Intermittent electrical fault

Blowheads

Hi All,
Hopefully some expert here could help me isolate an intermittent electrical fault in the house. Here is the current situation

• At least once per week the sockets in the house cut
• Only sockets, so lights etc are ok
• It can happen at any time, morning, afternoon, night
• Sometimes it will trip the switch, othertimes not
• Nothing extraordinary is connected only the usual stuff (fridge, clocks, skybox, telephone, baby monitor)
• The issue has occured since we moved in so I could not attribute it to anything in particular
• ESB states there are breakers on the line which cut out and in again if something disrupts it, our neighbours have not complained about this issue and ESB sent out a monitor and it came back that everything was within the guidelines

If anyone has any ideas how to locate the source of this once and for all i would appreciate it. It would be impossible to leave something unplugged for the periods involved as they are the basic necessities.

Appreciate your advice.
Mr. P

2011

Just to be clear, all sockets (and nothing else) switch off and then switch themselves back on after a short period of time?? Please confirm.

If this is the case, the problem is within the distribution board. It may be a loose connection.

muff03

Did you try swapping out the RCD or whatever it is that is governing the sockets? Or at least, like the previous post check the wiring for poor connections? That's where I'd start

hohojojo

could be something as simple as a loose connection in your board or the rcd could be on the way out

i presume it is the rcd tripping never just a mcb?

could be you immersion

there is lots around the house it could even just your a tv thats starting to give

does it reset first time every time you try to reset it?

has this happen since you moved or did it start a while after ?

if the problem persists i would suggest getting an electrician to look at it as if you have no experience with electrical stuff i would like to hear something bad happen ie. fire, shock or worse electricution

2011

ESB states there are breakers on the line which cut out and in again

This is the part I am not clear on. Does it switch back on by itself???

Bruthal

Its an internal problem within the house if the lights are staying on which is stated in the OP.

If all sockets are going off then its a connection problem within the board most likely. This could be a problem within the sockets RCD itself.

It could also be a problem on one circuit, as it would be hard to say every socket in the house is gone off unless you have went around testing them all.

Maybe someone has done something bizare like putting a timer controlling the sockets:D

Take a photo of the board and put it up anyway, and tell us which switch trips sometimes.

Blowheads

Hi all, thanks for your replies. Here are the answers.
1. It's rcd switch that trips, though only sometimes
2. ESB breakers are designed to flip on/off immediately in case a bird or branch touches tge line, that's what I'm told
3. There is no timer used anywhere
4. Power returns immediately, unless the switch is tripped
5. Flipping up the switch always works first time
6. My current sparked says this might never be fixed so am not too confident there
7. I have no clue about wiring
8. Issue started as soon as we moved in
9. All electrical appliances work correctly
10. Attached is pictures of board, top left is the one that might trip



Thanks again

M cebee

he thinks it might never be fixed does he:mad:

i hope he's interested in fixing it

Blowheads

and now the pictures

meercat

try leaving your immersion switched off for a week
also unplug any appliances you are not using(even if they are switched off)
also see if you can switch off central heating at fused spur unit(near timeclock)

muff03

Another quick question: can you think of anything that may have been turned on around the time of tripping, like a kettle or something? Like the above post, process of elimination time now. Also I'm not too convinced by your 'sparks'

meercat

agree muff03
a competent sparks should be able to get to the bottom of this
it might take a bit of time though but an insulation test would be a good start

M cebee

for the self resetting fault (already said)- maybe check connections anyhow

if it's a random rcd trip?

there's quite a few final circuits on rcd!

-if you have the gadgets (which i don't)
-you can ramp test and check leakage

-do the IR test at 250v with L-N bridged

- or even rcbo suspect 'final circuits'

saturday night :Dso i stand to be corrected

meercat

friday
corrected;)

muff03

M cebee wrote: »

saturday night :Dso i stand to be corrected

Hah. you must be in a right way, cause it's only Friday!:D

M cebee

yes it's friday:D

2011

M cebee wrote: »

for the self resetting fault (already said)- maybe check connections anyhow

+1

There is no harm in checking connections. This is quick and easy.

if it's a random rcd trip?

there's quite a few final circuits on rcd!

