Electricity rcd tripping

Hi last few weeks my rcd on the lights, sockets and shower circuit (also has fridge and freezer on it) has been tripping the rcd but not the individual circuit breaker

I’ve unplugged all appliances bar the fridge and freezer, turned off shower and sockets and lighting at the board bit it trips still , am I correctly assuming that if there was a problem with say damp in a shower that having it switched off at the board would stop it tripping and thus point to the fridge and freezer, ive not unplugged these yet as they are built in and a pain to get at

Bloody electric, it started some days after we got the little lad a vivarium and a snake , it blew a heater bulb and has been a pain since ( the rcd didn’t trip with the bulb and it still trips when unplugged completely so I think it’s ruled that out

I’m trying to track it down prior to an electrician coming out as it’s an intermittent issue

Cheers

I had this a while back – RCD tripping but not individual MCB. I turned off all the MCBs and switched each one on in turn until I found the circuit that was tripping, left it isolated and was then able to restore power to the rest of the house. Turns out one of my ‘weatherproof’ outdoor lights was full of water. In this case, can you turn off the MCB for the 13A sockets to the fridge/freezer and everything else stays on? It might not be an appliance, but a loose wire or broken insulation inside a switch socket.

RCD is for an earth fault, MCB is for overload, or L/N fault

It could be anything – they are a nightmare to find – it could well be your appliances – but also, the motor circuits in your appliances can also trigger a trip on an unrelated wiring fault

RCD’s also measure (sometimes) the load on the live, compared to the return on the neutral – so a loose neutral can cause a trip

Unplug the fridge and freezer too. It won’t be harmed by a few hours without power if you keep the doors closed.

Fridge freezer is actually a common one for tripping them.

Cheers I’ll look to isolate the fridge freezer and see what happens

I ‘eventually’ found the plug socket for the fridge and freezer had ‘gone faulty’ – took ages to find the fault.

Lol nightmare my next plan is to pull out the freezer tomorrow and try plug it into the other ring with an extension lead as a temporary test, id thought If it trips the other ring it’s the freezer , if it doesn’t ill put something in that socket now good call

RCD’s also measure (sometimes) the load on the live, compared to the return on the neutral – so a loose neutral can cause a trip

That’s all they do, measure the live out and neutral back. If there is an imbalance, then it trips out.
OP, it will likely be your fridge. As mentioned above, unplug it completely. See if it trips.
Or, unplug everything else, open the fridge and freezer door, wait for it to start up, and see if the RCD trips.
It is important to unplug everything. Even plugged in, with the plug switch off, the neutrals can still be connected in the appliance to the neutral terminal. Cheap socket outlets only siwtch the live, not the neutral.
And, as said above, see if you have anything that may have got slightly wet internally.

If it still trips when everything is unplugged, then it looks like you have a wiring problem. A loose connection is unlikely to cause this, it will be a dead mouse behind a socket, water in a socket or insulation worn through very slightly at a tight spot in the wiring/back boxes.
I’d put money on the fridge.

My only other thought of water ingress was the shower , ive turned off the shower power switch and turned off the board breaker but could it still trip the rcd as its still connected cheers

Not that I’m endorsing this but it’s no doubt an earth neutral fault so the best way to isolate the exact circuit that is affected will be to remove the neutrals one at a time from the neutral bar in the consumer unit until you can reset the RCD without it operating. This will be the circuit that’s causing you the issue. If it’s the one with the dodgy kitchen appliance on the this is your likely culprit….if it’s a lighting circuit then most likely a loose connection at a pendant…or fitting.
Thing is that by removing the neutral (not endorsing this unless you are qualified) it will enable you to get the rest of the circuit back on and you can then investigate the problem circuit when you have time….not on Sunday night.

The trouble with that rather dangerous to me method is this lasting anywhere from 10 to 35 hours between tripping so I’m somewhat baffled tbh

I must retract the previous advise as I’ve just actually read the post and you say intermittent issue so not that the RCD cannot be set…you have functionality for the most part so not a catastrophe until a sparks can come out and sort the issue….soz..I’ll read the damn post first before I give last ditch advise.

Lol could a dodgy neutral light pendant still trip an rcd when the whole circuit is off at the board

Yes because earth and neutral are linked at the service head (if a PME system) which most houses are so the fault can track through as the earth and neutral are common. The removing of the neutral at the bar in the consumer unit (only to be done by compatent persons) will remove the common connection and enable you to identify which circuit has the fault. This only really applies when the RCD cannot be set at all and crashes out each time it’s energised so not really applicable in your case….hence my swift retraction. It could also be a duff RCD that needs replacing. The sparky will do a half current test (below the threshold that the unit should operate) and this will tell if this is the issue.

Bugger I’ve been thinking I’ve narrowed it down by knocking off circuits when in reality I’ve done nothing

As I said it all started when the lad got his new tank and it blew a heater bulb but the socket looks fine
My only worry was the shower as I can actually see some wire at the back, if I disconnect the ceiling on off pull switch will this isolate the possibility of a dodgy earth in that as that’s a possibility tbh

If it’s a 40A pull switch it should be double pole and should open both live and neutral contacts so should isolate it. I assume the shower is a dedicated circuit? If it’s just a pumped shower and the circuit feeds other items then this may not be enough to fully isolate it…due to bonding on pipework etc.

