TT eicr code?

[hoppy]

Thanks d Skelton, for your view point and constructive info, that's what I was after, just looking for a different view point from the more experienced guys like yourself!

thanks again!

 

[Des 56]

Regardless of whatever regulations it was designed to if the overcurrent protective devices will not disconnect the circuit under fault conditions in the required time then it's a C2. An EICR is always carried out to current regulations.

Would you not code bare live cable not out of reach but in use that was designed to the first edition of the wiring regulations?

Having just read the whole of this thread,I am going to take issue with Damien and support the veiw of Spinlondon

My own understanding is that an eicr is carried out to ascertain whether an installation is safe for continued use,it is not carried out to determine if it meets current regs, rather it is it is compared to current regs for the purpose of the report and any deviations can be coded with that in mind


In the example being discussed,a TT system with a time delay 100m/amp Rcd,it does not meet curent regs for the reasons that have been posted
If it does not meet the current regs,it is then determined if it meets the standards that were in force at the time of installation and in this case it does
Remembering why the eicr is carried out,to determine if it is safe for continued use

Now to take a view contrary to the above and code the installation as potentially dangerous C2
It means there are millions off UK households that have installations that were deemed perfectly safe at the time that are now being considered dangerous,the IET got it wrong,massive rectification is required throughout the land

That is not a situation that would be confined to this forum,it would make national headline news and the electrical institution that governs safety would be in all sorts of bother

I suspect that my own interpretation of why an eicr is carried out and what determines the compliance of the system and to what regs is the only correct conclusion

 

[D Skelton]

Having just read the whole of this thread,I am going to take issue with Damien and support the veiw of Spinlondon

My own understanding is that an eicr is carried out to ascertain whether an installation is safe for continued use,it is not carried out to determine if it meets current regs, rather it is it is compared to current regs for the purpose of the report and any deviations can be coded with that in mind

I never said it is to determine if it meets current regs, I just said that any observations that are made will be in compliance with current regs.

In the example being discussed,a TT system with a time delay 100m/amp Rcd,it does not meet curent regs for the reasons that have been posted
If it does not meet the current regs,it is then determined if it meets the standards that were in force at the time of installation and in this case it does
Remembering why the eicr is carried out,to determine if it is safe for continued use

Like I keep saying, regardless of past standards, if an OCPD will not disconnect in the required time then this is potentially dangerous, therefore the only reasonable code would be a C2.

Now to take a view contrary to the above and code the installation as potentially dangerous C2
It means there are millions off UK households that have installations that were deemed perfectly safe at the time that are now being considered dangerous,the IET got it wrong,massive rectification is required throughout the land

Are there millions of UK households on TT systems protected by a lone type-s RCD??? I've never come across one. I've come across plenty protected by a lone 100mA RCD though, in which case the requirements for fault protection (in most cases) will still be met even by todays standards.

I suspect that my own interpretation of why an eicr is carried out and what determines the compliance of the system and to what regs is the only correct conclusion

My conculsion is that there has been a gross misunderstanding of what I've actually said. I have been very clear in my explanation of the difference between a TT system protected by a 100mA type-s and a TT system protected by a normal 100mA and this appears to have been missed.

Edit: Like I said earlier, what if an electrical installation in use today complied with the 1st Edition of the wiring regulations but was unsafe for use today as it was. Would you just C3 that? I wouldn't, and I'd be perfectly comfortable giving the appropriate code by todays standards.

 

[spark 68]

Like Des, I would take issue with applying a C2 to a correctly designed 16th Edition install.

Here are the pages from the relevant 16th amd1 OSG. Sorry I don't have a later version (amd2) of the 16th OSG to compare with.

Bear in mind this type of install could have been carried out up until 2008, possibly later if it was designed prior to the 17th.

Have a read of the text pertaining to the use of RCDs in the 16th.

It would have to be a C3 from me.

 

[Des 56]

Are there millions of UK households on ?? TT systems protected by a lone type-s RCD?I've never come across one. I've come across plenty protected by a lone 100mA RCD though, in which case the requirements for fault protection (in most cases) will still be met even by todays standards.


