Problem this afternoon

[uksparks]

Hi,

Got called to a customer today, background is he has been doing some DIY... he had replaced a load of light fittings and plug sockets, he said we extended this one here and burried it in the wall etc... found one twisted together with tape, no connectors etc... anyway..

The problem is, since yesterday, he said the plugs downstairs don't work... hmmm

I plugged the socket tested in, beep beep beep beep beep, Earth and Live Reverse.... so i go to another, and get the same, then go to another, and its already beeping at me without switching the switch on, its a Fluke socket tester, first two are lit up, then switch it on then its just the first one so suggest Live earth reverse.

I then get the MFT out, plug it in at a socket,

Line to Neutral = 5.5v
Line to Earth = 230v
Neutral to Earth = 230v

Hmm, that's not right...

I pulled off all the face plates down stairs that I could that appears to be on that circuit one at a time thinking ill find the problem, but nope, nothing, all seemed in order (a mess but in the right holes). They said they did not extend or chop any circuits on the plugs, only the lights (they work fine).

Oh its a radial by the way.

So then the lounge, I took the faceplate off, left all conductors hanging (terminated in wagos) turned back on, same problem on sockets, but the ones he had changed were all dead, so im thinking must be somewhere else, put it back together.

Looked at the consumer unit, dual split board, a mess, blatant cowboy who fitted it, everything in the wrong places etc, but anyway, RCD protected. So the circuit was holding fine, as was the RCD.

I put a jumper between Line and Earth and then went round the sockets to get an R1+R2, all seemed pretty much in order, went round everything I could find, all seemed to be ok.

Then hooked Line to Neutral, went round the sockets, not a bloody sausage, nothing, not on any socket anywhere, nothing hooked off the circuit.

Then hooked Neutral to Earth and got a reading on everything.

So then I thought, well everything appears to be in the correct places so what the hells going on... I said it Friday night, I want to go home now thanks, and am going back next Tuesday and have left the circuit off.

My next step is to remove all faceplates on the circuit, so perhaps 15 say, then try to connect one at a time and see what happens.

Has anyone got a better suggestion as ill be honest, im stumped on this, I normally find these things quick and move on, but I spent 2.5 hours then this evening and couldn't work it out.

He assures me he has only changed Faceplates, only 4 of them down stairs in the lounge, you could see they were new. He has not touched anything else on the plug circuit.

 

[MDJ]

What is a plug circuit?

 

[nickblake]

Hi,

Got called to a customer today, background is he has been doing some DIY... he had replaced a load of light fittings and plug sockets, he said we extended this one here and burried it in the wall etc... found one twisted together with tape, no connectors etc... anyway..

The problem is, since yesterday, he said the plugs downstairs don't work... hmmm

I plugged the socket tested in, beep beep beep beep beep, Earth and Live Reverse.... so i go to another, and get the same, then go to another, and its already beeping at me without switching the switch on, its a Fluke socket tester, first two are lit up, then switch it on then its just the first one so suggest Live earth reverse.

I then get the MFT out, plug it in at a socket,

Line to Neutral = 5.5v
Line to Earth = 230v
Neutral to Earth = 230v

Hmm, that's not right...

I pulled off all the face plates down stairs that I could that appears to be on that circuit one at a time thinking ill find the problem, but nope, nothing, all seemed in order (a mess but in the right holes). They said they did not extend or chop any circuits on the plugs, only the lights (they work fine).

Oh its a radial by the way.

So then the lounge, I took the faceplate off, left all conductors hanging (terminated in wagos) turned back on, same problem on sockets, but the ones he had changed were all dead, so im thinking must be somewhere else, put it back together.

Looked at the consumer unit, dual split board, a mess, blatant cowboy who fitted it, everything in the wrong places etc, but anyway, RCD protected. So the circuit was holding fine, as was the RCD.

I put a jumper between Line and Earth and then went round the sockets to get an R1+R2, all seemed pretty much in order, went round everything I could find, all seemed to be ok.

Then hooked Line to Neutral, went round the sockets, not a bloody sausage, nothing, not on any socket anywhere, nothing hooked off the circuit.

Then hooked Neutral to Earth and got a reading on everything.

