TT eicr code?

[spark 68]

A question for Spin, or anyone else for that matter.

When I was getting trained for T&I it was suggested (not written) not to go back more than one or two editions as other problems arise, I will list just a few problems that would not be acceptable now in chronological order backwards obviously missing the 16th as that was the immediate prior edition.

15th ed VOELCBs discontinued in one of the late 15th amds before the 16th, no means of testing now, and deemed an obsolete method now.
14th ed no supp bonding required in bathrooms and no RCD requirement (unless TT)
13th ed, prior to 1966 no CPC requirement at lighting circuits and also the water pipe was permitted to be used as a means of earthing.
(I know there is a "workaround" for the no CPC at lighting problem)

Clearly even if these were permitted at the time they would result in C2s now and therefore a fail now, no ?

The guidance given by the ESC seems to bear out my lecturer's assertion that we should not go back more than an edition or two before some updating becomes necessary would you agree with that assertion or not ?

 

[Richard Burns]

An s-type won't be less than 200ms as a non-adjustable type-s is built with this figure as a time delay. A type-s can never be used to provide fault protection on a circuit where 0.2s is the maximum permissible disconnection time.

Just for information the specification for a time delayed RCD to BSEN61008 has maximum trip time of 150ms if there is a significant fault current (=>5Idn) so it would meet the disconnection times for a 0.2s (200ms) circuit on a "fault of negligible impedance".

 

[Engineer54]

Makes me wonder how any of us, (including all those millions of farm animals) ever managed to survive for all these years, what with all those higher disconnection times no RCD's etc, etc, etc!!
Strange how those previous disconnection times reigned as ''safe'' for literally 10's of years, as did Zs values without any of this 80% crap!!

So does all this imply that previous editions of BS7671 and beyond, weren't fit for purpose, and that installations that fully met with those previous editions, have somehow now become in some eye's ...bloody dangerous??? I doubt if you'll ever get the ITE to agree, or go along with those comments!! I wonder what they will say about the regulations you are all working to now in the future?? Do any of you think, that the installations you are installing now, are or could be called actually called dangerous in the future??

Oh and as far as i'm aware, a water pipe can still be used to this day as an installations sole means of earthing in the UK !! Provided it's derived from a private source/well and not from a public utility source!

Training, Experience, Commonsense (none of which seem to be held in any regard these days) should be able to distinguish what is relevant and what isn't, with regards to coding a particular non-compliance with the current 17th edition.

 

[D Skelton]

Just for information the specification for a time delayed RCD to BSEN61008 has maximum trip time of 150ms if there is a significant fault current (=>5Idn) so it would meet the disconnection times for a 0.2s (200ms) circuit on a "fault of negligible impedance".

Yes I know this, but what about on a fault of significant impedance?

 

[Richard Burns]

Not covered by BS7671

 

[D Skelton]

So does all this imply that previous editions of BS7671 and beyond, weren't fit for purpose, and that installations that fully met with those previous editions, have somehow now become in some eye's ...bloody dangerous???

Bloody dangerous is a bit strong isn't it?! lol

I doubt if you'll ever get the ITE to agree, or go along with those comments!! I wonder what they will say about the regulations you are all working to now in the future?? Do any of you think, that the installations you are installing now, are or could be called actually called dangerous in the future??

Potentially, and if this were the case I wouldn't be bitter about it, I'm happy to move with the times my learned friend

Notice I didn't use the words 'old' or 'stubborn' in my reply to you!

 

[D Skelton]

Not covered by BS7671

Conventionally, but it has always been my understanding that they are not excluded from BS7671, fault current is fault current at the end of the day. Happy to be corrected and told otherwise however. One thing though, how would you ascertain that the RCD would indeed trip within 150ms when we don't carry out 5x tests on anything higher than 30mA RCDs?

 

[stevethesparks]

If anyone is going to base whether an installation is safe according to the regs at the time of the installation, they would need to know the date of installation, how often are we blessed with this information? Once upon a time fused neutrals were considered a good idea. Its really up to the individual at the time to make an educated assessment of coding required, many amendments are for the better, some have taken a backward step IMHO. I like to base my decisions on worse case scenarios, can't go far wrong then.