TT systems protected by a lone type-s RCD?
I am puzzled by your quote
There are many that are split load with an additional 30m/amp Rcd covered by the whole boards 100m/amp S type

The millions statement might just be a "slight" exaggeration

nevertheless,there are indeed many many many,TT systems both now and in the past that not only employ this set up but are indeed very numerous, even until today

I am very surprised that you have never come across one,your area of the country must be very different to my own,where there is a rich mixture of all sorts and these types were as numerous as any Tnc-s or Tns



Like I keep saying, regardless of past standards, if an OCPD will not disconnect in the required time then this is potentially dangerous, therefore the only reasonable code would be a C2.

That is because you are basing your results on the current requirements and values
If they were based on what was accepted at the time of installation,then there is no problem

Obviously due regard should be taken of what time period that has elapsed since the installation date,but that is the idea of informing the person requesting the report of C3s etc
The changes will be brought to their attention for consideration,but that is much different to making a statement that their recently compliant installation is now unsatisfactory due only to changes that they would not have been aware of at the time it was installed

 

[spark 68]

One exception to the 16th and prior I would C2, is the thermal cut-out on old immersion heaters, as that was a proven defect that could cause fatalities.

It was generally acknowledged (unwritten) that on an EICR you go back one or possibly two editions before other factors start creeping in which would out of necessity would start to require improvements due to the age and purpose of the install (rental etc.), or in other words the further back you go the case becomes more compelling to require to at least update parts of the install. (more C2 than C3)

This rules out the 1st edition of the regs in this context.

The 15th edition now starting to become borderline (VOELCBs etc.), and anything prior starting to become obsolete.

 

[D Skelton]

One exception to the 16th and prior I would C2, is the thermal cut-out on old immersion heaters, as that was a proven defect that could cause fatalities.

It was generally acknowledged (unwritten) that on an EICR you go back one or possibly two editions before other factors start creeping in which would out of necessity would start to require improvements due to the age and purpose of the install (rental etc.), or in other words the further back you go the case becomes more compelling to require to at least update parts of the install. (more C2 than C3)

This rules out the 1st edition of the regs in this context.

The 15th edition now starting to become borderline (VOELCBs etc.), and anything prior starting to become obsolete.

So you consider it to be more of a personal line that dictates how far back you go before you start C2ing things. I guess I'm prepared to cross that line sooner than others when it comes to diconnection times not being met. Does that make me a frauster? Hmmm

Clearly there's nothing written down that goes into this matter, however there is plenty out there that states that periodic inspection and testing should be carried out to current regulations and older versions play no part in whether to code something or not.
I'll say it again, if something is unsafe by todays standards I'll code it appropriately. Previous standards don't come in to it in my mind.

 

[spark 68]

Are there millions of UK households on TT systems protected by a lone type-s RCD??? I've never come across one. I've come across plenty protected by a lone 100mA RCD though, in which case the requirements for fault protection (in most cases) will still be met even by todays standards.


The millons statement might just be a "slight" exageration

nevertheless,there are indeed many many many,TT systems both now and in the past that not only employ this set up but are indeed very numerous, even until today

I am very surprised that you have never come across one,your area of the country must be very different to my own,where there is a rich mixture of all sorts and these types were as numerous as any Tnc-s or Tns

I was fitting this type of install in 2006 and 2007 for the local council where I was working at the time, It was the defacto standard set-up for about 16 years, 1992 up to 2008.

 

[D Skelton]

I was fitting this type of install in 2006 and 2007 for the local council where I was working at the time, It was the defacto standard set-up for about 16 years, 1992 up to 2008.

I've never come across one. I've seen plenty of TT systems fitted with a single 100mA RCD protecting a 3036 board but never one with a type-s all on its own.

There ain't that many TT systems round here though, majority of my work is inner city so maybe that plays a part. I only get to play around with rods when I'm out in the sticks, which isn't every day.

 

[spark 68]

Hi D, it boils down to many factors, ie. is it rental where the LA might want their own improvements, or is it private.


You cannot force people to upgrade, nor can you scaremonger, it is basically a technical RA, as I said it was 'tacitly' suggested but unwritten that maybe two editions back was far enough before other factors came into play.

Edit: Have look at the drawings I posted, it was never allowed to have a single 100mA s-type protecting the whole lot, you still needed 30mA for S/Os in the 16th.