So then I thought, well everything appears to be in the correct places so what the hells going on... I said it Friday night, I want to go home now thanks, and am going back next Tuesday and have left the circuit off.

My next step is to remove all faceplates on the circuit, so perhaps 15 say, then try to connect one at a time and see what happens.

Has anyone got a better suggestion as ill be honest, im stumped on this, I normally find these things quick and move on, but I spent 2.5 hours then this evening and couldn't work it out.

He assures me he has only changed Faceplates, only 4 of them down stairs in the lounge, you could see they were new. He has not touched anything else on the plug circuit.

There's your answer Earth to neutral 230 volts you've lost a neutral some where and confirms it with live earth reverse on a socket tester not an accurate means of testing

 

[Octopus]

I'd get your wander lead out and check the continuity of each core from the CU......

 

[R G]

I'd get your wander lead out and check the continuity of each core from the CU......

Thats the proper way to do it , rather than using R!+R2 method ,or your going to get confused ,,,

 

[Octopus]

I did just this last week ..... far easier to get to the bottom of the issue, especially on a radial!

 

[uksparks]

Well yes, ill be getting the wander lead out when I go back, I hadn't really got time to look to far into it as its Friday night and ive got better things to do live go on here LOL.

I will do as in post #4

Surely if you are getting 230v across Neutral and Earth, how can you have a lost neutral? Clearly there is one there as its got 230v across it.

Not only that you shouldn't get 230v across Neutral and Earth, so how do you explain that if the Neutral is lost?

Also, if you are saying its a lost neutral, how comes you don't have 230v from Line to Earth?

I tested this with my MFT to see, it clearly showed:

Line to Neutral = 5.5v
Line to Earth = 230v
Neutral to Earth = 230v

This is not readings from a socket tester. I only plugged the socket tester in to see if it was 'normal' so to speak. If you had no neutral you would not get 230v Neutral to Earth.

Am i being thick and missing the obvious or something?

 

[Plonker 3]

No there's 230 volts to earth, meaning the neutral is not returning to the DB and beyond. As others have said wander lead test every cable.

 

[jaypp]

Were your readings increasing from board as expected for radial?

 

[davesparks]

Remember the golden rule of fault finding: Don't trust what the customer tells you!

 

[uksparks]

Yes the readings we increasing as you would expect.

Dillb, you say its 230v to earth, I appreciate that, but if you are saying that the neutral is lost, i.e disconnected, broken, how can 230v go up the neutral and down the earth if its broken / disconnected somewhere?

Are you suggesting that the socket testing is wrong then? It clearly says the earth and line are reversed. Can you explain to me then how this is not the case?

I am trying to get my head around this in a logical manor but something inst clicking clearly.

 

[uksparks]

Remember the golden rule of fault finding: Don't trust what the customer tells you!

They all lie.

 

[Plonker 3]

Yes the readings we increasing as you would expect.

Dillb, you say its 230v to earth, I appreciate that, but if you are saying that the neutral is lost, i.e disconnected, broken, how can 230v go up the neutral and down the earth if its broken / disconnected somewhere?

Are you suggesting that the socket testing is wrong then? It clearly says the earth and line are reversed. Can you explain to me then how this is not the case?

I am trying to get my head around this in a logical manor but something inst clicking clearly.

There is obviously something plugged in that's not working, that puts voltage onto the neutral, which will then be shown on your tester.

 

[ipf]

First of all, check the neutral connection in the cu. Plug testers can be fooled.

Why do you get a belt from a disconnected neutral on a live circuit ?

 

[uksparks]

I'll go over Tuesday and sort it, Friday night is not the most ideal time to be fault finding. Something has clearly changed as he said he changed the 4 faceplates and then they wouldn't work... I'm not convinced.

enjoy your weekend.

 

[uksparks]

I unplugged everything and also switched all FCU's off by the way. It will probably be obvious to me when I go back.

 

[davesparks]

how can 230v go up the neutral and down the earth if its broken / disconnected somewhere?

230V doesn't go up or down anywhere, it exists at a point (any point) relative to another point.

Neutral is normally at 0 volts relative to earth ,ie. connected to earth, and live is at 230volts relative to neutral (and earth).

