New Consumer Unit Installation - L&N Reverse at the sockets

[Vol]

Hi there, I'm a newbie to the forum. I'm an ordinary senior citizen householder but while not an electrician, I do take notice and read up on all the stuff the electricians are doing in my house. I have just had a modern, metal consumer unit installed after the removal of the old traditional fuse box. The installation went pretty well with very few curses! Given the old wiring in the house, everyone was pleasantly surprised when both RCDs stayed good and the supply uninterrupted.
As a final check before leaving, the electrician inserted a socket tester. In every location tried, the socket tester showed L&N Reverse. I bought s socket tester and confirm the same readings: L&N Reverse. I haven't checked every single socket but that is the pattern.
One problem is that I have no way of telling if the old fuse box situation would have given the same L&N Reverse readings, ie did the electrician change anything or just carry on an existing (hidden) error?
Firstly, is this in any way a dangerous situation given the RCDs are quite happy? If dangerous, what should be done immediately?
Secondly, how could this reversal have occurred? The electrician simply reinserted the live and neutral cables appropriately as they were removed. The meter tails were changed cos the existing were only 16mm. Could the tails have been reversed somehow?
Anything else you guys can suggest?
Thanks for reading the newbie panic post! I would appreciate any input, thanks..

 

[telectrix]

could be tails reversed, incorrect connections in CU. get the electrician back immediately. how he could install a CU and leave the installation in that state, buggers belief. has he provided you with an installation certificate?

 

[mattg4321]

'Electrician' really should have known RCD's wouldn't cause a problem before he turned the installation back on. Sounds like not a lot of testing has been carried out here.

Would be interested to see the installation certificate (not likely I know). Was it Dave from the pub who fitted the new CU and whoever it was do they own the proper test equipment or was one of these used?

 

[Vol]

Hi telectrix, thanks for your quick comments. The electrician is coming back indeed and he will try to resolve the issue. On the day, he was flummoxed about the reasons why but as the RCDs were working well, he felt it safe to go (I knew in advance he had an unbreakable appointment later and to be honest, I agreed it seemed OK - which it has proved to be, so far). I am still awaiting the installation certificate, which has been promised.
It's odd, looking at the words it might seem that the electrician was a bit of a cowboy, I thought far from it. he was very conscientious it seemed to me. And the safe RCD situation seemed to trump all?

 

[Bobster]

Has he given you any form of certificate?

What testing did he undertake, as just plugging one of those testers in means little to nothing on whether the circuit is safe to energise.

He may have been a very friendly guy, but if you've not received certification and the electrician has not notified building control. You could have been left with a potentially unsafe install and find problems if you ever come to sell the house.

 

[Vol]

Hi mattg4321, no it wasn't Dave from the pub . s far as I am aware electricians don't have a similar scheme to the Gas Safe scheme when I can look up and check the credentials of a self-declared "electrician". Please let me know if there is such a scheme and I would use it.
The questions in my post were the most important bits. The key question was "is the situation dangerous and if so, what has to be done immediately". Any advice on that? The second question was about how it could have occurred?
Thanks for the input.

 

[streamer]

He should not have left it like that. Out of interest, what make is the new consumer unit?

 

[Ian1981]

Hi telectrix, thanks for your quick comments. The electrician is coming back indeed and he will try to resolve the issue. On the day, he was flummoxed about the reasons why but as the RCDs were working well, he felt it safe to go (I knew in advance he had an unbreakable appointment later and to be honest, I agreed it seemed OK - which it has proved to be, so far). I am still awaiting the installation certificate, which has been promised.
It's odd, looking at the words it might seem that the electrician was a bit of a cowboy, I thought far from it. he was very conscientious it seemed to me. And the safe RCD situation seemed to trump all?

Just because the rcd does not trip doesn't mean its safe in the terms you think it is, as highlighted by cross polarity at the socket outlets.
Polarity is a test done before the installation is energised, even a basic check with a 2 pole voltage tester at the incoming tails would have gave an indication as would a ze test.
I would check the tails coming into the meter from the cut out as well.
At the meter terminals it should be left to right
L N N L

 

[Vol]

Hi Rob, thanks. The very reason I am asking these questions on this forum is because I am aware already of the potential ramifications of a dodgy installation. Everyone seems focused on questioning the parentage of the electrical installer (and by implication, my own sanity for contracting with him in the first place), whereas what I really really want to know if the L&N Reversal is (actually and actively) dangerous and what to do if it is. Secondly, I would like to know how the problem might have arisen (and thus how it may be resolved) and thus be better informed when that, or another more like, electrician comes back to put things right.
I take your point about these little plug in devices. There should have been a more systematic testing of the circuit. But honestly,
I felt secure with the safe operating presence of the RCDs which I understood rightly or wrongly was one of the fundamental bases of the most recent code.
Thanks again for your input.