 

[D Skelton]

If anyone is going to base whether an installation is safe according to the regs at the time of the installation, they would need to know the date of installation, how often are we blessed with this information? Once upon a time fused neutrals were considered a good idea. Its really up to the individual at the time to make an educated assessment of coding required, many amendments are for the better, some have taken a backward step IMHO. I like to base my decisions on worse case scenarios, can't go far wrong then.

Ahh, the voice of reason!

 

[Richard Burns]

Conventionally, but it has always been my understanding that they are not excluded from BS7671, fault current is fault current at the end of the day. Happy to be corrected and told otherwise however. One thing though, how would you ascertain that the RCD would indeed trip within 150ms when we don't carry out 5x tests on anything higher than 30mA RCDs?

If you have a fault where the resistance is between 7660Ω and 2300Ω then the RCD would (probably) not trip in <0.2 s however it is not required to according to BS7671. This would be a similar situation to MCBs that will not trip in the required time if the fault current is low; similarly how do you know and MCB will trip in the time stated, you do not know, you are relying on the manufacturers making them to standard. It is not (in standard situations) safe to test this compliance.

 

[D Skelton]

If you have a fault where the resistance is between 7660Ω and 2300Ω then the RCD would (probably) not trip in <0.2 s however it is not required to according to BS7671. This would be a similar situation to MCBs that will not trip in the required time if the fault current is low; similarly how do you know and MCB will trip in the time stated, you do not know, you are relying on the manufacturers making them to standard. It is not (in standard situations) safe to test this compliance.

You are quite right, however we still record the disconnection time on a 100mA at 1x and 1x only. This is the disconnection time at its rated current, which is higher than 200ms, therefore it will not comply.

 

[Richard Burns]

You are quite right, however we still record the disconnection time on a 100mA at 1x and 1x only. This is the disconnection time at its rated current, which is higher than 200ms, therefore it will not comply.

There is a difference between the requirements to meet disconnection times and the requirements to test if the RCD functions.
The disconnection times would be met so long as the Zs reading complied.
The 100mA time delayed RCD tripping in >130ms<500ms at Idn shows that it is working.

 

[D Skelton]

Yes, and in a fault, depending on its conditions, the RCD may or may not trip in less that 200ms, that is my only issue.

 

[Richard Burns]

OK I think I am at a loss to explain here.
The disconnection time of 0.2s for a fault of negligible impedance, which is required by the regulations, would be met.
The RCD would not necessarily disconnect in 0.2s under all circumstances but this is not required at all by the regulations.

 

[Engineer54]

If anyone is going to base whether an installation is safe according to the regs at the time of the installation, they would need to know the date of installation, how often are we blessed with this information? Once upon a time fused neutrals were considered a good idea. Its really up to the individual at the time to make an educated assessment of coding required, many amendments are for the better, some have taken a backward step IMHO. I like to base my decisions on worse case scenarios, can't go far wrong then.

If you were experienced, you would/should be able date an installation to a regulations edition, with some accuracy. Unlike today, Regulations didn't change at anywhere near the regularity they do today... Unfortunately we have 17 day whizz kids and electrical trainee's undertaking/conducting EICR's that haven't got a clue what they are looking at, let alone being remotely able to make an educated assessment. Depends on what you mean by ''worst case'', ..if that means assessing a totally improbable scenario, as being possible, what is that saying?? lol!!

 

[Engineer54]

So what was actually wrong with the long standing previous 0.4 second disconnection times?? Which i might add, is still the disconnection time value for many countries around the world, as well as TN ADS systems in the UK!!

 

[stevethesparks]

No matter how experienced one is, you could never always prove that an installation was installed as per requirements at the time.
I've been in this game 42 years this coming June , and I'm still blimim learning!
I like to try and keep up to date, and have many reference books at my side, its great to know they will all be out of date again come next January. You are certainly right about regs not changing like they do today.

 

[D Skelton]

So what was actually wrong with the long standing previous 0.4 second disconnection times?? Which i might add, is still the disconnection time value for many countries around the world, as well as TN ADS systems in the UK!!

I never said anything was wrong with them, just that where an RCD is used for fault protection on a TT system the maximim permitted disconnection time is now 0.2s. Higher than this is considered unsafe by BS7671:2008

 

[Engineer54]

No matter how experienced one is, you could never always prove that an installation was installed as per requirements at the time.
I've been in this game 42 years this coming June , and I'm still blimim learning!
I like to try and keep up to date, and have many reference books at my side, its great to know they will all be out of date again come next January. You are certainly right about regs not changing like they do today.