In your situation the connection to neutral has been broken at some point so everything which is the other side of the break will be effectively floating and not have any potential (voltage) relative to live or neutral. Except when a load is connected to the circuit, at which point the floating neutral wire becomes connected to live (via the load) and will therefore have a potential of 230volts relative to earth.

 

[jaypp]

and its already beeping at me without switching the switch on

are they only switching 1 pole? Also re DIY, explain to customer (tactfully) that the longer it takes, the more it costs and if he can remember seeing 'someone' doing j.b's etc and where, it will save £'s, then the canary will sing!

 

[uksparks]

Yes it must be so single pole. I cannot believe thT he only changed three faceplates, it's not possible to create this problem.

 

[uksparks]

230V doesn't go up or down anywhere, it exists at a point (any point) relative to another point.

Neutral is normally at 0 volts relative to earth ,ie. connected to earth, and live is at 230volts relative to neutral (and earth).

In your situation the connection to neutral has been broken at some point so everything which is the other side of the break will be effectively floating and not have any potential (voltage) relative to live or neutral. Except when a load is connected to the circuit, at which point the floating neutral wire becomes connected to live (via the load) and will therefore have a potential of 230volts relative to earth.

As everything was unplugged this is what is not helping, I'll let you know how I get on when I go back.

 

[davesparks]

are you sure everything is unplugged and disconnected from the circuit? If a diyer has been at large then there could be anything connected to that circuit including lights, showers, cookers, next doors cat etc.

And what are you using to measure the voltage? an AVI? if not then you may be chasing a ghost voltage.

 

[Richard3009]

Wander lead and methodically go down each core, the broken circuit has to show.

 

[davesparks]

Wander leads? testing each core? what is this?

1- Split the circuit in half, find which half contains the fault.
2- split the faulty half in half again and find which half contains the fault.
3- split the faulty half in half again and find which half contains the fault.
...........
hey presto! you've found the fault.

 

[Richard3009]

If any load has been tapped off the ring and you have a broken neutral this problem would appear, you need to find where the neutral is open circuit

 

[uksparks]

I am confident everything was unplugged, I went through very room myself and made sure. I used my Fluke MFT to measure the voltage and twiddled the thing to switch it between conductors etc.

I split the ring in one place and it knocked out the room he claimed to have been messing with, the problem was still there, so therefore the problem must be somewhere else, either it's a whopping coincidence that it's gone funny when he changed the faceplates, or he is not telling me something...

 

[uksparks]

I see what you mean now about the neutral being broken and voltage going through the line to neutral then to earth.

 

[basejumper31]

Reading the above.. holy hell, what am I getting into training for this profession!! lol. Joking, I enjoy the challenge, but, wow, I can kinda see why this takes many years to get proficient at!

Good luck when you go back on Tuesday. Also nice to see such an active and helpful community!

(UkSparks hope you don't mind this off-topic comment.. I will ofc delete if you do)

Have a great wkend everyone.

 

[Richard3009]

Wander leads? testing each core? what is this?

1- Split the circuit in half, find which half contains the fault.
2- split the faulty half in half again and find which half contains the fault.
3- split the faulty half in half again and find which half contains the fault.
...........
hey presto! you've found the fault.

Radial circuit don't split it, just run wander lead from CU to each N connection until you lose continuity, then try to figure out the physical routing of cables and hunt down the nasty connection junction box or connector block

 

[davesparks]

Radial circuit don't split it, just run wander lead from CU to each N connection until you lose continuity, then try to figure out the physical routing of cables and hunt down the nasty connection junction box or connector block

Why use a wander lead? you have all the conductors you need already installed in the circuit.

I was explaining the method of fault finding any standard circuit, be it ring or radial.

In this case you can quite easily test voltage at each socket and identify where the neutral becomes broken without use of either wander lead or splitting the circuit. Where it's good there will be negligible voltage between N and E and nominal 230V between L and N, where its bad there will be nominal 230V between N and E and negligible V between L and N.

 

[davesparks]

I see what you mean now about the neutral being broken and voltage going through the line to neutral then to earth.

I don't think you do, the voltage is not going through anything. Voltage is a measure of the electrical potential at a point, it doesn't travel anywhere.