It’s a normal pull what ever that is lol 2 blue 2 brown 2 n so I presume double pole

This is a mare, I guess pull out freezer tomorrow and if no look I better get looking for an electrician in Leeds

Cheers mate

Water in outside light was mine.

Ours goes when there’s an LV fault on the DNO network.  I think the DNO have a dicky neutral somewhere and it’s coming back through our house’s earth.

(yes I do work for the DNO and yes I have had a word with our repairs guys)

PS – yes your RCD can go for a broken neutral / earth a few streets away on someone else’s system.   Trust me, I’ve been doing this for 30 years.  Depends on the various earthing systems and how well they are installed / their condition.

Just to add to what alanl said above, If it’s a dual RCD board when you unplug the fridge/freezer plug it into a circuit on the other RCD and see if the problem moves with it.
It’s usually fridge/freezer or whatever is the most awkward socket to get to 🙂

Do the above. FWIW I’ve had water ingress trip once, faulty tumble dryer another time.

I’ve fully isolated the shower and it’s not tripped for 22 hrs so fat, but it has lasted 35 before so is a waiting game, a smelly waiting game lol next trip it’s the freezer out job cheers all

My money is on moisture in the shower causing a N-E fault. You only need the tiniest amount of moisture in there to trip the RCD. Just turning off the breaker at the CU wouldn’t have isolated the neutral, you’ve now done that by clicking the DP pull-cord isolator to off. If it now doesn’t trip then it’ll be a N-E. Check the seals around the front plate of the shower, but if it were me I’d be replacing it completely. You don’t want to be in the shower and risk getting a shock, RCD protected or not. 30mA isn’t enough to kill you (usually), but it’s bloody unpleasant and not an experience you’d be queuing up for.

Hopefully as that will be much cheaper than a new fridge freezer , fingers crossed

It’s a nightmare. I’ll add into the faulty ‘plug socket’, water twice in an outside light – worse one as it’s half way up the house wall and involves leaning out of a bedroom window, and also a bit of metal chain flying round the ‘dryer’ and ending up shorting the heating elements. Managed to rescue that, but had to pull the dryer to bits.

Check your tumble dryer filters aren’t blocked if you have one, this caused my trip to go but only when the dryer was running. Cleaning cured it.

My issue was a dodgy power socket that had a built in usb charger.

Well 28hrs later tripped now I have the freezer on the other ring, see what trips now

Just to add to the excitement of this saga don’t neglect the idea that it could be a cumulative effect of the combined circuits attached to the RCCB causing it to trip, your appliances maybe fine individually but a small spike from say a fridge compressor on start up may tip it over edge.

Lol nothing would surprise me currently but ive had everything unplugged apart from fridge and freezer previously with all light circuits off and shower off and it still went off
Knowing my luck the lads snake tank heater popping fried the rcd although it didn’t trip when it went its only started days after getting it

We had this, called a local Electrician who tracked it down to a damp socket downstairs.
He unplugged everything in the house, which still tripped the RCD.
The socket was on an external wall which was being effected by a leaking gutter. The rain was running down the external wall.
T’was a PITA to track down

Given all the varying advice supplied in this thread, and the OPs questions – I’d be getting an actual electrician in to test everything properly. It’s not something you really want to get wrong.

You are correct Ben but I’m just trying to discount all the appliances first before wasting the electricians time and my money, but im not touching anything that’s dangerous, ive done that before and never again

This happened to my work recently. An electrician said when the rcd box get old and the switch is never operated it can start tripping itself. The switch was swapped for a new one after switching off all the power to the building and so far is fine now.

Yes, I’ve had to change a few Wylex RCDs that developed a random trip. Probably 6 years old now. I always thought they must have made a bad batch, as they were all the same age.
When tested, including a ramp test, they were fine, but still carried on giving random tripping, and, once changed, no tripping.

Your fridge freezer is on the RCD side of your consumer unit? Safety first I suppose. If you’re interested in food preservation you could consider moving its supply to the other side of the RCD. That way when you’re away for a few days and, say, a security light suffers some water ingress you won’t return home to a wet floor and rotten food.

Well plugged it into the other ring circuit and it tripped that ring rcd so obviously something amiss with the freezer
Cheers all

Your fridge freezer is on the RCD side of your consumer unit? Safety first I suppose.
you could consider moving its supply to the other side of the RCD.

No, in this situation you could consider upgrading your consumer unit to one with each circuit on an RCBO.

Well plugged it into the other ring circuit and it tripped that ring rcd so obviously something amiss with the freezer

Told you!
Its pretty common. I remove any appliance with water first, as they are the most likely to trip RCDs. Kettles, boilers, Immersions, washing machines etc.
Thats after discounting any water getting into lights/sockets etc.
Then it’s the fridge/freezer. They fail that way usually, not an overload, but a neutral to earth fault that trips the RCD.