even works correctly...

 

[Octopus]

What a waste of money. It was obvious from the start it wouldn’t be a faulty RCD. You are not going to save money by doing random changes of equipment. Also it’s dangerous as you clearly are not competent to do so.....

Disagree about the faulty RCD .... that does happen, rarely , but ...

 

[123]

Disagree about the faulty RCD .... that does happen, rarely , but ...

If called to an RCD tripping your first port of call is never to change the RCD, or randomly change any parts for that matter.

 

[Octopus]

If called to an RCD tripping your first port of call is never to change the RCD, or randomly change any parts for that matter.

Hit, nail and head springs to mind

 

[Andy19]

No need for any replacing of bits. First job - sort out the shared neutrals that are as plain as day!

 

[123]

No need for any replacing of bits. First job - sort out the shared neutrals that are as plain as day!

Consumer unit is a bit of a botch and a mess...but I don't see these as plain as day?? The fault would be far from intermittent and easy enough to find if it was shared neutrals.

Look at the busbar in the original picture, the 2 MCB's to the left are also protected by the RCD in a somewhat "bespoke" arrangement.

 

[UNG]

Disagree about the faulty RCD .... that does happen, rarely , but ...

Not as rare as you might think I don't change that many consumer units but I have had two that had faulty RCD's brand new out the box and another that I found while doing some other work for a customer that wouldn't trip within the rated time and current about 6 months after installation

 

[UNG]

No need for any replacing of bits. First job - sort out the shared neutrals that are as plain as day!

Normally it is the shared live not the neutral that is the problem but I doubt it in this installation

 

[Cadgey123]

Disagree about the faulty RCD .... that does happen, rarely , but ...

So you are saying it would be more likely a faulty RCD rather than a Circuit fault? Disagree

 

[Octopus]

So you are saying it would be more likely a faulty RCD rather than a Circuit fault? Disagree

I was disagreeing with the post that ruled out a faulty RCD ....

Tripping RCD's can be caused by:

1. Issue with the incoming supply
2. Faulty RCD's
3. Earth leakage from appliances
4. N-E faults on RCD circuits
5. N-E faults on non RCD and RCD circuits
6. Faulty appliances

etc etc

 

[Chivers]

The shower is still working but doesn't get used? The Neutral and earth are still connected even if the MCB is switched off (others have mentioned this). When RCDs trip I always think water or poor insulation resistance. I'd be tempted to remove the shower neutral & earth (and tape up) in the first instance unless it can be totally isolated? This will eliminate that circuit without an unnecessary disruption to circuits that are being used.
It does seem odd to wire the RCD in with circuits either side rather than just to the right with one length of bus bar - looks like it's been an afterthought.