I am constantly amazed at the number of people who struggle with this concept, everybody learns this stuff at school yet nobody seems to understand!

 

[Richard3009]

True various methods, I like dead circuits though, they tell the truth.

 

[uksparks]

I think either method is going to work, just need to get back to it to sort it now.

I did try continuity of neutral and line connected and got zilch at every socket... Pain in the ---.

Now I'm armed with a few ideas, I should be able to locate it without too many issues.

 

[uksparks]

I don't think you do, the voltage is not going through anything. Voltage is a measure of the electrical potential at a point, it doesn't travel anywhere.

I am constantly amazed at the number of people who struggle with this concept, everybody learns this stuff at school yet nobody seems to understand!

I do get it, I just don't explain myself that well, I know it's a difference in potential, and know it doesn't go up one way and down the other.

 

[Richard3009]

Take your time and don't panic, you can always rewire it :cyclist:

 

[Richard Burns]

I did try continuity of neutral and line connected and got zilch at every socket... Pain in the ---.

If you got no continuity on all sockets then this points to the problem being before the sockets, try testing from the first socket (if you can tell where it is) to the later sockets and if all is OK then the problem is between the first socket and the CU. It does not have to be where the work was done, circuits can fail anyway (but may have been helped along by DIY)

 

[Badged01]

Bit late on a Friday night and the old speckled has gone down great guns so I might not be thinking too straight in my analysis but based on what your saying I reckon you have a L and E reversal problem ........

I plugged the socket tested in, beep beep beep beep beep, Earth and Live Reverse....

Wouldn't trust them to tell you what the problem is, just that you've potentially got a problem! But hey it might be right this time ...

Line to Neutral = 5.5v
Line to Earth = 230v
Neutral to Earth = 230v

If you have no loads applied when doing the tests (i.e. no L to N connection) this is telling me your earth is at 230V and Live & Neutral are at 0V ..... maybe your socket tester isn't lying and the E and L are reversed! Why didnt the RCD 'pop' on the tests? If so on which one?

I pulled off all the face plates down stairs that I could that appears to be on that circuit one at a time thinking ill find the problem, but nope, nothing, all seemed in order (a mess but in the right holes).

If all the sockets are wired correctly then you've got a problem elsewhere in the circuit ..... starting to think you've got a junction box or something somewhere crossing over the polarity? Assuming its not at the CCU? Somewhere between the CCU and 1st socket?

the ones he had changed were all dead

Is that dead L-N, L-E and N-E? If just L to N then they will be if you do have a L and E reversal. If dead across everything then there must be a break in the live feed but this would effect all the sockets unless they are the end of the radial! The plot thickens .....

So the circuit was holding fine, as was the RCD.

Was the RCD holding with loads applied (and working!) at the sockets? If so you cant have a L to E cross-over so my theory disappears!. If the breaker holds you ain't got a L to N cross-over either at any point. Whatever it is, its consistent and not just a single problem!

put a jumper between Line and Earth and then went round the sockets to get an R1+R2, all seemed pretty much in order,

As in every single socket? If so then you ain't got any single L to E problems but you could have a total L to E reversal!

Then hooked Line to Neutral, went round the sockets, not a bloody sausage, nothing, not on any socket anywhere, nothing hooked off the circuit.

Nope you wont have if the whole circuit L and E have been reversed!

Then hooked Neutral to Earth and got a reading on everything.

Yep, you will have if the whole circuit L and E have been reversed

So then I thought, well everything appears to be in the correct places so what the hells going on...

They can't be for the results you've got, something is amiss somewhere in the circuit ... no sh*t Sherlock!

Does anything work when plugged in? If not you've got a L-E reversal, nothing will work! If it does work then I reckon you need to patent the circuit as you've discovered a new law to physics .....

 

[Engineer54]

I'll go over Tuesday and sort it, Friday night is not the most ideal time to be fault finding. Something has clearly changed as he said he changed the 4 faceplates and then they wouldn't work... I'm not convinced.

enjoy your weekend.

So you have left the customer without downstairs sockets until Tuesday?? Well your customer won't be enjoying their weekend then, will they!!

