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

[Cupa]

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.

 

[Bobster]

Target your phone and call an electrician in.

You wont be able to find the fault with your multi meter.

It's most likely an appliance that's faulty. Maybe a fridge or freezer. Could be a central heating pump.

Are there any patterns as to when it trips?

Edit: It will be something on one of the circuits fed from the MCBS on the right hand side.

 

[Cupa]

Hi Rob, thanks for the reply. Would you really think that it is the central heating pump? It is summer and we don't put heating on past about April unless it is really bad.

As for patterns, it seems to go off in the middle of the night at times, it is a small home and when it goes off, everybody is asleep, so aside from fridge and freezer there isn't really anything else that is on and power hungry.

It also goes off during the day sometimes, but at that point more is in use, so to me there doesn't seem to be a definitive pattern ie. goes off when something is switched on.

 

[Bobster]

The 80amp rating isn't what it will trip at, but rather how much current can safely 'flow' through it.

It will actually trip at 0.03amp. Current needed for it to trip has to 'leak' from either the live or neutral wire to earth in any circuit that it protects.

This isn't a technical explanation, but I hope it's made it more clear.

The test gear you will need to find the problem is expensive. An then you likely wont know how to use it or understand the readings. It shouldn't be a difficult task for an electrician to find the problem for you. However, intermittent faults can sometimes be a real pain to find.

What do the 4 circuits on the right of it feed?

 

[Darkwood]

As above - it could be many things and if intermittent and at random times it maybe an appliance like your fridge, it also maybe related to water ingress if you are feeding a shed or garage from that side of the board, like above can you identify the 4 circuits it effects and we can hazard a better guess.

 

[streamer]

It also looks like someone has bodged the busbar set up in the consumer unit so the RCD is feeding the two circuit breakers to the left of it too.

 

[Pete999]

How residual current device (RCD) works? - http://electrical-engineering-portal.com/how-residual-current-device-rcd-works
Might go someway to explain how an RCD opperates, as stated you probably have a faulty appliance, or a faulty circuit, best call an Electrician in to check the installation, your Multi Meter will be useless in finding the fault. Not sure I agree with the cable link acting as a Busbar for the MCBs at the far right of the Consumers Unit either. Replacement Bus bars are very cheap and easy to change, not by yourself I hasten to add. Safe isolation procedures need to be followed in order to Isolate the supply.

 

[Risteard]

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.

View attachment 42840

View attachment 42841

Seriously?

 

[Cupa]

Interestingly enough, this unit was fitted about 10 years ago by a qualified NICEIC person - so not sure why a bus bar wasn't used. I should have changed that when I changed the RCB, they are only a couple of quid.

On the four MCBs to the right of the RCD, there is:

1. Electric shower (which is never used)
2. 1st floor sockets
3. Lights
4. Wall lights (not sure what that is, need to investigate)

 

[telectrix]

if that RCD is feeding the 2 MCBs to it's left, looks like they are socket rings, so that's a fair starting point. appliances. you could try switching off each one separately for a day or so ( obviously use an extension lead from the other if it turns fridge/freezer.essential equipment / off.). if the tripping stops, the fault is on the isolated circuit. this is onlyas rough and ready approach as it won't isolate a N-E fault. to be honest, previous advice to call in an electrician will save you chasing your arse and pulling your hair out.

 

[Wilko]

Several "oh dear" moments when looking into that board. Most likely the RCD wasn't / isn't malfunctioning, sorry. For safety, please put the cover back on - now .

 

[Gavin John Hyde]

Interestingly enough, this unit was fitted about 10 years ago by a qualified NICEIC person

There is so much we could say with that statement... But i will resist temptation...

 

[Octopus]

There is so much we could say with that statement... But i will resist temptation...

I think that's a bit unkind ... It's worked for 10'years.

That said a multi metre isn't going to be much help

 

[Cupa]

There is so much we could say with that statement... But i will resist temptation...

Such as?

 

[Pete999]

Such as?

