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

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Vol sorry to see that you feel you have been vilified on this forum, but the truth is there have and will be hundreds of similar threads, where people have purported to have electric work carried out by electricians, when in fact they have carried out the work themselves and something has gone wrong.

Lets give you the benefit of doubt, and accept you have been subjected to poor electrical experience.

Without going through everything again, I think davesparks #98, encapsulates what most have said. The socket testers you speak of are not, test equipment per say, but are just a piece of equipment used on the completion of work, as a kind of double check on everything else that has been tested. Indeed, if the correct tests have been carried out, there is perhaps little use for them.

So therefore to 'discover' this fault with such a socket tester, at this stage is somewhat surprising. As regards disagreement between members, the wiring regulations BS7671, is a very large document, with vague sounding definitions & recommendations, so its not a surprise that we cannot all agree on the interpretation of every regulation.

Hope all go's well tomorrow, and let us know how you get on.

Kind Regards
 
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Hi Vol thanks for the reply. You did say in post no. 56
Vol said:
If you have a real suspicion of something germane, then speak up and give your evidence.
Click to expand...
I offered something germane to the conversation. At no point have I stated or inferred you have lied. But if the cap fits then indeed wear it. In fact I took pains in stating I accepted this may be something beyond your ken. But no matter I have had worse insults on this forum and elsewhere. There is no evidence as there is no accusation. I will stand by my assertion that something is missing. You have been told the cause may be on the DNO side as opposed to the electricians. I would not venture opinion on such a set of vague facts without personally inspecting the installation myself (which I guess will not happen til hell freezes over!) However the fact you are left in this situation is a breach of the law. That is incontravertible. I suggest you take heed of the cautions you have been offered.
As regard differing opinions...you never heard your father debate engineering principles? Clergy debating interpretation of scriptures, politicians policies on and on. It is this very debate that reveals what is commonly accepted arriving at consensus opinion. We are not all automatons who regurgitate the "law" we are thinkers and like to mull on the possibilities. If the kitchen is too hot....
As regards socket testers, would you use a bicycle pump to pump up your car tire?
 
Well this really has turned into an epic, one that I wasn't going to get involved in.
But after reading Vols rant, there are a few things that come to mind.

@Vol:
1) Nobody said that we were infallible & don't make mistakes but in our industry, Your "Electrician" leaving you in the situation he has: To us that doesn't class as a mistake, it classes as sheer bloody incompetence.

2) I believe you said your electrician is NIC registered, you could have checked with them.

3) Don't remember you mentioning before this, that a scot power engineer was also on site.

4) Your "Electrician" should have tested prior to the CU change without question.

5) A socket tester provides a quick test only, Proper testing must be carried out using the Correct Calibrated test equipment, otherwise you don't know things are safe & whatever certificate he provides is worthless.

6) You say the "Electrician" cleared his diary as soon as you informed him of your concerns, Yet by your initial statement he already knew about the problem, and was quite happy to walk away and leave you to it.

7) If as you say, your worried you may have a supply problem, then take the advice you've already been given, including by a Scot power engineer. Put in an Emergency call to Scott power.

8) You think your "Electrician" is giving a fair response under the circumstances, Sorry but we'd all disagree with that.

You wonder why we're getting sceptical, maybe it's that there seem to be inconsistencies in the story, even for a householder that likes to keep informed you appear to know too much regarding the 17th & exactly what the pertinent regs are, on several occasions you've been asked to provide a picture of what has been installed , on each occasion you've chosen to ignore the requests.

As for myself, I think your rant shows total Disrespect to the Qualified & Highly experienced Electricians on this forum, that Freely gave their time to try to advise you.

OK that's it, I'm done & out of this farce.

Dan: If you don't find the above in keeping with Forum rules, I apologise.
 
Last edited by a moderator:
In all fairness chaps the OP has consistently denied this allegation. Judging from afar is somewhat thwart with danger.

Whilst I have had my suspicions, we should give the OP the benefit of doubt. Hopefully the fault, if it does exist, will be rectified tomorrow, which at the end of the day is the major concern.