 

[tomspark93]

Hi mattg4321, no it wasn't Dave from the pub . s far as I am aware electricians don't have a similar scheme to the Gas Safe scheme when I can look up and check the credentials of a self-declared "electrician". Please let me know if there is such a scheme and I would use it.
The questions in my post were the most important bits. The key question was "is the situation dangerous and if so, what has to be done immediately". Any advice on that? The second question was about how it could have occurred?
Thanks for the input.

A Consumer unit change falls under "notifiable work" under Part P of the building regs. You can download a copy of this online which would make it clearer. He may have not got round to this yet as with the certificate. I usually issue certs within a week of completion.

The simple fact is that the reversed polarity that has been discovered should have really been found and rectified before he left. This would have shown up if he tested properly. If one point is showing L&N Reverse then it would suggest it's local to that point. If it's all of them then i'd hazard a guess that the reverse is at the board end which is then effecting the rest of the circuit.

 

[streamer]

A Consumer unit change falls under "notifiable work" under Part P of the building regs.

Part P doesn't apply in Scotland, we have our own building regs just to confuse matters!

 

[ImpededLoop]

The questions in my post were the most important bits. The key question was "is the situation dangerous and if so, what has to be done immediately". Any advice on that? The second question was about how it could have occurred?
Thanks for the input.

It is potentially dangerous and despite the pressing appointment it should have been rectified before the electrician left.

Were all of the circuits (lights, immersion, cooker etc) tested? What did the tester look like that he used?

We all have bad days, but I'm surprised that the problem is proving difficult to diagnose. I would seriously consider getting a second opinion.

 

[streamer]

In Scotland you could check if he is a member of Select or NICEIC. However, as has been discussed on here before, membership of these bodies doesn't ultimately prove the competence of the electrician. Nor does non membership prove they are not competent!

 

[tomspark93]

Part P doesn't apply in Scotland, we have our own building regs just to confuse matters!

Good point! didn't see that the ops from Scotland

 

[Vol]

Wow, I'm so impressed and grateful for the comments and advice! (NB I found myself sounding a bit defensive in my last posts but I'm not really.)
The consumer unit is a BG 16-Way Dual RCD Metal Consumer Unit & 12 MCBs sourced from Screwfix. It seems to have a decent enough reputation and seemingly ticks all the boxes.
If Part P doesn't apply in Scotland (where I am located), is the work there still notifiable in some other way?
I know it is almost impossible for qualified electricians to say, yeah, go on, it's probably safe. However, is there any substantial reason why my usual electrical load through fridges, washing machine (cool washes only), dishwasher (wash programmes only, no drying), TV etc should not continue over the weekend? If I cannot find an electrician to come out over the weekend, then it would be first thing next week. Does that timescale sound OK?
Thanks again, you've been very helpful.

 

[Rpa07]

Previous post #8 referencing polarity testing is the information you need to take to the electrician when he returns.
Polarity is there for a reason - one being that a single pole switch on a socket or such like will open the line conductor and not the neutral which can have And can lead to other dangerous issues so basically it's got to be right otherwise it's wrong - hope it get sorted quickly.

 

[Des 56]

A live-neutral reverse has the potential to cause harm
In the case of a light,a person could insert a lamp,unknown to the person (because of the reversal) the neutral of that light will be live and could cause injury
A appliance left plugged in will also have the neutral connections live whether its switched off or not
It is a potentially dangerous fault and needs rectifying

 

[Octopus]

One of the VERY first steps is to CONFIRM polarity and earthing on the supply to the main switch.... so this must have been missed... so any certificate can be viewed with suspicion.

As for the RCD .... most don't care which way round the L&N are - all they do is monitor the "balance" - so again if the so called spark doesn't understand this ......

Have you paid him?

 

[Ian1981]

how did the electrician test?
Did he just plug his radio in?
Sorry re read the original op.
He even identified L-N reverse and then left without identifying the problem!?

 

[Des 56]

What prompted you to go out and buy a socket tester thing
I ask because,it seems a unusual action for a customer,seems to be a needless expense in most circumstances as well