No Neutral problem

[John Lehman]

I have a house which has been wired (5 years ago) using radial circuits. Recently an entire circuit of plug sockets has stopped working, but all other circuits (whether they be lighting or socket circuits) continue to work. I bought a Circuit testing plug which has come up with "No Neutral". I have looked at all of the sockets on the circuit and I have found no scorch marks and they all appear to be wired correctly and securely. I am at a loss as to what else the problem could be. Could you help with suggestions of the possible fault or ways of testing for particular issues,

 

[bluetobits]

If none of the sockets on this particular circuit are working, it is likely a problem at the source. ie the consumer unit. if you are going to investigate, isolate the whole board first. 

 

[Andy™]

faults can also be at a point that works

 

[Doc Hudson]

Welcome to the forum, the circuit tester plug you mention has very limited practical use for proper fault finding. I would suggest that this problem needs to be tested on a dead circuit with a meter that can read continuity to trace each of the legs of the circuit from the fuse box to the furthest point of the circuit. I would be a bit concerned if a circuit that was wired only five years ago has failed (probably due to a lose termination somewhere) so soon. Was this a reputable electrical contractor or a DIY/friend doing a cheap job? If it was a proper qualified electrician you should have a copy of the 3-page Electrical installation certificate which will have on it the continuity test reading along the live and earth for this circuit. the neutral and earth continuity should give the same values on a radial circuit . so by measuring at each of the sockets you should be able to verify that there are no other potential lose connections that could cause further problems.   Are there any junction boxes on the circuit where the radial branches?

Doc H.

 

[Evans Electric]

The fault is probably at the consumer unit as said above .

We have to be careful when giving any advice that could prove dangerous to an unskilled person ...which is probably why the other members have declined to offer further advice .  

If your house was rewired 5 years ago you may have a separate Main Switch ,  would you like to take a look and tell us if there is a Main Switch in your meter tails BEFORE  the consumer unit .   

 

[John Lehman]

Yes there is a main switch before the consumer unit, and in reply to the previous comment it was a reputable contractor that fitted the electrics.

 

[ProDave]

How do you know it is a radial not a ring circuit?

I take it you have not done any wiring checks, just plugged in a tester and looked for obvious scorch marks.

you won't find the fault without unscrewing the sockets from the wall and / or looking inside the consumer unit.  If you are not competent to do that yourself, get a local electrician in. It will probably turn out to be a very simple and quick fault to find and should not cost you much if it's a reputable electrician who charged a fair rate.
 

 

[Evans Electric]

Then in that case you can safely isolate the consumer with that switch ...remove cover and check for a loose connection on the neutral bar . 

If  you have RCBOs in there you will need to check the connections at the appropriate device .  ( RCBOs  are like MCBs but have a test button on them) 

Make sure you switch OFF that isolator ...or death will follow ....you will go to that unknown land from which none have returned .

If in any doubt , employ a qualified Electrician .  

 

[Murdoch]

whats the rating of the RCBO?

 

[John Lehman]

Thanks for the replies, to answer a number of the questions

1) We owned the house when the wiring was done, it was a complete renovation (still on-going!!!) so we know that the circuits were Radial as that was what was specified

2) I have taken off each faceplate on the affected circuit, all neutrals appear securely connected and there are no signs of scorch marks e.t.c that may indicate a bigger problem

3) I have changed the faceplate on the first socket on the circuit just in case it was a problem with the faceplate (long shot but the faceplate cost buttons) with no success.

4) The only action I haven't taken is looking in the consumer unit which will be my next port of call

 

[Murdoch]

Somebody with a MFT could have investigated this in about 15 minutes ...... and almost certainly identified the cause....

 

[Tony S]

Murdoch has it right, get an electrician with experience of testing procedures. Far quicker and far, far safer for your family.