Not exactly the best approach for customer care, and i wouldn't blame the customer at all, if he called in another electrician to sort the problem out....

Fault finding on a radial socket circuit is a doddle, a methodical approach would have found the problem within the hour...

 

[Richard3009]

On a Friday night at beer o clock I would leave the whole house switched off. :driving:

 

[Silly Sausage]

So you have left the customer without downstairs sockets until Tuesday?? Well your customer won't be enjoying their weekend then, will they!!

Well, it was the householder mincing around with the electrics to begin with, so, tough -------!

 

[davesparks]

True various methods, I like dead circuits though, they tell the truth.

You what now? I don't understand?

What truth do dead circuits tell? and what untruths do live circuits tell?

 

[uksparks]

Thanks Badged01, I'd nicely reply to your comments like you have but on the iPad so it's not so quick and easy.

Nothing on that circuit works when plugged in due to 0v on L-N

I am confident everything was unplugged and no loads

The breaker didn't trip

The rcd didn't trip

Both were holding fine.

I got an acceptable R1 + R2 at each socket which suggests which suggests line and earth are in those two places, but not the right way round.

If they were the wrong way round, because they had been switched somewhere near the origin lets say, then that would explain why by line to neutral readings were duff as it was really neutral to earth.

I am still confident that they have been switched, I know socket testers ate not the best gadget, but there mus be ome truth it in, isn't there? Like I say I did plug the MFT in to check properly.

 

[davesparks]

On a Friday night at beer o clock I would leave the whole house switched off. :driving:

I wouldn't!

 

[uksparks]

So you have left the customer without downstairs sockets until Tuesday?? Well your customer won't be enjoying their weekend then, will they!!

Not exactly the best approach for customer care, and i wouldn't blame the customer at all, if he called in another electrician to sort the problem out....

Fault finding on a radial socket circuit is a doddle, a methodical approach would have found the problem within the hour...

He said it had been like it for two days and he had extensions running from upstairs, he was happy to wait, unfortunately for him I am tied up until Tuesday afternoon. It is a doddle usually, but when mr DIY is not telling you the truth it makes things difficult.

 

[davesparks]

I am still confident that they have been switched, I know socket testers ate not the best gadget, but there mus be ome truth it in, isn't there? Like I say I did plug the MFT in to check properly.

Not necessarily, ive got a socket tester that regularly reports a missing neutral on perfectly OK sockets, but since I only use for the noise to give an indication of when I've pulled the right fuse i'm not going to replace it any time soon.

 

[Engineer54]

Well, it was the householder mincing around with the electrics to begin with, so, tough -------!

And now he is ''Paying'' for a professional to sort his blunders out, except it's not being sorted out is it?? lol!!

 

[davesparks]

Yeah it is being sorted out, by those of us daft enough to help on here!

Do you think he's charging for the time spent here researching basic fault finding?

 

[uksparks]

Well, it was the householder mincing around with the electrics to begin with, so, tough -------!

My thoughts entirely, it was commical actually, his mate comes in from over the road who has been helping him this week. He has moved light switches and extended the cables etc, extended the plug circuit with the problem, he did show me the joint which I redid as it was twisted ends with tape...

He had cut the old boiler thermostat off the wall as he said it was for the old boiler and not used so the wire was dead... He buried the cut end in the wall. He showed me where, I said so why is my volt stick (stop laughing) glowing red then when it goes near your dead cable? Pulled it out the other side of the wall, it was live so made safe.

Its a DIY mess, it's probably been like this for a week.

 

[davesparks]

A whole week, blimey!

there's houses out there that have been like it for a whole decade or more!

 

[uksparks]

And now he is ''Paying'' for a professional to sort his blunders out, except it's not being sorted out is it?? lol!!

It will be sorted, but as it was early Friday evening and had plans, I really didn't want to be there and would rather arrange to look at it properly with more time. He rang me to say he had changed a plug socket and now it's not working, I only went because it sounded like a quick job...

 

[uksparks]

A whole week, blimey!

there's houses out there that have been like it for a whole decade or more!

I know how to find faults and don't usually have problems, just this one seems a little more irritating and probably not being told the truth from mr DIY doesn't help.