Lets look forward to the OP reporting back, with the result. :)
 
@Vol

You can get basic checks on an electrician using the Registered Competent Scheme - Electrical here:-

Home - http://www.electricalcompetentperson.co.uk/

This will tell you if the person you are about to employ is a member of one of the competent persons schemes. As you've pointed it, whether these schemes adequately serve their purpose is open to debate, but it is a good start as they do require you to prove you have certain qualifications, certain insurances etc. in place. I have photographic ID provided by my scheme and if you were my customer I would happily provide you with the details you need to go off and confirm what I'm telling you.

However, in the case of electricians, you don't need to be a member of these schemes to meet your legal obligations under the building regulations and this is where it starts to get a bit tricky. I can't say for Scotland, but in England and Wales if I want to change a consumer unit I either be part of a scheme and notify the work myself via my scheme or I pay LABC and submit an application to carry out the work and they will inspect it.

So the reality is, you could notify building control, pay their fees, change the consumer unit yourself and they'll arrange for it to be inspected/tested to ensure compliance with BS7671 and the building regulations (how good a job they do is probably another subject which is open for debate). The unfortunate thing is there is nothing stopping an unscrupulous cowboy not telling you what his obligations are, and all too often this works because home owners are, in my experience, woefully uneducated when it comes to the requirements of building regulation and electrical certification.

In terms of finding this fault, there are various stages of testing that should be carried out as has been stated previously. There are the dead tests which serve to prove the continuity of the circuits and that their polarity is correct. They also aim to check that the cabling is in good condition and that no faults exist on the fixed installation that could trip the RCDs. If this isn't done, how can you know whether it's the fixed installation that is at fault or a piece of equipment connected to it?

The fact that there was surprise when the RCDs didn't trip suggests that some (or all) of these tests were not carried out. This suggests a lack of something in the person carrying out the work. Knowledge, equipment, morals, it's difficult to say.

In terms of the reversed polarity, this should have been identified and corrected BEFORE the main switch was turned on. A socket tester is the last piece of test equipment I use and serves as a verification only that power is on and there are no obvious faults at the socket outlet to which it is connected. An approved voltage indicator is the tool for detecting polarity issues at the supply and as I say, this should have been done before that main switch was flicked to ON.

We disagree on things (including how you should proceed) because we all have different views and experiences and as has already been highlighted the wiring regulations create grey areas which are open to interpretation. However we are all agreed that this is a dangerous situation that should have been resolved already and that you should minimise your use of the installation.

We are not immune from making mistakes and I don't believe anyone has suggested we are infallible, we are after all only human, but testing procedures are down in black and white and are there for a reason... the safety of our customers and the installations we work on. Not following them is an act of gross negligence that can result in the kind of situation and danger you are now subjected to.

These things will make us question the competence and ethical standards of the person carrying out the work because for us, it is incomprehensible that someone would leave a customer site knowing the risks this fault presents and this unfortunately is human nature because we invariably judge others by the standards we set ourselves.

But, they will also make us question the the validity of the information provided and whether in fact a spark was involved at all, because quite simply I think deep down we would all like to believe that someone who calls themselves an electrician could not be guilty of such gross negligence and have such a cavalier attitude to electrical safety that they just up and leave for another appointment knowing this fault existed. It's so fundamentally wrong that we have trouble wrapping our heads around the fact someone could do it (I'm not ashamed to admit I have also wondered whether we've had the truth, the whole truth and nothing but the truth), and I'd go so far as to say that if I got called in to clean up after such an event I'd be wanting full details of the original spark so I could report them to their scheme or trading standards. That's how bad this is and as I say, I think we just have trouble accepting the fact that someone trading as an electrician could do it because it goes against the grain so fundamentally we struggle to accept the facts.

With regards to missing an opportunity for the consumer unit to protect against reverse polarity, we are there to protect against reverse polarity. The checks we are supposed to carry out are there for this exact reason.

Please come back and let us know the outcome of tomorrow.
 