 

[Doc Hudson]

Thanks for the replies, to answer a number of the questions

1) We owned the house when the wiring was done, it was a complete renovation (still on-going!!!) so we know that the circuits were Radial as that was what was specified

2) I have taken off each faceplate on the affected circuit, all neutrals appear securely connected and there are no signs of scorch marks e.t.c that may indicate a bigger problem

3) I have changed the faceplate on the first socket on the circuit just in case it was a problem with the faceplate (long shot but the faceplate cost buttons) with no success.

4) The only action I haven't taken is looking in the consumer unit which will be my next port of call

Why were you looking for scorch marks? is there something you have not told us about problems with fuses blowing? Replacing a face place was never going to be a long shot, as from the symptoms you have described it could never be a possible cure. You are doing pretty much all of the wrong things in the wrong order without any appropriate test equipment. A continuity tester and an adapter plug with test lead sockets would have narrowed the possible causes down within a few minutes without opening up any sockets, just the correct first port of at the fuse box. What alterations have you done to the circuit since it was rewired?  How many outlets are there on the circuit?

Doc H

 

[John Lehman]

There have been no problems to date, I only mentioned the scorch marks just to point out that the faceplates looked in good order and that there were no signs of any obvious major issues.

No changes have been made to the installation since install, we have 5 double sockets on the radial circuit which are lightly used at best, one gets a iron plugged in 2 or 3 times a week.

What I am gathering from the posts so far is that as it is a radial circuit and as all of the sockets have gone it is likely to be an issue with the consumer unit.

 

[Slowhand]

The last 2 faults l investigated had the same problem.

The neutral had completely burned off in the consumer unit.

Probably due to the termination not being tightened enough.

In both cases the plastic of the consumer unit had started to melt and the terminal screw was welded to the neutral bar.

If you find this is the case you'll need to get a qualified person in to test the circuit for insulation resistance etc.

Maybe give the unit a good check for overheating and tighten up anything else that may be loose.

If it was only installed 5 years ago try getting the person who installed it back to look at it.

What date does the sticker on the C/U give for the next inspection?

Any decent spark would guarantee their work for longer than 5 years.

 

[ProDave]

Not being tightened enough is as far as I am concerned a convenient place to lay the blame anywhere but on the manufacturer.  Quite frankly in many respects the design of modern CU's is appalling. and the "solution" to overheating neutral bars was put them inside a tin box to stop the spread of fire, rather than look at the problem and eliminate it.

That is why, when I had a CU change to do earier this year (because of this same issue) and knowing it had an electric boiler that drew 50A, I wanted a better, properly engineered solution and ended up with a CU that SBS Dave put together that had neutral bars with two screws per termination, like they used to be when things were done properly.

 

 

[Andy™]

The neutral had completely burned off in the consumer unit.

you mean like this?



and no idea how that highly flammable wood and not bomb proof metal CU didnt burn the place down...

 

[Slowhand]

you mean like this?



and no idea how that highly flammable wood and not bomb proof metal CU didnt burn the place down...

Yes exactly like that.

In the last case the neutral had burned a hole in the busbar feeding the rcd.

I'll have to work out how to get pics from my phone onto here.

 

[Slowhand]

Not being tightened enough is as far as I am concerned a convenient place to lay the blame anywhere but on the manufacturer.  Quite frankly in many respects the design of modern CU's is appalling. and the "solution" to overheating neutral bars was put them inside a tin box to stop the spread of fire, rather than look at the problem and eliminate it.

That is why, when I had a CU change to do earier this year (because of this same issue) and knowing it had an electric boiler that drew 50A, I wanted a better, properly engineered solution and ended up with a CU that SBS Dave put together that had neutral bars with two screws per termination, like they used to be when things were done properly.

 

It doesn't matter how many screws there are if none of them are tightened enough.

See photo above.

 

[Murdoch]

I'll have to work out how to get pics from my phone onto here.

Drop box to cloud, get pickies onto laptop, upload onto forum.....

thats what I do!