Then you should have no problem dating an installation to a reg's edition. lol!! I didn't say you shouldn't test, ....testing is the only way you are going to be sure of any findings you make. Now come on, after 42 years in the game, do you really NEED all those installation by numbers OSG's etc??

 

[Engineer54]

I never said anything was wrong with them, just that where an RCD is used for fault protection on a TT system the maximim permitted disconnection time is now 0.2s. Higher than this is considered unsafe by BS7671:2008

Do you get ''deaded'' faster with a TT installation than a TN one then?? Or is it more about ensuring that RCD protection is included into all TT installations to prop up their 200 ohm Ra value?? lol!!:wings: Don't take this post too seriously now will you!! lol!!

 

[D Skelton]

Do you get ''deaded'' faster with a TT installation than a TN one then?? Or is it more about ensuring that RCD protection is included into all TT installations to prop up their 200 ohm Ra value?? lol!!:wings: Don't take this post too seriously now will you!! lol!!

Haha, no of course not, but when the current regulations deem something unsafe, then I will code it appropriately.

 

[stevethesparks]

Then you should have no problem dating an installation to a reg's edition. lol!! I didn't say you shouldn't test, ....testing is the only way you are going to be sure of any findings you make. Now come on, after 42 years in the game, do you really NEED all those installation by numbers OSG's etc??

I'm afraid I do.
Once upon a time, I could quote regs numbers, but i seemed to have developed a type of dyslexia to all those numbers now lol. Too many regs referring to other regs for my liking.
When I update with a 17th edition course, I thought I was boy wonder again, but its all gone to mush again since :-(
I reckon I could still kick some arse installing MICC, making trunking sets that have near enough been banned, and bashing in some conduit with some intricate bends, but having spent most of my career on that side of the industry, I am almost enjoying catching up on the other side of things, and apart from my reference books, find many posts here enlightening.

I do believe when I attended college all those years ago insulation resistance and ring continuity with a wind up megger was about the most testing that happened. It could just be my memory though.

 

[spark 68]

Part of the difficulty of dating an installation accurately (unless it is untouched and pristine), is that it is often a mish mash of different editions, for example it may have been originally installed to say the 12th then re-wired to the 15th, then at some point had the CU updated to the 16th etc..etc.

We can only really have an educated guess, unless there is prior paperwork (lol in domestic).

Where I disagree with Damien is that I would not fail a fully compliant 16th ed install, it is when you start going further back is where more and more problems arise, and the recommendations become more C2 than C3

The 0.4 disconnection time in the 16th was only for S/Os or final circuits which supply portable equipment and handheld class 1 equipment, for other fixed final circuits a disconnection time of not more than 5 seconds was permitted.

In my view the 16th edition is adequately safe, with no more than a C3 in respect to coding, going any further back and you start attracting C2s.

 

[Engineer54]

I'm afraid I do.
Once upon a time, I could quote regs numbers, but i seemed to have developed a type of dyslexia to all those numbers now lol. Too many regs referring to other regs for my liking.
When I update with a 17th edition course, I thought I was boy wonder again, but its all gone to mush again since :-(
I reckon I could still kick some arse installing MICC, making trunking sets that have near enough been banned, and bashing in some conduit with some intricate bends, but having spent most of my career on that side of the industry, I am almost enjoying catching up on the other side of things, and apart from my reference books, find many posts here enlightening.

I do believe when I attended college all those years ago insulation resistance and ring continuity with a wind up megger was about the most testing that happened. It could just be my memory though.

Much of the work i was doing during my training days (industrial manufacturing sector) and after, was testing!! Everything from ELV to MV installations, to systems control, using test equipment that went way way beyond IR and continuity tests.

Like you, i couldn't quote or spurt off Reg numbers, only really ever look at them, if i want a confirmation, or looking at another aspect of what can be done... I know what you mean about memory though!! lol!!

 

[stevethesparks]

Part of the difficulty of dating an installation accurately (unless it is untouched and pristine), is that it is often a mish mash of different editions, for example it may have been originally installed to say the 12th then re-wired to the 15th, then at some point had the CU updated to the 16th etc..etc.

That the bit I was trying to convey, but you have explained it better than I.