The one thing that doesn't add up to me - assuming the CU change was carried out by a qualified sparks with the proper test equipment- is the fact that a reverse polarity situation that sounds like it affects a majority (if not all) circuits would've taken seconds to diagnose and highly likely a couple of minutes or less to find the cause. Surely his 'pressing arrangement' can have waited another 90 seconds.
 
mattg4321 said:
The one thing that doesn't add up to me - assuming the CU change was carried out by a qualified sparks with the proper test equipment- is the fact that a reverse polarity situation that sounds like it affects a majority (if not all) circuits would've taken seconds to diagnose and highly likely a couple of minutes or less to find the cause. Surely his 'pressing arrangement' can have waited another 90 seconds.
Click to expand...
He got paid and did one a bit quick
 
SparkyChick said:
@Vol

You can get basic checks on an electrician using the Registered Competent Scheme - Electrical here:-

Home - http://www.electricalcompetentperson.co.uk/

This will tell you if the person you are about to employ is a member of one of the competent persons schemes. As you've pointed it, whether these schemes adequately serve their purpose is open to debate, but it is a good start as they do require you to prove you have certain qualifications, certain insurances etc. in place. I have photographic ID provided by my scheme and if you were my customer I would happily provide you with the details you need to go off and confirm what I'm telling you.

However, in the case of electricians, you don't need to be a member of these schemes to meet your legal obligations under the building regulations and this is where it starts to get a bit tricky. I can't say for Scotland, but in England and Wales if I want to change a consumer unit I either be part of a scheme and notify the work myself via my scheme or I pay LABC and submit an application to carry out the work and they will inspect it.

So the reality is, you could notify building control, pay their fees, change the consumer unit yourself and they'll arrange for it to be inspected/tested to ensure compliance with BS7671 and the building regulations (how good a job they do is probably another subject which is open for debate). The unfortunate thing is there is nothing stopping an unscrupulous cowboy not telling you what his obligations are, and all too often this works because home owners are, in my experience, woefully uneducated when it comes to the requirements of building regulation and electrical certification.
QUOTE]

The 'regulations' are quite different in some aspects to England and Wales, have a look at # 63 & 76
Click to expand...
 
Damn web site, I said this Sparkychick;

The 'regulations' are quite different in some aspects to England and Wales, have a look at # 63 & 76.
 
I really don't know how this situation has come about but if some testing was done prior to the consumer unit being changed it shouldn't. If I walked in I would want to do the following
1 inspect existing intake
2 Ze have I got a good starting point of the installation my MFT is the older Megger MFT uses 2 leads for high Ze test this test alone would of come to the conclusion of reversed polarity at this point.
3 check bonding for compliance and continuity
4 prove what is on each of the existing circuits
5 undertake dead testing this once again would prove polarity earth continuity etc.
At this stage I have Ze and R1 +R2 and can work out design Zs for new protective devices I have ring continuity etc I am sure that you get the idea.
Now I am not claiming maybe like some that I'm whiter than white and know everything and some will now say I have in theory gone about it all the wrong way but I feel that applying a bit of common sense before starting this would of been addressed and rectified the problem now for the electrician (and I would not want to apply fault to him as he is not here to post a reply) is he has on the face of it put himself liable .As for the debate regarding should the electrical supply be left on is this the protective device in now in the neutral with the mcb switched off the circuit is still live also it can't have a good affect upon anything with electronics inside.
 
I promised an update to the saga. The electrician came this morning and within 10 minutes had established that the meter tails were installed incorrectly (ie reversed). He kicked himself for not having checked for polarity reversal prior to the CU installation and he maintains that he reinserted the tails as they were oriented in the previous fuse box. But he refused to insist that was the case accepting that he may have inadvertently made the mistake and was much humbled and chastened that either he caused it and/or he left it that way (whoever caused it originally). As soon as the tails were swapped my wee socket tester responded well with three lights flashing! The electrician used a number of different testing devices.
For the next few hours there was a lot of testing and form filling.
The form was completed on his tablet and he emailed it to me before he left: It is a Domestic Electrical Installation Certificate (Requirements for Electrical Installations - BS7671 Wiring Regulations). A 6 page document with lots of details which I will peruse thoroughly when I have more time.
The electrician apologised profusely for his errors of testing and not paying sufficient significance to the L&N reversal.
I got to look in the open CU while the electrician was here this morning and I took a photo of his work. A snap of the meter tails and some surface wiring is shown too.
As far as I am concerned the problem has been resolved for now though I am still planning to have a complete EICR done in the near future.
 
opencu.jpg


tails.jpg
 
thanks for the update. however, being picky, i can see 3 possible issues with how he's left it now. i stress that these are in no way dangerous at present, but could cause problems in the future.