4 words describe it well "Bit of a mess"

 

[Darkwood]

As it stands we can help you by suggesting what could be the cause and because you are DIYer we can only advise on possible appliances that you can unplug and try to eliminate but lets make it clear that you are playing with very dangerous voltages here and you have taken the cover off and exposed live busbar rails given the position of the main switch is ON.
The advice to you is try unplugging various items for say a week at a time overnight and see if you can clear the issue, if this fails then you need to get a competent person in with the correct meters to check your circuits.
Just remember at domestic voltages it can easily kill you even with one small shock so ensure all covers are back on and see if you can resolve this without the need to expose live parts.

I would also check to see what the weather is when it has tripped, is it windy, is it or has it been raining, these would possibly lead to possible causes like exterior lighting, garage/shed power etc etc I would also list everything that is on when it trips, are you running the washing machine overnight?.. it may trip on a particular part of the cycle, these are easier issues to verify of what can be a lengthy issue to diagnose and trace given it is intermittent.

 

[johnduffell]

those live busbars are missing some basic protection, there must be some form of plastic cover over them unless isolated. (turn off the power, put the lid back on)
you could easily rule a lot of things out with an insulation resistance tester and the knowledge to use it properly. Any decent electrician could do that for you. And also sort out the busbar and the shrouds for it.
If you want to save the cost get unplugging things and use trial an error to work it out.

 

[telectrix]

h

4 words describe it well "Hell of a mess"

corrected that for you.

 

[littlespark]

I just want to add - It doesn't matter if the appliances are turned on or not... the RCD can detect faults to earth from live or neutral.
Appliances plugged in but not switched on at the socket can cause trips.
Permanently connected equipment such as cookers or showers can trip RCD's off if the fault is on the supply side of their isolator switches.

As mentioned, intermittent faults like these are a pain for the best of us to find.

Buying anything electrical off ebay is hit and miss. Go to a local wholesaler / big orange shed, at least you'd get a guarantee.
Or employ the services of a spark.

 

[Cupa]

Thanks for the suggestions and advice guys. I will trial and error test by taking sockets out / switching off appliance and report back. Will also fix the busbar.

 

[Octopus]

Thanks for the suggestions and advice guys. I will trial and error test by taking sockets out / switching off appliance and report back. Will also fix the busbar.

Bad idea IMHO

Get it fixed by all means but fiddling around inside fuseboards is not a sensible idea.

I would suggest when you can't find the cause of the tripping, then ask the spark you get involved to sort it for you....

 

[MJPD29]

Replacing the rcd will do nothing but waste your money if there is a fault which is most likely

 

[static zap]

Get another rcd socket / extension and put everyones phones/chargers in quarantine zone--on over night charge !
( -Electrician will have gear and experience-)
Any signs of rodents (they do night-shift)- could spell danger.

 

[telectrix]

????

 

[westward10]

????

Buzz's cousin.

 

[static zap]

Buzz's cousin.

Buzzing noises at night , usually a problem !
--No simple explanations--

 

[123]

Better to bring in a good spark. A huge false economy changing parts randomly just to find out all you needed was a new kettle.

Was at a job a few months ago, the so called Heating Engineer on a heating fault replaced the boiler, 3 channel programmer and a few other bits to the tune of 4 grand. It was the UFH pump that was faulty all along. Idiot. The customer engaged the same idiot to change the pump. I'd have been seeking legal advice for costing me wasted thousands.

 

[Cupa]

Morning folks. I have been a recommended a good electrician but he is only able to come and see me next Thursday. Been quoted £150 for the chap to set aside half a day.

While I am waiting I would like to do more fault finding, because the issue is that as soon as the RCD trips, the house alarm goes ballistic because it thinks somebody is trying to bypass it. It went off once at 3am and today at 7am....I apologised to the neighbours by they were not happy (understandably).

Went to bed last night and before doing so, I switched off the 4 x MCBs to the right of the RCD:

1. Electric shower (we never use this, it does work, but we just don't use it)

2. Sockets first floor (on the image it is on, ignore, at the time of going to bed it was down / off)

3. Lights

4. Wall lights

So only the Ring Circuit 1st Floor and Ring Circuit Ground Floor was on. And at 7am, the RCD tripped.