 

[Badged01]

These debates are good as it allows a good exchange of idea/onfo on a topic! I've often questions what the "tecnicalities" of the PIR process is so the thread has made me re-think my position so I thought I'd add my summized interpretation/view to continue the debate on PIR generally .....

Only guidance BS7671 (17th edn) gives on PIR is that it is conducted to determine :

1) If the installation is 'satisfactory' for continued use (note 'safe' not used )
2) That the requirements for disconnection times set out in BS7671(17th edn) are complied with
3) That departures from these regs BS7671 (17th edn) that may give rise to danger are identified.
4) On completion of the PIR an EICR shall be given to ..... showing any non-compliances to BS7671 (17th edn) that may give rise to danger.

And of course we have the caveat at the beginning of BS7671 (17th edn) that states previous installations may not conform with the requirements of BS7671 (17th edn) but that does not mean they are unsafe for continued use (note 'satisfactory' not used)

BS7671 (17th edn) offers an EICR model form along with guidance on codes to be use for observations raised within the EICR :
C1 -- Danger present (defined as risk of injury to persons/livestock)
C2 -- Potentially dangerous
C3 -- Improvement recommended
[Note : 'Observations' is not defined within BS7671 (17th edn) ]

In support of BS7671 (17th edn) we have documentation issued by the ESC on EICR's which is supported by all the major players in the industry (ECA, NICEIC etc ... ) and of course by the IET who 'own' BS7671 (17th edn). The key points it raises are:

1) The EICR provides an assessment against the requirements of the edition of BS7671 current at the time of the inspection, irrespective of the age of the installation.
2) It describes 'observations' as something which would contribute to a significant improvement in safety of the electrical installation and can be supported by one or more regulations in the edition of BS7671 being current at the time. Observations based solely on personal preference or 'custom and practise' should not be included.
3) The guide then advises that it is entirely a matter for the 'competent' person to decide on the classification code to use but gives specific example of where it believes a code should be applied.

My interpretation of the above means that I conduct EICR's using the model form in BS7671 and do it against the current edition of BS767 (17th edn) and any non-conformance to the 17th edn regulations I record as an observation. My view if is that if it wasnt a safety improvement on previous regs it wouldn't have been updated in the 17th edn. I then code that observation using the ESC guidance. If not covered in there then based on my 'experience' I decide if I consider it dangerous or not.

Bottom line is I believe my 'butt' is covered by following BS7671 (17th edn) and the ESC guidance should there questions/prosecution arising from my PIR. But as a 'competant' inspector there is nothing stopping anyone not following any guidance and conducting a PIR as they see fit and then reporting the results of that inspection in any form they want to ---- until something goes wrong and they are asked for justification. Or more importantly perhaps under the EAWR proving innocence rather than the prosecution having to prove guilt!

In the example contained within this thread Im in agreement with Mr Skelton -- if it doesnt meet disconnection times C2. I'm just reporting my findings to the customer against the current BS7671 and its upto him if he wants to ignore them or do something about them. I can't make him do anything if he doesn't want to.

 

[Engineer54]

That all fine, but giving a fail code to a circuit or whatever, that has proved to have been adequately suitable (fit for purpose) and in working order and hasn't been changed a jot, since installed. The only change being made being a disconnection time change. I think you would need to be able to substantiate giving that situation a fail code!! Code 3 is fine!!

I'm yet to be convinced, that a 0.2 difference in disconnection times is going to make much if any difference in a situation where RCD's are basically mandatory (TT systems) for compliance with earth fault disconnection times!!!

 

[JD6400]

Badged01, I am on the fence on this one all be it leaning slightly towards Damian and your self's view , after this post .
Good argument well put IMO !



Edit ; I say on the fence , but have always gone with a C3 until now .

 

[spark 68]

One last question for those that would C2 a compliant 16th edition install. lol

How are you going to code existing 17th installs once 17th amd3 becomes the new standard with reduced max Zs's and all that this implies ?

Edit: Badged I gave you a like for your very good post, but I don't agree with you wrt 16th, the regs are not retrospective as such, and to fail an immediately previous edition is harsh IMO, I would still C3 it, and make a note that it complied with that previous edition, ie. recommend improvement.

If it was earlier, say 15th with a VOELCB, which are now classed as an ineffective protective measure, then yes a C2 is appropriate.