Exactly.

Split the circuits up across at least 2 RCDs. This alone may solve your problem!

If not, see which RCD trips then you can work out which circuits are OK.

Then further divide the suspect circuits with another RCD. By process of elimination you will work out which circuit is the problem circuit. Once this is identified it should not be too hard to find the problem.

As others have suggested the RCD may also be faulty. This can be tested quickly and easily with an RCD tester.

M cebee

the 'f' key is very close to the 's' key

easily done:pac:

Bruthal

M cebee wrote: »

saturday night :Dso i stand to be corrected

Right no more advice from this fella today, he has had a few scoops already:D:D:D

Bruthal

M cebee wrote: »

the 'f' key is very close to the 's' key

easily done:pac:

A that must be it, you meant to say sriday:pac:

Blowheads

thanks lads, will get onto it, anyone know a really good sparks in galway?

some further clarification,
1. Nothing is plugged in or switched on at the time of the fault, it could happen at any time even when we away from house
2. We dont use immersion
3. Heating turned off last few weeks, still tripping

2011

finneranpaul wrote: »

thanks lads, will get onto it, anyone know a really good sparks in galway?

No, but this would not be considered a difficult job for (almost) any electrician.

some further clarification,
1. Nothing is plugged in or switched on at the time of the fault, it could happen at any time even when we away from house

I would be very surprised if you have nothing plugged in. What about your fridge, dish washer, washing machine, microwave?? Even if they are not switched on a fault could still be introduced.

Permanently connected devices may also be the issue, such as:
Alarm
Oven
Hob
Boiler
Motorized valve

Also the fault may be related to the wiring of the house and not what you have plugged in/connected. This is where your electrician can assist.

2. We dont use immersion

Fair enough, but a neutral to earth fault within this could still be causing the RCD to operate. In theory the immersion switch should not permit this to happen when in the off position (as the switch should be double pole). In practice this may be different.

3. Heating turned off last few weeks, still tripping

See immersion.

I have found that this type of fault is often caused by water. So I would suggest that you check to see if for example there is a wet socket (behind your washing machine/dish washer).

Failing that as suggested before, install an additional RCD.

Bruthal

2011 wrote: »

No, but this would not be considered a difficult job for (almost) any electrician.

Intermittent faults can be hard to find, but with this one, it would seem simple enough to track it down alright.

I would be very surprised if you have nothing plugged in. What about your fridge, dish washer, washing machine, microwave?? Even if they are not switched on a fault could still be introduced.

Yes especially if there is now nothing visual to show the sockets have in fact gone off and the RCD has not tripped.

Permanently connected devices may also be the issue, such as:
Alarm
Oven
Hob
Boiler
Motorized valve

Also the fault may be related to the wiring of the house and not what you have plugged in/connected. This is where your electrician can assist.

Yea, it would be good to check for instance of the immersion is not working during this power off fault but the RCD has remained on. In other words, confirm everything on the top row of MCB`s has gone off, when the RCD has remained on, but the power has been interrupted on sockets.

Sometimes RCD`s, or MCB`s can trip but the outside switch stays up, but in these cases the fault wont reset. But the RCD could have contact problems.

Fair enough, but a neutral to earth fault within this could still be causing the RCD to operate. In theory the immersion switch should not permit this to happen when in the off position (as the switch should be double pole). In practice this may be different.

It shouldnt if its within the immersion itself and if the immersion switch is a proper isolating one and is off though.
EDIT: Just noticed you said that:D

I have found that this type of fault is often caused by water. So I would suggest that you check to see if for example there is a wet socket (behind your washing machine/dish washer).

