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We have two RCD circuits downstairs. One for the new kitchen extension and one for the 1948 original ground floor. The RCD for the old circuit has tripped. Only noticed when we tried to vacuum the living room and the vacuum wouldn't turn on.
I have unplugged everything from the affected circuit and turned all the sockets off but it still trips. It push the switch up and it immediately flicks down.
We haven't been doing any decoration, renovation or general buggering around with the electrics. It all was fine yesterday and then it wasn't this afternoon.
Anything else I should check / try before calling a competent sparky in the morning?
Can you swap the RCDs over to eliminate it?
Your description points to a short circuit, either live to earth or live to neutral.
Possible:
Damp?
Nails/screws been put in walls/floors?
A loose connection has finally come undone.
Most likely - A socket has an untidy mess of cables behind it, the socket was tightened up,squashing the cables as it was tightened, it seemed alright, but over time the PVC insulation has crept, now 2 wires are touching.(this can happen anywhere where cables can be compressed, one had been there 10 years, behind some nailed on metal capping.The cable was slightly trapped, 10 years later, the cable touched the metal capping, and tripped the RCD)
Unlikely:
Fried Mice in the back of a socket. (I've seen this twice, I couldnt believe the mouse could get in the tiny gap)
Socket has burnt out/failed internally, causing a short.
Possible:
Damp?
Nails/screws been put in walls/floors?
A loose connection has finally come undone.
Probable:
A squirrel with a grudge
Could be rats or mice, they love to nibble cables
Of the circuit is off, I'd have a peak behind each socket and switch for any obvious signs of arcing.
I will swap the RCD to eliminate that and tomorrow have a play with pulling the sockets. Thanks!
If I haven't posted back this time tomorrow, carry on, carry on, nothing seems to matter anymore
How confident an electrician are you?
We had this at the end of last year, the cause was damp getting in the wall and getting into the knock out box, caused a bad earth.
I took some advice from a sparkey friend who suggested some things to try to locate the issue:
Turn off and disconnect all appliances from the affected circuit (done).
Remove each face plate in turn, inspect for short circuit/corrosion.
Remove each socket in turn, isolating each of the wires so they can't short, then turn the RCD back on. This 'should' identify a dodgy socket, as long as they are all on a ring main. Replacing the face plate would be the easiest solution, unfortunately I had to change the knock out box in the wall for ours, a right PITA but saved a few quid.
IANAE mind, and am quite happy to do these things myself, YMMV.
We had one doing the same. Turning the power off completely, resetting the tripped RCD and then switching the power back on worked for us. With the power still on it kept tripping immediately.
Very unlikely to be a faulty RCD, but read on.
When you say you have turned off the sockets, what other circuits are on that RCD?
Or, have you eliminated it down a bit, and all other circuits are on, but do not trip the RCD?
If the Circuit breaker for the socket circuit is off, then it has to be a neutral to earth fault, as it cannot be a Live to E/N fault, as there is no live leaving the circuit breaker. There has to be other circuits attached to this RCD for that to happen.
Now, if all circuits are off, and it still trips, then it still could be a neutral to earth fault, though more likely to be a faulty RCD, but, to be sure, all neutral outgoing circuit cables from that RCD should be taken out of the neutral bar.
If it still trips with all neutrals out, and all circuit breakers off, then it is a faulty RCD.
I guess it's not the oven circuit, but mine caused issues when an element wore and started shorting.
Not likely to be damp at the moment unless you've got a leaky pipe somewhere or shower / bath is leaking. Might be worth starting with sockets that might be close to possible sources of leaks, got to start somewhere.
Okay, thanks for all the advice.
No, not likely to be damp etc.
Badly wired sockets is my best guess as we found speaker wire used for the lighting circuit when we had a problem there.
The big box with all the RCDs in it has two banks of six. The main switch for the left bank trips before the particular faulty RCD.
I switched all 12 off. It flicked on the 2 main (bank of 6) RCDs without issue. I then flicked on each of the six individual RCDs for the right bank without issue. I repeated for the left and identified the "Old Ground Floor Sockets" circuit as the culprit.
I will open and inspect the sockets but a bit puzzled by the fact we hadn't been doing anything to provoke a change. Anyway, if I am not dead tomorrow I will report back.
From that last post it sounds like an MCB not an RCD that is tripping?
Sounds like your consumer unit is reasonably modern, in which case, an RCD usually protects a bank of circuits and each circuit is protected by an MCB (a modern RCD is twice the width of an MCB)
If the RCD is tripping instantly, then there is an alternative path to earth.