 

[Badged01]

Ultimately its down to the inspector if he wants C2 or C3. For me the key question you have to answer is if it doesn't comply with the latest 17th edn regs for a new build would you accept it as being satisfactory and sign off the new build paperwork (the installation is safe to go)? If you wouldn't sign it off why not (old installations to 16th edn meet those disconnection times)? If you wouldn't sign it off for those reasons why do you consider an old installation disconnection times acceptable on an EICR?

Code C2 or C3 is a judgement call, mine is a C2 - potentially dangerous. If the old disconnection times were acceptable why did we change them? In reality you can give either as the only time you would need to justify the code would be should an 'accident' happen and my butt is covered

And yes, there will be further issues with installations now designed to specific disconnection time in the 17th edn which may not now comply with new times in the BYB!! At what point do you draw the line in the sand and say any disconnection time from the XXth edition is acceptable ......

 

[spark 68]

This is not about new builds though, where I would agree with you.
We are talking about existing, was the 16th so Dangerous that we are instructed to update to the latest and greatest ? no of course not.

Why then would you think that the immediate previous edition should fail just because the rules have since changed since it was installed ? I am only talking about the immediate previous edition here because if you go back further then other things start becoming C2s.

Fail is the operative word here, recommending improvement is the fairest for this situation.

My question still stands, how are you going to code existing 17th installs when amd3 kicks in with reduced max Zs's and what complies now suddenly doesn't ?

Edit: of course any new work or additions on existing you do has to comply to current regs, which I agree with, but we are talking EICRs here

 

[Badged01]

We are talking about existing, was the 16th so Dangerous that we are instructed to update to the latest and greatest ? no of course not.

Then why not just use the old disconnection times for new builds? What reason would you have for changing disconnection times with an update in regulations -- to make it less safe? I could understand perhaps if they had stated all new builds must meet these new xx times but old builds are permitted to meet these xx disconnection times?

Why then would you think that the immediate previous edition should fail just because the rules have since changed since it was installed?

That is a question only those who decided to give new disconnection times in the 17th edn can answer. I can only assume if they thought the old times were satisfactory/safe they would have left them at that? I just interpret and code as I see in the latest (17th edn) regs, which for me is C2. I have no arguement if you say C3 thats your interpretation.

I am only talking about the immediate previous edition here because if you go back further then other things start becoming C2s.

So who makes the technical/engineering decision as to what is acceptable or not? I dont think thats down to you or me! To play the devils advocate you could say the times in xx regs of 193X were acceptable then --- who's to say they arent now? Again a interpretation of whay you feel the 17th edn means.

My question still stands, how are you going to code existing 17th installs when amd3 kicks in with reduced max Zs's and what complies now suddenly doesn't ?

Good question and until I view the BYB and what it says I cant really answer. But yes, I think there will be issues in that what is an acceptable disconnection time on the last day of the BGB may not acceptable on the first day of the BYB! By your interpretation then, on issue of the BYB do all the 16th edn times become unacceptable as one removed from the previous disconnection times (BGB) or does that only occur at the 18th edn when presumably all the 17th edn times are still OK?

Food for thought, makes for an intersting debate!

 

[spark 68]

OK, let's add a bit of perspective here, as things are seldom black and white.

A fully complaint 16th ed install although not meeting 17th regs, how can you say it is potentially dangerous ? which is what a C2 is.
Fair enough it could maybe do with some improvements, improved safety is always a good thing hence a C3 IMO.


Earlier editions start to become a moot point, it was proven that old VOELCBS became ineffective because they relied on the Voltage of the MET rising to about circa 45-50V to operate, precisely what effective Earthing and bonding was designed to prevent, hence their discontinuation, a verified C2.

The regs have always been about practicality versus safety, which is why we have dual RCD boards which are not fully 17th compliant either.
If you look at the ESC guide it has quite a few "get out clauses" for earlier editions, such as undersized MB, no RCDs on S/O unless for outdoor use (C3), and a "workaround" for no CPCs on lighting etc..etc, the exception being for those things that are since proven to be potentially dangerous, ie. thermal cut-outs on immersions, VOELCBS, using the public water supply as a means of earthing, fused Neutrals etc...etc..

My earlier question about reduced Zs's btw, expect a similar "workaround" of some sort to be issued, because it would cost a massive amount of money if that was retrospectively applied to industrial and commercial buildings.