My plan is to repeat the above experiment again, but this time, in addition to having the 4 x MCBs to the right of the RCD in the off position, I shall disconnect anything plugged into the mains ion the 1st floor.

I am wondering if a lose wire is touching the back box or earth? We had some screwless sockets installed about 7 months ago, perhaps that is the cause?

 

[telectrix]

the alarm shouldnot activate on loss of mains supply. think you'll find that it's back-up battery is U/S. as for your shots in the dark, you think you've eliminated the circuits that you have switched off, but you're wrong. a N-E fault would still be present.

 

[Wilko]

What does your hot water heating and central heating? Does anything come on at 7am? Is that a repeatable time for the trip? As @123 mentions, boiler pumps can cause this ...

 

[Bobster]

Did the tripping start after the sockets were worked on?

If so, you've missed giving us some important information.

Like having a mechanic look at a noise on a car then after time investigating, telling them that it started after you hit a pothole.

 

[Bobster]

Did the tripping start after the sockets were worked on?

If so, you've missed giving us some important information.

Like having a mechanic look at a noise on a car then after time investigating, telling them that it started after you hit a pothole.

 

[Cupa]

Thanks for the replies. In the summer months, the hot water is controlled manually. We have a big tank and there is only 2 of us, so we tend to warm it up once a day and then switch off completely. So there is nothing programmed to come on or off boiler wise.

The sockets were done some months back as I said. There were never any issues and no tripping. This issue only materialised in the last week. We have not bought or plugged in any new equipment during this time.

 

[johnduffell]

You might want to get the alarm put into its own rcbo to reduce the chance of issues. And also make sure the battery is good as mentioned above.

 

[acvc]

What are all those black neutrals doing on the right-hand neutral busbar?

 

[streamer]

What are all those black neutrals doing on the right-hand neutral busbar?

If you look closely you'll see that the RCD supplies the two MCBs to the left of it as well as those to the right.

 

[Cupa]

Update for you guys. Went to bed with the shower, first floor sockets, lights and wall lights MCBs all in the down position and all plugs taken out of their respective sockets - result? Still trips the RCD.

Next step was to try and see if perhaps it is one of the MCBs to the left of the RCD: ring circuit ground and first floor.

I noticed that when the ring circuit ground floor MCB was down and everything was unplugged, there were no issues and the RCD didn't trip. However, and not always, but sometimes when I would flick that particular MCB up (we keep our bins and recycling in the garage, which has an electric door and this operates on that circuit), the RCD would immediately trip....does that tell us anything new or useful?

 

[Risteard]

Update for you guys. Went to bed with the shower, first floor sockets, lights and wall lights MCBs all in the down position and all plugs taken out of their respective sockets - result? Still trips the RCD.

Next step was to try and see if perhaps it is one of the MCBs to the left of the RCD: ring circuit ground and first floor.

I noticed that when the ring circuit ground floor MCB was down and everything was unplugged, there were no issues and the RCD didn't trip. However, and not always, but sometimes when I would flick that particular MCB up (we keep our bins and recycling in the garage, which has an electric door and this operates on that circuit), the RCD would immediately trip....does that tell us anything new or useful?

You (who has randomly replaced parts with ones of unknown origin from eBay!) are not competent to be diagnosing this issue. That is what this (and everything else you have written) tells us.

Contact an Electrician. That is the ONLY answer to this. Stop messing about with it - you clearly don't know anywhere near enough (if anything) about it.

 

[davesparks]

I noticed that when the ring circuit ground floor MCB was down and everything was unplugged, there were no issues and the RCD didn't trip. However, and not always, but sometimes when I would flick that particular MCB up (we keep our bins and recycling in the garage, which has an electric door and this operates on that circuit), the RCD would immediately trip....does that tell us anything new or useful?

It suggests that something plugged in to that circuit might be the source of the issue, or it might not. As this is an intermittent issue it may just be coincidence that the RCD didn’t trip whilst that circuit was off.
It could also be the case that the RCD is now broken as a result of being reset and tripping so many times on a fault.

 

[Cupa]

Thanks Dave - do RCDs have a shelf life?