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.

 

[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!!