So what? The document is merely guidance.
Best practice to add socket and light to understairs cupboard
- Thread starter Geetar500
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The document is the governments advice on how to comply with part P of the buliding regulations. They state that one should comply with a specific edition of BS7671.
They could have said that people should comply with the latest edition of BS7671 but they did not.
They could have said that people should comply with the latest edition of BS7671 but they did not.
As far as I know, they fixed it and re-included reference to BS7288 in 18th+A2
I don't particualy like RCD accessories though... they show up poles to earth insulation tests unless you trip them before you turn the power off, and folk have a tendancy to put them in the daftest places where you cant find them untill you have spent a while investigating the low reading
I think thats to do with the way law makers like to work. If they pinned it to the latest version of a standard, then effectivly what the law requires can change (when the standard does) without the normal law making process, and that cannot be allowed, I think the term ambulatory was used when it was explained (I think it might have even been on here.... or if not on IEE/IET)
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I struggle a little with this aspect, more truthfully I struggle a lot.
What makes RCD sockets and RCD FCUs useless?
It's more complicated than that, as you say basically a law cannot be made which will automatically change at some future time. It can be written such that an amendment must be ratified when the referred document changes, however if that amendment is not done for some reason( of which there are many senarios) then the law basically becomes moot. Once the law has fallen into redundancy (for the want of a more suitable term) it is then a complete mare to repeal a law in such a situation (as it 's no longer lawful) and attempting to reinstate it requires a complete process and that will fall at the first hurdle as such a law exists in the statute books and it's not permitted to have 2 similar laws.
Next problem: A law is dated, a law referring to a latest standard etc can only refer to the latest standard at the time the law was made. If such a law were written and sommething got to court the barristers would have a field day.
Just to say - the Approved Documents are not law nor indeed is BS7671.
ADP does quote (in shaded green) the very few actual laws of the Building Regulations; namely the very short and vague Part P and the notification requirements - but Part P says nothing about with which standards the work should comply, merely that safety must be ensured - therefore stating a particular edition of BS7671 shall be used could be viewed as irrelevant and indeed a mistake - just like the private rental system safety inspections.
Never assume those in charge know what they are doing.
ADP does quote (in shaded green) the very few actual laws of the Building Regulations; namely the very short and vague Part P and the notification requirements - but Part P says nothing about with which standards the work should comply, merely that safety must be ensured - therefore stating a particular edition of BS7671 shall be used could be viewed as irrelevant and indeed a mistake - just like the private rental system safety inspections.
Never assume those in charge know what they are doing.
As I understand it there are a couple of issues, though they look like they may be in the process of being fixed.
As I understand it back in the 16th edition BS7671 didn't specify specific standards for those RCDs, only trip currents and trip times, so as long as a RCD socket/FCU met the trip time/current requirements it was acceptable. Starting with the 17th edition they now specify a specific list of standards for RCDs and BS7288, the standard for RCD sockets/FCUs was not on the list. There was an article where a spokesperson from the IET claimed this was a mistake, but afaik they have not updated it in later revisions to BS7671. Possibly because of the second issue.
The second issue is that the 17th edition, while greatly expanding RCD requirements also changed the terminology used for RCD protection, under the 16th edition the required RCD protection was for "supplementary protection", under the 17th edition it is for "additional protection". Unfortunately BS 7288:2016 specifically said that RCDs to the standard were only suitable for "supplementary protection" and specifically said they were not suitable for "fault protection" or "addtional protection".
It appears that amendment 1 to BS7288:2016 has fixed the issue, and now says that they are still not suitable for "fault protection" but they *are* suitable for "additional protection".
Exactly.
Supplementary means additional.
It's like people who think supplementary bonding is a special category of bonding rather than just additional bonding.
That is nonsense.
Even if you agree with that, if the upstream MCB offers fault protection then the additional protection by the RCD in the socket is satisfactory.
Terms in standards can often have somewhat different meanings from the ordinary English understanding of those combinations of words. "exposed conductive part", "live conductor", "low voltage" the list goes on.
I've now got access to a copy of BS7288:2016 and this is what it says (retyped because it wouldn't let me copy and paste)
"SRCDs are only intended to provide supplementary protection downstream of the SRCD, SRCDs are intended for use in circuits where the fault protection and additional protection are already assured upstream of the RCD"
I looked through the definitions in BS7288 and did not find any definition of "supplementary protection", "additional protection" or "faulr protection" so I'm going to assume those are meant in the same sense as in BS7671. I'm fairly sure BS7671 only uses the term "additional protection" in reference to RCDs.
I suspect the intent was to remind people that SRCDs would not provide protection for the wiring upstream of the RCD (and hence if not RCD protected would have to be installed in a manner suitable for non-RCD protected wiring), but that it got garbled along the way.
Amendment 1 appears to have added an extra peice of text saying that SRCDs can provide additional protection, but they don't seem to have removed the original text.
"SRCDs are only intended to provide additional protection downstream of the RCD, SRCDs are intended for use in circuits where the fault protection (indirect contact protection) is already assured upstream of the RCD"
Well, as said the wording is confusing and amateurish.
Re: removing the original text; there are many such instances where related regulations are not amended to correspond with new ones.
When it says RCDs may only be used as additional protection, it just means that all the usual forms of protection must be in place as well.
As with supplementary bonding the additional protection is not a special category; it just means extra.
Presumably the likes of SPDs and AFDDs are now also additional protection but obviously they cannot be used instead of the usual protection either.
Re: removing the original text; there are many such instances where related regulations are not amended to correspond with new ones.
When it says RCDs may only be used as additional protection, it just means that all the usual forms of protection must be in place as well.
As with supplementary bonding the additional protection is not a special category; it just means extra.
Presumably the likes of SPDs and AFDDs are now also additional protection but obviously they cannot be used instead of the usual protection either.
We installed RCD sockets in a plant room to the consultants spec, each outdoor RCD DSSO on C16 or B20 MCB, 4mm² singles in 150x150mm trunking and 25mm conduit.
As such the wiring didn't require RCD protection, in fact virtually nothing else in the trunking had RCD protection, but at final inspection (by the main contractor - Laing) it was decreed that as a socket circuit RCD protection had to be fitted in the DB, so had RCBO and RCD.
As such the wiring didn't require RCD protection, in fact virtually nothing else in the trunking had RCD protection, but at final inspection (by the main contractor - Laing) it was decreed that as a socket circuit RCD protection had to be fitted in the DB, so had RCBO and RCD.
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