If the MCB is tripping instantly, then there is a short between live and neutral.
Quite often people forget about a socket that's hidden somewhere that has been forgotten about and still has something plugged in?
If there is genuinely nothing plugged in and there are no fused spur connections or anything else, then it can only be the MCB/RCD or the cable or one of the sockets.
Without a test kit it would be difficult to narrow down where a cable fault so hopefully you'll find something at the back of a socket - for the love of Kona, make sure the circuit is isolated (both RCD and MCB turned off) before you start taking socket fronts off.
Thanks Wiksey. I will be careful I still remember the full 240 when up to my shoulders in a pond and someone turned the mans back on so there was better light. Much sore arm I assure you and no trust of others when working.
Is the oven, boiler, hw tank or anything else wired into this circuit? I had similar and it was the electric valves on the boiler getting wet that caused it
Unless you know where the wiring actually goes, I wouldn't trust that the sockets you think are on the isolated circuit actually are. I would have the main switch off before opening sockets.
Your login name goes before you.
Okay - I have an hour before my next meeting. Let's see if I can trace the fault.
1) Power off
2) Remove socket face and visually inspect
3) Poke the wires and tighten if required
4) Flick the mains back on to see if it still trips
5) Repeat for the remaining sockets
Anything I have missed?
1a) double check nothing plugged in to the socket you are about to remove, still powers on.
and thick rubber soled shoes for the, er, staying alive.
Power to the problem circuit off
All faceplates on this circuit removed (leave cables connected) for a visual inspection.
Turn power on to circuit to see if it trips!
If it doesn't trip, best thing to do would be to screw one faceplate back on at a time, with the power off.
Trying to switch the power back on screwing every faceplate back, until you get to the one that trips!
double check nothing plugged in to the socket you are about to remove still powers on
This. I electrocuted myself once wallpapering round a faceplate in a room where flicking the 'sockets' MCB killed the radio on a different plug. The previous owner (WHO WAS AN ELECTRICIAN!! 😡 ) had spurred it off the lighting circuit.
It sounds like you've had a have a go hero playing with your electrics in the past (speaker wire used for the lighting circuit). While you've been looking at the backs of sockets, they would normally only have two sets of wires connected there, the earth cables should be sleeved and only one colour scheme present (red/black or brown/blue). Any visible copper (should only be on the earth) shouldn't show any signs of corrosion (going green), no debris/salting in the back box.
If you're finding anything other than this it helps narrow down the area that might be at fault.
If more than 2 sets of cables are in the back of a socket then a spur has been added and you will find another socket with only one set of cables, but there should never be more than one spur from a socket.
If you're finding none of the above then I'd be inclined to think it's cable damage somewhere.
3 hours ago, is WCA still alive is the question? We all hope so!
Whilst you're looking in the sockets, check for any random extra cables where someone has spurred off to power something else, it could be you have something still connected you just don't know the socket is part of that ring main.
A basic socket tester is quite handy, they plug in and make a noise which you should be able to hear from the fuse box and you can then find out which circuit each socket is one by trial and error...
https://www.screwfix.com/c/tools/socket-testers/cat7910008
I've got a few, can post you one to play with if you get stuck...
I have checked all the easy to get to sockets and most appear to be daisy chained together with two black, two red and an earth and all look okay. Next I have to start taking down book cases etc to get proper access to them 🙁
It seems strange that they just 'failed' when not being actively used. The TV box was plugged in and running but other than that it is just lamps and the stereo. Only realised there was an issue when the wife plugged in the vacuum and have checked the socket she used which was fine.
I am beginning to think if might be the RCD but not sure how to test that
Must be a local to you spark on here who would have an RCD tester!
I wouldn't have thought that the vacuum was anything to do with it and although it's possible for the RCD to fail it's not common. From what you're saying it's sounding more like a damaged cable somewhere, but without a test kit or a way of safely isolating sections of the circuit I can't recommend a way for you to try to narrow that down.
If turning on the MCB for the downstairs sockets causes the RCD covering that bank to fail then there is an alternative path from live to earth on that circuit (there is a common busbar for all neautrals on that bank and another one for all the earths). If you have metal backboxes pay close attention to the sleaving on the cables when you're looking in the sockets - a small nick in the live (red) coming into contact with the backbox would cause your problem, but wouldn't explain why it has only just started.
Round here I would be looking for rodent damage by now.
Good luck
I am beginning to think if might be the RCD but not sure how to test that
Simplest way is to just buy a new one and swap it out, they're only a few £.