A good possibility when the RCD is tripping alright.

This fault seems do be like a double fault, a loose connection, and an earth fault. Both could be indications of a problem with the RCD. Or else a loose connection and an earth fault too. Or too many circuits with slight earth leakage adding up as suggested, combined with a loose connection.

Failing that as suggested before, install an additional RCD.

Yes a great idea that one to help find the problem if there is an earth fault, if not, the second RCD might solve that part of the problem anyway. The board could do with a second RCD anyway even with no problems on it.

2011

It shouldnt if its within the immersion itself and if the immersion switch is a proper isolating one and is off though

+1

It shouldn't if wired correctly!

Buford T Justice

I've come across a few cases where the water inlet pipe on a washing machine perishes and has a tiny leak. The water leaks to the electric motor on the machine and every so often it trips...


Worth inspecting.

Bruthal

Thats always possible for an earth fault, but this seems to also have an intermittent off, then back on itself- sort of problem.

Possible a seperate earth fault and a connection problem which could include something like your suggestion. It might well be an earth fault and also a loose connection. Or a faulty RCD.

Or just a loose connection and too many circuits on the single RCD. This loose connection could be the RCD contacts themselves, but will likely be somewhere on/in the RCD or its 4 main flex wires if all sockets are going off and back on themselves. All slight earth leakages will add up on any circuits controlled by an RCD, so a lot of circuits on the single RCD can cause problems.

THENORTHSIDER

poor connection would eventually start burning and would be visable. If your correct when saying nothing is plugged in then it could be a faulty RCD. You could try and change that yourself if you felt competent enough

THENORTHSIDER

possible that you may be inheriting fault from outside your board. Your neighbour isn't doing any type of commercial work in his shed

Bruthal

THENORTHSIDER wrote: »

poor connection would eventually start burning and would be visable. If your correct when saying nothing is plugged in then it could be a faulty RCD. You could try and change that yourself if you felt competent enough

If not much is plugged in, a loose connection could go a fair while without too much burning. It would not be too visible inside an MCB board either.

Intermittent on off problems are often caused by loose connections, whether its a connection in a breaker terminal, or bad contacts in the RCD which is not unheard of. What else would cause the power on sockets to go off, and back on by itself besides a connection problem?

THENORTHSIDER

robbie7730 wrote: »

If not much is plugged in, a loose connection could go a fair while without too much burning. It would not be too visible inside an MCB board either.

Intermittent on off problems are often caused by loose connections, whether its a connection in a breaker terminal, or bad contacts in the RCD which is not unheard of. What else would cause the power on sockets to go off, and back on by itself besides a connection problem?

Changing the RCD would rule out any problem with that both internally and externally. As its on a socket circuit the load should be big enough to generate some level of heat which will discolour the insulation and become visable.

Bruthal

THENORTHSIDER wrote: »

Changing the RCD would rule out any problem with that both internally and externally. As its on a socket circuit the load should be big enough to generate some level of heat which will discolour the insulation and become visable.

Changing the RCD will rule out a loose connection onto itself, and an internal contact problem, as well as a possible tripping fault in it. But a possible loose connection could be on the other ends of any of the 4 wires coming from the RCD to cause all sockets to go from a connection problem.

There are 2 problems apparently. Random power off and back on on sockets, and sometimes the RCD trips. There are too many circuits on that one RCD really.

Also, the loose connection if obvious, may not be visible until the board cover is removed.

Again i would ask, what other problem can cause the power in the sockets to go off, and return by itself, if you suggest it cant be a loose connection or contact problem?

Bruthal

THENORTHSIDER wrote: »

possible that you may be inheriting fault from outside your board. Your neighbour isn't doing any type of commercial work in his shed

Whats the theory on this one?