 

[Guest55]

during a periodic inspection , the condition of an electrical installation is put in comparison to the current regulations at the time of the inspection , not at the time it was constructed.

to suggest otherwise is ridiculous.

and how would you absolutely confirm its age anyway , without original documents or an engraved plaque on the wall ?

so does this mean that without understanding of , lets say , the 15th ed. your deemed incompetent to test & inspect ?

how far back do you want to go ?
wheres the timeline drawn between relevent / obsolete ?

does this mean anyone under the age of 45 is probably too young to be deemed suitable / competent to carry out periodics then ..............?

bollox.

 

[spark 68]

during a periodic inspection , the condition of an electrical installation is put in comparison to the current regulations at the time.

to suggest otherwise is ridiculous.

so without understanding of , lets say , the 15th ed. your deemed incompetent to test & inspect ?

which means anyone under the age of 45 is unsuitable to carry out periodics then ..............

bollox.

I didn't say that at all, I know we compare to current regs, but you should also be aware of previous requirements too, the issue is coding.

To say that a fully compliant 16th edition is potentially dangerous is also ridiculous, there may be some issues that could be improved, but to fail an install that was installed as late as 2008 ?

A tester is supposed to have above average knowledge and experience of wiring regulations not just the current edition.

If you only needed knowledge of the current edition then the (2394) IV course would be all that is required.

 

[JD6400]

I think this one is going to end up on a perpetual loop !

Spark 68 , I think that was a well levelled response . #83

Although we should all be singing from the same hymn sheet !? I also believe that as Badged01 points out , some aspects of a PIR ( or what ever they deem it to called now ) can be down to personal judgement on the more sketchy points , with in reason ! After all it will be your signature at the end of the day , if the :****: does happen to hit the fan one day !
Take a low IR reading of say around 6 , although it passes , in most instances I would not wish to leave such a latent defect , but I was taught it is a ( now ) C3 !

 

[Guest55]

If you only needed knowledge of the current edition then the (2394) IV course would be all that is required.

how do you work that out ??

the 2395 doesnt teach old versions of regs , it just has a course content with a different bias.

 

[spark 68]

how do you work that out ??

the 2395 doesnt teach old versions of regs , it just has a course content with a different bias.

GN3 states that the tester/inspector should have a sound technical knowledge and experience relevant to the nature of the installation being inspected and tested, and of BS671 and other technical standards.

Read into that what you will, how can you be competent to T&I older installs if you only know about new installs ?

The 2391 and later courses were designed for experienced sparks, until the training providers jumped on the band wagon, why do you think the failure rate is so high ?


Edit: so if you only know the 17th then just fail everything else, is that what you are saying ?

 

[Deleted member 26818]

There seems to be a distinct lack of common sense it his thread.
Do people really believe that the IET would produce a set of Regulations, that would place themselves in a position where they could face litigation for allowing unsafe installations?

At present, the Regulations allow an installation to be constructed to to an edition of the Regulations for an indefinite time, after that edition has been super superseded.
For example many aspects of the Olympic Village in Stratford were designed while the 16th edition was in force, and were constructed to the 16th edition, right up to 2012, some 4 years after the 17th edition was introduced.
It is conceivable that the modifications to the residences currently underway, are also being constructed to the 16th, although I have no personal knowledge of this.
To my knowledge, none of the Olympic site is TT, and as such the disconnection time of 0.2 secs is not an issue.

However we come back to the ridiculous situation, where according to some an installation can be safe at one minute to Midnight, yet become unsafe at one minute past. Simply because a certain date has been reached.

An Inspector should be using his or her sound judgment and experience to make informed decisions about whether an installation is fit for continued use.
What has been suggested is not sound judgment, and to my mind suggests lack of experience.

 

[spark 68]

Exactly spin,

At least badged gave his technical reasons as to why he would C2, even though I don't agree with him.

Part of the problem I feel is down to lack of experience with the earlier standards, It is not the newer sparks's fault either, but to say if it does not comply to the latest regs is an automatic fail just beggars belief.

I have enjoyed contributing to this thread immensely, it has certainly opened my eyes to prevailing attitudes though.

I have said enough on this topic now, and I will bow out after this post, while it may make me possibly unpopular for saying this, sadly the attitude of newer (and some older) sparks that everything must comply to the latest regs or is potentially unsafe, just shows the lack of training and experience now endemic in our industry as a whole.

