IET announces new amendment to BS 7671 (IET Wiring Regulations)

The garage/ workshop electrical installation then needs upgrading, it can be done, but will the work make it any safer than it was in the first place?


 Andy Betteridge

Exactly.

Regards, UKPN

And apart from having to walk to the house to reset the RCD if it trips he is left holding an angle grinder in pitch darkness in a workshop where the floor is littered with trip hazards, because the lights went out as well.


Andy B.

You can picture the scenario. Jack (retired) enjoys spending his day in his workshop. He used to have an RCD double socket in his workshop and FCUs. If they tripped it was easy to reset. Then a character comes into his life and writes an EICR. Got to fail the workshop Jack, because my latest copy of Napit/Stroma/NICEIC/ECA "Codebreaker Amendment XXX says so. Jack is handy with DIY so he fits an RCD into his fuseboard in the house.


Jacks workshop is 300 yards from the house.


Regards, UKPN.

"So they cannot be installed and on an EICR they would be a non compliance so would require recording and coding"

So let me get this right, I have to remove this wonderful safety device which protects me when I am using my Flymo because its dangerous. (because the wiring regs say so)


Regards, UKPN.

That’s the first mention of some new 30 mA RCDs needing to be tested at 250 mA if they fail the the X5 test, it does appear that there has been some fudging of the Wiring Regulations to accommodate this change accepted practice.


Andy B

" SRCDS are only intended to supplementary protection downstream of the SRCD. SRCDs are intended for use in circuits where the fault protection and additional protection are already assured upstream upstream of the SRCD".


So these devices can no longer be used for additional protection.

Surely such an interpretation defies common sense? Why on earth would a standard for 30mA RCD sockets intend to demand upstream 30mA RCD protection - it just isn't logical. Isn't it far more likely that the intention was simply to re-enforce the point that the device doesn't provide upstream protection (as would be commonly be needed these days - e.g. for T&E concealed in a wall) and that something got lost in translation from during the committeeitization of the prose?

 

So BS7671, crucially in the "selection and erection" section, removed BS7288 as "accepted devices"

I don't think that BS 7288 has been "removed" as such - before the 18th there wasn't a list of acceptable devices (some devices were mentioned elsewhere and had useful data provided for them, but as far as I can tell there was no implication that other devices couldn't be equally acceptable) - just some very specific performance requirements (e.g. rated ≤30mA and opening within 40ms at 5xI_Δn). Come the 18th the performance requirements disappeared (perhaps because some devices now need 250mA rather than 150mA to open within 40ms) and we just had a list of acceptable devices instead, from which BS 7288 was absent - whether by design or error we still don't know (although I still suspect it was in error).


   - Andy.

For over twenty years I have had it drummed into me that the Wiring Regulations are not prescriptive, it is not an instruction book that tells you how to do electrical installation work.


So for over twenty years my understanding has been the Wiring Regulations tells you what you should achieve, what is required, but not how to do it.


So for RCDs it told you what level of protection is required, but did not tell you which RCD to use.


Somewhere along the way a decision was made to specifically state in the 17th edition that RCDs to three standards will meet the requirements of BS7671, industry guidance was then published to say that this list was not prescriptive and exclusive, the other types of RCD that have a British Standard and gave the level of protection required to achieve the requirements of the Wiring Regulations are still considered fit for purpose and can be used.


But then a decision was made to rewrite the British Standard 7288, now that adds a whole new issue to consider, in that the new RCDs may not be as well made as the current version, in that there is not a requirement for three millimetres of separation between the contacts when they disconnect; and may not meet an additional requirement for them to provide isolation, though they meet two British Standards and meet the requirements as a socket or fused connection unit which the Wiring Regulations states meets the requirements for isolation, but by being isolated manually rather than automatically. Is there a requirement that isolation is automatic or that is it disconnection that is required to provide the automatic disconnection of the supply, ADS, whilst the isolation is manual?


Hopefully there will be a quick resolution to these issues, with the transition to new BS8277 devices supposedly being in progress and the implementation date of the new BS8277:2016 in a few weeks time in November 2019, hopefully the resolution will come sooner rather than later.


 Andy Betteridge