The 15th I would have to look up.

 

[D Skelton]

Hi D, it boils down to many factors, ie. is it rental where the LA might want their own improvements, or is it private.


You cannot force people to upgrade, nor can you scaremonger, it is basically a technical RA, as I said it was 'tacitly' suggested but unwritten that maybe two editions back was far enough before other factors came into play.

Is it scaremongering to say that something is unsafe by today's standards? I don't really think so. If I were to carry out an installation on a TT system today and relied on a lone s-type to protect the entire installation my work would be unsafe. Surely the same standard applies to existing installations.

 

[Des 56]

Is it scaremongering to say that something is unsafe by today's standards? I don't really think so. If I were to carry out an installation on a TT system today and relied on a lone s-type to protect the entire installation my work would be unsafe. Surely the same standard applies to existing installations.

Danien
Can you please clarify what you mean by this statement that has been made by yourself a few times
I can play with the words to get it to mean different things


Oops gotta go to watch the match

 

[spark 68]

See edit above, even now S/Os without RCDs may be a C3 (16th ed) if not used for equipment outdoors (16th ed).

As I said it is basically a technical RA, your own personal preference has nothing to do with it, the situation as a whole needs to be taken into account.

 

[D Skelton]

See edit above, even now S/Os without RCDs may be a C3 (15th ed) if not used for equipment outdoors (16th ed).

As I said it is basically a technical RA, your own personal preference has nothing to do with it, the situation as a whole needs to be taken into account.

Ok, personal preference aside. If the OP has come across a TT installation with a 30mA for sockets and a 100mA s-type protecting the rest then if I were him I'd C2 the 100mA s-type. I view this as potentially dangerous because the circuits protected by the s-type would not disconnect in the required time.

I stand by how I would code this situation.

 

[spark 68]

Hi D,

what I was saying 16th ed TT wise, is that you can use 100mA upfront where No outdoor S/O are used, or a 100mA s-type upfront feeding a 30mA half of the board (S/Os) for discrimination purposes, or a 100mA (not TD) and 30mA split, if you look at the drawings I posted it shows this clearly.
In the 16th generally only S/Os and the shower were on the 30mA side.

I also think there is a mistake in the attached text where it says "shock protection" I think it should say Fault protection.
The 100mA providing fault protection, not additional protection as defined in the 17th, hence C3.

 

[D Skelton]

Hi D,

what I was saying 16th ed TT wise, is that you can use 100mA upfront where No outdoor S/O are used, or a 100mA s-type upfront feeding a 30mA half of the board (S/Os) for discrimination purposes, or a 100mA (not TD) and 30mA split, if you look at the drawings I posted it shows this clearly.
In the 16th generally only S/Os and the shower were on the 30mA side.

I also think there is a mistake in the attached text where it says "shock protection" I think it should say Fault protection.
The 100mA providing fault protection, not additional protection as defined in the 17th, hence C3.

Yes, and the s-type would have provided fault protection as under the 16th Edition the maximum permitted disconnection time for general circuits on a TT system was 0.4s. Now it is 0.2s and an s-type wouldn't provide fault protection on a general circuit only on a distribution circuit. C2.

 

[telectrix]

but if that s-type was compliant when installed, i 'd lean towards a C3. can't see it being OK pre 17th and now potentially dangerous.

 

[spark 68]

Sorry, the 0.4 seconds in the 16th (table 41A TN disconnection times in that edition) only applied to S/Os supplying outdoor equipment, it did not apply to other fixed final circuits where a 5 seconds disconnection time was allowed.

 

[D Skelton]

but if that s-type was compliant when installed, i 'd lean towards a C3. can't see it being OK pre 17th and now potentially dangerous.

Working down an asbestos mine without a mask wasn't dangerous pre 17th.

 

[D Skelton]

Sorry, the 0.4 seconds in the 16th (table 41A TN disconnection times in that edition) only applied to S/Os supplying outdoor equipment, it did not apply to other fixed final circuits where a 5 seconds disconnection time was allowed.

Either way, under the 16th an s-type would have provided fault protection for any circuit on a TT. Now it won't. That is my reasoning.