I can understand this state of affairs with those sparks who predominately just install new stuff, but really they should not be carrying out EICRs on older properties if the attitude is to just update everything or fail automatically.

I agree that in an ideal world that updating everything would without a doubt improve the safety somewhat, but unfortunately reality rears it's ugly head.

A fascinating thread all the same, and very revealing.

 

[Des 56]

Thank goodness for 2 voices of reason in the last 2 posts in this thread

My last post as well on the subject
The arguments have been presented and in my opinion, it is not and never has been in any doubt from the onset

A compliant 16th edition installation should not be considered potentially dangerous just because the date on the calender has changed

 

[D Skelton]

OK, let's add a bit of perspective here, as things are seldom black and white.

A fully complaint 16th ed install although not meeting 17th regs, how can you say it is potentially dangerous ? which is what a C2 is.

Because the regs say so! It really is that simple

BS7617:2011 621.2 states; "Periodic inspection comprising a detailed examination of the installation shall be carried out . . . to show that the requirements for disconnection times . . . are complied with to provide for the safety of persons and livestock".

As I said in an earlier post, that says to me that if disconnection times are not met then the safety of persons and livestock is not provided for, thus making the installation unsafe. A C2, according to the regulations, is the only code that can be given.

 

[spark 68]

D I really have said enough on here already, lol

last post from me (unless I get dragged in again) lol

sigh, 621.1 where required, periodic inspection and testing of every electrical installation shall be carried in accordance with 621.2 to 5 (which includes the bit you have posted above), in order to determine so far as reasonably practicable, whether the installation is in a satisfactory condition for continued service.

it goes on to say, wherever possible the documentation arising from the initial certification and any previous periodic I&T shall be taken into account (yeah right lol).

Where no previous documentation is available, investigation of the electrical installation shall be carried out prior to carrying out the PIR.

Now what investigation do you think they mean prior to carrying out the PIR ? after all the PIR is an investigation in itself, could it be to determine what edition it is maybe ?

Why would you expect an earlier editions disconnection times to comply with a later editions, when you know for a fact that the later editions were shortened ?

In the absence of prior paperwork for a known earlier edition, then I would look to the earlier standards to determine what was acceptable then, this is the beginning of my investigation prior to the PIR.

And on the off chance that an original EIC existed (lol) , and your current test results happened to reasonably match it, then what ? after all we are only looking for significant detioriation.

 

[Engineer54]

Because the regs say so! It really is that simple

BS7617:2011 621.2 states; "Periodic inspection comprising a detailed examination of the installation shall be carried out . . . to show that the requirements for disconnection times . . . are complied with to provide for the safety of persons and livestock".

As I said in an earlier post, that says to me that if disconnection times are not met then the safety of persons and livestock is not provided for, thus making the installation unsafe. A C2, according to the regulations, is the only code that can be given.

As i pointed out before, what detailed examination is going to distingquish between a trip time of 0.4 and 0.2 sec, when an RCD device is the main source of earth fault protection?? Same goes for a L-N fault protected by a MCB.

 

[D Skelton]

As i pointed out before, what detailed examination is going to distingquish between a trip time of 0.4 and 0.2 sec, when an RCD device is the main source of earth fault protection?? Same goes for a L-N fault protected by a MCB.

I'd examine the supply characteristics, in detail lol. If TT then 0.2s maximum disconnection time for general circuits where an RCD is used for fault protection applies. If that maximum permitted disconnection time cannot be met, I'd C2 it.

I think we've all said our piece, and well I might add on both sides of the argument.

Talk about topics that split the forum! lol

 

[Badged01]

Do people really believe that the IET would produce a set of Regulations, that would place themselves in a position where they could face litigation for allowing unsafe installations?

The above is very true, but my slant is probably different to what the poster meant!

The IET will update the regs to cover their 'butts' and currently they will stand behind the disconnection times in the BGB as being 'safe' as far as is reasonable practicable to understand at present. Then presumably the 'new, disconnection times in the BYB when issued!!. (Otherwise why change the times?) They legally can't make any location be upgraded to the latest edition of the regs (which are recommendations not enforceable law), so cant be prosecuted if 'old' installations don't meet the current 'safe' requirements. Infact they don't know if the old installations don't actually meet the latest disconnection times as they have no visibility! (I'm not in the mind of the IET so don't know their thinking behind changes to the times but my own industrial work experience of upgrading processes, procedures and instructions/guidance has always been to make things better/safer not the other way around!!)