1. the tails entering the CU appear to be hard up against the metalwork. where's the grommet?

2. the tails from the meter should be restrained with cleats to prevent them being tugged and putting a strain on the terminals.

3. why are there 3 or 4 cables in the no.3 breaker when there are spare ways?
 
Hard to see but I hope he used grommet strip where cables enter the back of the consumer unit.
Vol we are picky buggers at times but at least the electrician admitted he should have checked and no harm came of it.
 
Thanks telectrix. Let me answer to the best of my ability:
1. it's a bit difficult to see but if you look really hard (at the bottom right of the CU in the photo) you can see that the CU is mounted on a wooden panel. The tails actually go up behind the wooden panel which is raised from the wall on two battens.
2. Fair point, Will be attended to next time an electrician comes in (won't be long!)
3. This was left by agreement but is part of a future plan. The house wiring is a bit all over the place (thus the pleasant mild surprise when the RCDs worked first time of asking) and it would have been a much bigger and different job to balance the various circuits across the board. So this job was just to swap to the CU as was: tThe CBs were designated on the panel for the obvious zones they controlled. In addition, there is so much surface cabling with cables going all over the place to surface mounted outlets that I want to investigate exactly what CB controls which outlet. Scaredy cat I may be but I wasn't prepared to do that while it was a traditional fuse box with old potentially disintegrating fuse wire holders!
Not an ideal situation but the balancing of the circuits will take place when the new kitchen circuit is put in soon and another electric shower too.
 
Vol said:
I promised an update to the saga. The electrician came this morning and within 10 minutes had established that the meter tails were installed incorrectly (ie reversed). He kicked himself for not having checked for polarity reversal prior to the CU installation and he maintains that he reinserted the tails as they were oriented in the previous fuse box. But he refused to insist that was the case accepting that he may have inadvertently made the mistake and was much humbled and chastened that either he caused it and/or he left it that way (whoever caused it originally). As soon as the tails were swapped my wee socket tester responded well with three lights flashing! The electrician used a number of different testing devices.
For the next few hours there was a lot of testing and form filling.
The form was completed on his tablet and he emailed it to me before he left: It is a Domestic Electrical Installation Certificate (Requirements for Electrical Installations - BS7671 Wiring Regulations). A 6 page document with lots of details which I will peruse thoroughly when I have more time.
The electrician apologised profusely for his errors of testing and not paying sufficient significance to the L&N reversal.
I got to look in the open CU while the electrician was here this morning and I took a photo of his work. A snap of the meter tails and some surface wiring is shown too.
As far as I am concerned the problem has been resolved for now though I am still planning to have a complete EICR done in the near future.
Click to expand...
Can you give us a quick precis of the information your electrician entered on the EIC?Please
 
Here is another image showing the cables going up the rear of the wooden panel. I have no idea what the entry point of the tails to the CU actually is at the rear. However, the internal work done on the CU looks neat and "professional" so I'm going to assume that everything is OK with respect to the tails entering the CU.
rps20170508_150634_623.jpg
 
The only one i can see on the report just above the testing schedule info I sent, Measured Ze: 0.65. The other parameters you describe are not included on the report that i can see, other than on the testing schedule info I already uploaded. What I mean is there isn't any box into which any of these test values could be written, unless I'm just overlooking them. Are you sure that this particular form requires a test result rather than just confirmation that a test was or was not done? I can't see any boxes for these values, it's not that the electrician has left them empty.
 
Other values I can see:
Nominal frequency: 50Hz
External earth fault loop impedence Ze (2/3): 0.57
Prospective fault current (2/3): 0.5

the report also states that he used for testing equipment, a Kewtech KT64 (might be 84, hard to read)
 
When changing a consumer unit I would expect to test and record R1+R2 values for radial circuits, r1, rn, r2 and R1+R2 values for ring final circuits. Insulation resistance for each circuit. Zs for each circuit and RCD trip times for each RCD/RCBO on the board.