THENORTHSIDER

This theory of the loose connection (seeing as you are on about theories) it would have to be very loose , as there would have to be absolutely no contact between the cable and the terminal to create an open circuit.A core simply resting on a terminal will allow current flow. Secondly If an installation had an inadequate eathing system ,an earth fault will take the path of least resistance. Welders can also create earth problems. Is that a suitable answer for you:cool::cool: Will head to the college Library Monday for the referances no doubt you will require

Bruthal

THENORTHSIDER wrote: »

If an installation had an inadequate eathing system ,an earth fault will take the path of least resistance. Welders can also create earth problems. Is that a suitable answer for you:cool::cool:

An earth fault may not take only the lowest impedence path, but any paths available.

Its unlikely next doors installation is causing the problems here. They used to years ago on voltage operated ELCB`s, but to happen now is unlikely, but marginally possible on a row of houses with small overhead lines and a heavy load on one or more houses, but it would still need a neutral-earth fault in the installation thats tripping the RCD now. Usually TN-CS eliminates this.

As for the path of least resistance, when you turn on a shower (6 ohms) and a 60w bulb (880 ohms), which one is the path of least resistance? And which path does the current take? Not just the least resistance path anyway.
Most will take the lower impedence path alright, but it still takes any open to it.

THENORTHSIDER

robbie7730 wrote: »

An earth fault may not take only the lowest impedence path, but any paths available.



As for the path of least resistance, when you turn on a shower (6 ohms) and a 60w bulb (880 ohms), which one is the path of least resistance? And which path does the current take? Not just the least resistance path anyway.
Most will take the lower impedence path alright, but it still takes any open to it.

this isn't a fault situation so irrelavent:cool::cool:

Bruthal

THENORTHSIDER wrote: »

This theory of the loose connection (seeing as you are on about theories) it would have to be very loose , as there would have to be absolutely no contact between the cable and the terminal to create an open circuit.A core simply resting on a terminal will allow current flow. Secondly If an installation had an inadequate eathing system ,an earth fault will take the path of least resistance. Welders can also create earth problems. Is that a suitable answer for you:cool::cool: Will head to the college Library Monday for the referances no doubt you will require

No theories, loose connections often cause intermittent on-off problems in circuits. You dont believe thats possble, fair enough. But any competent sparks would clearly know that without library visits.

The OP`s problem is sockets sometimes went off, and came back on themselves. And also sometimes the RCD tripped. Changing the RCD may fix it, as it may be faulty and have bad contacts, or there could be both an earth fault within the installation, and a loose connection in the DB.

Or too many circuits on that single RCD could be causing its tripping problems. Small leakages add up on each circuit downstream of an RCD.

But if you can rule out loose connections causing the on-off part of the problem, on the basis that all a connection needs to be sound is to be touching, then the library might well be a good place to go.

Once that phrase "current takes the path of least resistance" is mentioned, that usually says a lot, as its a phrase heard and then regurgitated without actually thinking about it. And it still didn`t explain how the neighbour using a welder would cause the problems in this thread, even with that sunglasses face thing. Strange things happen in electrical, but that would be an interesting one.

I have actually seen an RCD tripping in a house with the main switch off, but this house still had a neutral directly connected to earth in a socket, so enough current was diverting from the overhead neutral outside, in through the RCD, and to the earth wire at the neutral earth short, and onto the earth bar to earth rod. The house was not neutralised. If it had been, this probably would not have happened. But even as it was, the house in question still had an earth fault causing the tripping, which once removed, was fine. In this case, the load from other houses was contributing to the tripping. Mainly because of the small undersized overhead lines outside the houses.

Bruthal

THENORTHSIDER wrote: »

this isn't a fault situation so irrelavent:cool::cool:

Your making no sense now.

Bruthal

THENORTHSIDER wrote: »

possible that you may be inheriting fault from outside your board.

THENORTHSIDER wrote: »

this isn't a fault situation so irrelavent:cool::cool:

I see:rolleyes:

THENORTHSIDER

robbie7730 wrote: »

An earth fault may not take only the lowest impedence path, but any paths available.