I guess their get out clause would be that "we discharge our duties by stating what is 'recommended' as being safe in the current regs and rely upon 'competent' inspectors conducting EICR's of old installations (when required by owners, not legally enforceable) to intepret our regs to ensure the disconnection time is safe and advise the owner accordingly". i.e. we've passed the buck down to the inspector to check if its safe when inspecting to our latest regs!

But ask yourself the question, should little Johnny get electrocuted and you have signed the EICR saying the 16th edn disconnection times are C3 and the installation is satisfactory for continued use, even when there is a more stringent disconnection time to be applied in the current regulations which your are conducting your EICR to and you know about - you're the competent inspector?. When the defence call the 'expert' witness from the IET, what disconnection time do you think he is going to stand behind as the recommended safe time? I dont think he will be saying any time from the 15th/16th edn or the IET could then be liable to litigation themselves in approving/recommending the 'unsafe' disconnection time which killed little Johnny! And if you know anything about big organisations, one thing they are very good at is covering their own butts and happily sacrificing the worker (inspector) if it suites their ends.

If nothing else cover your own butt and go "C2" -- the customer doesn't have to upgrade if he doesn't want to, you can't make him (same as the IET) but atleast you have advised him about the potential risk! If they want to argue further about the disconnection time being safe or not they can take that up with the IET, whose guidance on the subject you have followed

I'ver waffled on far too much and enough has been said on the post for the layman to choose his own position. So like the previous posts, this is my last post before agreeing to disagree with everyones interpretation of C3 and disgracefully bowing out with old age. The thread could go on and on and round and round otherwise ......

 

[Engineer54]

I'd examine the supply characteristics, in detail lol. If TT then 0.2s maximum disconnection time for general circuits where an RCD is used for fault protection applies. If that maximum permitted disconnection time cannot be met, I'd C2 it.

I think we've all said our piece, and well I might add on both sides of the argument.

Talk about topics that split the forum! lol

Tut, tut, tut, ...what i'm saying is, if the circuit or circuits are protected with an RCD device, it wouldn't matter a jot if it was 0.2 or 0.4 sec disconnection times!! You can examine the supply characteristics etc all you like, so long as the RCD device passes the standard tests, it's a good'un!!

Now if you want a topic that we DO disagree on. Check out this thread!! lol!!

http://www.electriciansforums.co.uk...rum/88682-eal-test-inspection.html#post919002

 

[D Skelton]

Tut, tut, tut, ...what i'm saying is, if the circuit or circuits are protected with an RCD device, it wouldn't matter a jot if it was 0.2 or 0.4 sec disconnection times!! You can examine the supply characteristics etc all you like, so long as the RCD device passes the standard tests, it's a good'un!!

Now if you want a topic that we DO disagree on. Check out this thread!! lol!!

http://www.electriciansforums.co.uk...rum/88682-eal-test-inspection.html#post919002

It would matter if the RCD in question wouldn't disconnect in the required time

 

[telectrix]

never seen a RCD that didn't meet the 0.2 secs @ x1. always get < 50mSec.( unless, of course it's faulty).

 

[spark 68]

Badged mate you have a 0.2 disconnection time as your reason for a C2, fair enough, but you are still wrong.

if you have a look in the current regs (BGB) at reg 411.3.2.2 under the table in that reg it points you to 411.3.1.2 and tells you that if protective equipotential bonding as per 411.3.1.2 is present (incoming water, gas etc.), then TN values (0.4s) for your disconnection time may be used for a TT system.

This is in the current regs, not the 16th, lol

In a fully compliant 16th ed install, 411.3.1.2 in the 17th, would be met anyway, and don't forget S/Os (and showers) would be covered by a 30mA device in the 16th too which would disconnect in 40ms @ 5Idn

Edit: OK the above applies to where an OCPD is used for disconnection, but further reading relating to RCDs as a means of fault protection in 411.5.3 states the disconnection time shall be either 411.3.2.2 or 411.3.2.4 and RA X Idn <=50

it then says the requirements of this regulation are met if the ELI of the circuits protected by RCD meet the values in table 41.5 in the BGB
, which they would do even in the 16th