These prove continuity of the protective conductors on the circuit (R1+R2) and go a long way to proving the correct polarity of the circuits, end to end continuity of ring final circuits (r1, rn and r2), give an indication of the condition of the cables and demonstrate there is nothing on the fixed install that might trip the RCDs (IR), demonstrate that the circuit can meet the requirements to achieve the maximum disconnection times required by BS7671 (Zs) and that the RCDs will operate in a manner that should save your life (RCD trip times).

Without these tests you can't say the installation is safe and in my opinion, he should not really have signed it off.
 
Vol said:
Other values I can see:
Nominal frequency: 50Hz
External earth fault loop impedence Ze (2/3): 0.57
Prospective fault current (2/3): 0.5

the report also states that he used for testing equipment, a Kewtech KT64 (might be 84, hard to read)
Click to expand...
file:///C:/Users/Pete/Downloads/BS_7671_2008_AMD3-2015_Model_Forms(3).pdf
Nothing akin to this see download
 
I would be very surprised if the RCD trip times were .2ms and .3ms as those results suggest. Especially as it appears the result show 5 circuits, but there appear to be 6 in the board spread equally across 2 RCDs.
 
Vol, do you have a snap shot of the 'Circuit Details' and the 'Test Instrument Used'?

PS good that the dangerous fault has now been rectified. Its a shame your electrician didn't do all the form filling in and testing in the first place.
 
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Just been looking at a forum on the ------.org website. Some bright spark says that the average pass rate is 60%? Not sure about the significance of that except I guess that not all electricians are right all of the time and then they forget! This has been a case in point! My electrician needs a refresher course!
Thanks for all the help I did get. Many of the early answers were right on the button and were as I thought: not overly dangerous except in specific conditions and probably the meter tails had been swapped over. I actually emailed over the weekend to British General, the manufacturer of the CU, and this morning they answered saying much the same.
I've tried to show willing in response to the help I did get by showing as much info from today's resolution as I could. I'm done now. Obviously not perfect, but then again, who is?
As for those that jumped on this bandwagon started by Midwest "Are you thinking what I'm thinking and probably what everyone else is thinking, or am I being just too cynical suspicious", please adopt a more constructive, more friendly approach next time and please change your motto from Guilty Until Proven Innocent! :) Cheers!
 
There we go, you naughty boys & girls. Consider yourselves duly chastised, You must try harder to be Friendly & Helpful in future.
Forget the fact that over the course of a year, you freely give up your time to help probably hundreds of people and do so in a Friendly, Courteous & often Humorous manner.

Oh yes: Stop being so Cynical and Suspicious :p:D
 
Vol, I am glade after all this time this has been resolved for you however I must say that on the electrician discovering the reverse polarity after installation of the consumer unit being that the meter tails are so easily seen this would and could of been spotted immediately and would taken a couple of minutes to rectify its the fact that you was left for over a week like this. I hope we have all learnt something from this.
 
I simply don't believe that ANY BODY practising as a Spark can "miss" reversed polarity on the testing - I always test the old board then the new board and my Metrel won't conduct the Ze test with reverse polarity.

Dare I ask how much you paid and whether you received an invoice?
 
Some circuits are run surface and should be rectified in future ?
Whats the world record for speed of reaction of a 30 m/amp Rcd ?
200 M/ohm across the board seems like a very common reading for insulation resistance of well used installations these days ;)
The consumer unit is a 11 way,the test schedule lists 5 ways,the 2 Rcds seem to have 3 circuits each ,decisions,decisions,try as I will,I just can't make sense of what has been produced
 
Is that right a measured ze of 0.65 ohms?
The zs results are less than the ze?
Wonder what the earthing system was.
Supposed he must have measured zs rather than the calculation as the zs readings would be higher with the calculation.
 
Des 56 said:
Some circuits are run surface and should be rectified in future ?
Whats the world record for speed of reaction of a 30 m/amp Rcd ?
200 M/ohm across the board seems like a very common reading for insulation resistance of well used installations these days ;)
The consumer unit is a 11 way,the test schedule lists 5 ways,the 2 Rcds seem to have 3 circuits each ,decisions,decisions,try as I will,I just can't make sense of what has been produced
Click to expand...
I've never got rcd test results that low haha
0.02 and 0.03 of a second
Edit
Or is it 0.2 and 0.3 of a second I can't make it out?
 
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