As for the path of least resistance, when you turn on a shower (6 ohms) and a 60w bulb (880 ohms), which one is the path of least resistance? And which path does the current take? Not just the least resistance path anyway.
Most will take the lower impedence path alright, but it still takes any open to it.

Irrelavent as this isn't a fault situation. Whilst I think we have gone way off the problem here its ok to say a TN-C system USUALLY eliminates this but has the OP stated what type of supply he has

Bruthal

Maybe you meant my item about the shower and the bulb was not a fault situation so its irrevelent. But its not really. A fault current flows through all paths open to it, not just the lowest impedence one.

But you said that in refererence to saying next door might have been causing it. So, explain how a fault next door would trip an RCD in the Op`s house here. Exactly how it would happen, not just that phrase, about fault current taking the path of least resistance as an explanation.

Bruthal

THENORTHSIDER wrote: »

Irrelavent as this isn't a fault situation. Whilst I think we have gone way off the problem here its ok to say a TN-C system USUALLY eliminates this but has the OP stated what type of supply he has

Makes no difference what setup he has really with reference to a fault next door. The OP`s RCD is unlikely to trip if there are no faults in his own installation downstream of the RCD. My mention of the neutralised setup was to show current can be diverted into a fault downstream of the RCD. But it was not diverting fault current in, just the normal neutral current on the overhead line outside. How can earth fault current next door cause the RCD to trip in this case here if this installation has no fault?


In reality, the problem in this situation may well be a double fault. This RCD has too many circuits on it in my opinion, and it was another 2 fellas mentioned that earlier in the thread also, and i would listen to their opinions. So it may well be tripping due to accumulation of small leakages.

But the sockets going off and back on themselves is also happening. How is that?

Bruthal

Anyway, if we are gone away from the problem, here it is.

Sockets go off and back on themselves sometimes.

RCD sometimes trips.

So, faulty RCD possible, with bad contact(s) in it too.

Neutral earth fault in a socket circuit tripping the RCD, and also a loose connection causing the intermittent on/off of socket circuits. Possibly even a live earth problem, but that would usually trip the MCB also.

Or too many circuits on a single RCD, causing accumulated leakages combining enough to trip the RCD depending on whats running at any time, and a loose/bad connection.

You seem to rule out loose connection NORTHSIDER. But i would think it possible, simply because its obviously a possibility.

The RCD maybe getting replaced will fix all problems, and make it look like the loose or bad contact/connection was not part of it.

But i cant think of many causes for circuits going on and off and back on themselves beisdes connection or bad contact problems. Maybe you can?

THENORTHSIDER

Any developments

M cebee

i was waiting on you

to come back from the library with the solution

Bruthal

M cebee wrote: »

i was waiting on you

to come back from the library with the solution

Blowheads

Hi all, many thanks for replies. Intermittent fault still occuring, last night at 3am so could really rule out the neighbour welding! Could anyone recommend a sparks on galway that could cure this?

Blowheads

Hi all, many thanks for replies. Intermittent fault still occuring, last night at 3am so could really rule out the neighbour welding! Could anyone recommend a sparks on galway that could cure this?

THENORTHSIDER

not related to my welding neighbour then.

Am waiting for the return of 'Electrical Principles' in the Library :rolleyes: :rolleyes: :rolleyes:

Bruthal

Well im a carpenter but have worked around sparks a lot, ye pick up a few things about it along the way.

Blowheads

just one to close this off.

Strange as it seems we replaced the iron and the issue disappeared. I didnt understand how when it is switched off but still plugged in it could be causing this issue

Irish Steve

If it's a steam iron, a minor leak from the water tank running down on to internal connections could have produced a neutral to earth short, which will take out the trip even if there's no power on the circuit. Seen similar happen before when neutral and earth touch when replacing a faulty socket, even though the RCB is off on the circuit, the trip is doing the job it's there for.