Just going to call a local sparkie as I can't see anything obvious and don't have the knowledge/tools to go much further
Oh, and if it's only that circuit that causes the RCD to trip then it can't be the RCD that is at fault, it has to be a fault on the circuit itself.
Had exactly this happening last night, suddenly at 6pm, half the house tripped out.
After experimentation, unplugging stuff and flipping switches we thought we had it narrowed down to the new garden light circuit but strangely even with that off the circuit tripped as soon as we placed any load on it, kettle, microwave, plug in a PS4 or indeed it tripped after about 10 minutes if just left.
The electrician who had put the lights in was good enough to come out at 9pm, change the switch for a fused spur (which proved it was the new lights as they could now be isolated), track down the guilty party in the circuit (by torch light) and remove it for replacement as it turned out that one of the light units itself had failed rather than a problem with their wiring.
So I'll be using him again for any work (Kiblec in Stonehouse nr Gloucester in case anyone wondered) as we've had a few problems with "diva" electricians over the years not finishing jobs and not turning up when expected.
baldiebenty - inside the consumer unit there is a common busbar for all neautrals on that RCD and another one for all the earths so the fault can look like it's on a different circuit to the one its' actually on. WCA is saying his fault only trips the RCD when a particular MCB is turned on but with no load applied, therefore it must be on that circuit.
You really need to get an electrician to perform an insulation test on the circuit. A neutral to earth fault will also trip the rcd and as all neutral and earths are common in connection it may actually be another circuit that is causing it. As said before if it’s the rcd then there is a current leak to earth ( not healthy) if it’s the mcb it will be a short circuit between phase and neutral or earth. Still not healthy. With test equipment it will be easy to discover it’s not something you can guess at because you don’t know what the fault is. You could stop the rcd from tripping but not solve the fault leaving the circuit dangerous. If you have a sparky mate get him in and tempt him with beer 🍺
A left field theory but do you have an external earth rod sunk into the ground/garden?, if so the very dry weather may be at fault
We had an earth rod put in when we had the kitchen extension put in. Prior to that the house had no earth apparently.
Sparky due tomorrow morning
Oh, and if it’s only that circuit that causes the RCD to trip then it can’t be the RCD that is at fault, it has to be a fault on the circuit itself.
you say that, but I once put a screw thru part of a lighting circuit in my house. It was summer so we weren't using lights much, but using sockets (definitely on a different RCD) would pop the RCD. I think it might have popped the overall one, rather than the one for that individual circuit. but the light circuit remained open (which took AAAGES to debug)
Saturate the ground around the Earth Rod and see if that makes a difference
Last time I had anything like this it was a faulty outdoor light. most annoying as it was intermittent too.
i'be checking for any fused spurs off any of the circuits.
There must be something still wired in causing a fault. Failure of RCDs seesm unlikely, and failures of cables also seems an odd thing but if they're Red/black shows theybe been in there longer than 10 years.
If you've checked all the sockets wiring and you're convinced there's nothing plugged in I'd have thought its a hard wired device (eg outdoor light) or one of the sockets has died and is causing an earth leak.
A test screwdriver costs a pound and is always good to use before you touch anything even if you think it's off.
I'd:
Disconect everything from the breaker and see if it trips. If it doesn't the problem is down stream.
Work along the daisy chain disconnecting the end of it. You'll find out at what point the problem starts. Then leave the end section disconnected and test each section of it. You can make up a cable with a plug at both ends to power the disconnected sections to test them.
Once you've identified the bad section pull a new cable through or replace the component that's causing the problem.
Would a fault at an earth rod do this? Doesn't the RCD trip because there is a difference of more than 30ma between live and neutral indicating that something is going to earth. I'm not sure how not having an earth would cause the problem. A lose earth touching something might be the problem and given that inside sockets the earth wire might not have been sleeved properly there is always the chance that something has moved enough to create a contact between earth and a live or a neutral
Traced to a broken wire between house and conservatory.
Electrician was a bit surprised by the house wiring. All ground floor plug sockets off a single 20amp circuit breaker - single spur, not a ring main. Cable went from fuse box to furthest socket in the dining area then back towards the kitchen then back across the dining room etc. The wires also changed colour and size between the sockets making tracing a challenge. There was then a mini ring main in the conservatory to power 2 plug sockets and the lights.
As the mini ring main was running of a single wire and not a proper ring main it was pretty pointless and it was one of the two wires connecting to the main house socket that was faulty. Fortunately by disconnecting the faulty wire, the other leg worked fine. The faulty wire was capped at each end and we have power back.
Breathes sigh of relief that WCA is OK