Alan B said:

Interesting debate, just wondering if there is anything I can do to make it acceptable to use the existing BS3871 device.

It has been an interesting debate.

Do we not always say that the Regs are not retrospective?

Surely modifications, which may not strictly comply with the current Regs may be made to an installation provided that the result is not less safe than the existing situation.

Chris Pearson said:

Surely modifications, which may not strictly comply with the current Regs may be made to an installation provided that the result is not less safe than the existing situation.

Well, the EIC and MEIWC require you to certify that the installation conforms to the stated version of BS 7671. So, Provided you list ALL the departures on the EIC or MEIWC (and have a good reason for them), perhaps?

Is that approach acceptable to everyone? I'm reminded of the following types of discussion:

•  Domestic smoke detection and SPD requirements in line with BS7671 A2 2022 
• https://www.fia.uk.com/news/fia-s-proactive-efforts-lead-to-crucial-amendment-correction.html

This forum has become very flawed and isn’t really fit for purpose.

That post linked to about SPDs and smoke alarms is simply dated as “over a year ago “ without giving an exact date, and as we all know dates are very important when discussing BS7671.

The requirements were different in April and May last year 2023, as the corrigendum was published in May 2023 and it’s now the 26th April 2024.

electrical.theiet.org/.../

The discussion has also been locked, preventing anyone from commenting that the answer I gave then “over a year ago” would be different now and the context will change next week.

Sparkingchip said:

The discussion has also been locked, preventing anyone from commenting that the answer I gave then “over a year ago” would be different now and the context will change next week.

The point being, not what BS 7671 requires NOW, but that:

Chris Pearson said:

Do we not always say that the Regs are not retrospective?

Surely modifications, which may not strictly comply with the current Regs may be made to an installation provided that the result is not less safe than the existing situation.

So, it's OK to ignore current requirements for existing circuits with devices that provide ADS for protection against electric shock, but yet in terms of whether an existing circuit needs an SPD "you MUST follow new requirements" just because the current version of BS 7671 [at the time] says so ???"

I don't follow the logic.

But then again, safety engineering isn't always logic - perceived risk is always a huge factor.

Well, the EIC and MEIWC require you to certify that the installation conforms to the stated version of BS 7671.

Well, not the entire installation, just what's been installed within the scope of the certificate - i.e. the new work. In the OP's case it could be said he's extending a circuit from an existing OPD - so the new work commences at the outgoing terminals of the BS 3871 and so the MCB itself isn't included in what's being certified. So as long as it's "adequate for the altered circumstances"...

   - Andy.

I will just drop into the conversation that in September 2023 I stood and had a face to face conversation with Graham  and other IET Engineers on the IET stand at the Coventry Elex Show about surge protection, smoke alarms and requirements for smoke alarms in both privately rented homes and housing association homes.

The legislation that says landlords have to install smoke alarms only covers privately rented homes, not housing association homes.

For several years I subcontracted to a housing association contractor and that HA doesn't fit smoke alarms in the homes they rent out, it is the tenants responsibility to buy, maintain and replace them, so many of those HA homes still do not have them.

I went to Elex last year with a specific intention of visiting the IET to discuss these matters, to ensure I fully understood the correct requirements of BS7671 and how they had changed over the preceding years with Amendment 2 and the corrigendum being issued.

Requirements are taken out of the Wiring Regulations, as well as being added in, affecting how electrical installations are specified and installed. Every day is a school day, there’s always something to learn from everyone you come into contact with.

That is why I still frequently read the discussions on this forum, in amongst other sources of information and it would actually be really helpful if the discussions on this forum had the exact date on them when things were said and people could actually add a note saying that due to changes in the requirements what was a correct answer in April last year changed in May last year, so is no longer correct.

Electrical Safety First Best Practice Guide Two says BS3871 MCBs are unlikely to be suitable for isolation without explaining why 

www.electricalsafetyfirst.org.uk/.../best-practice-guide-2-issue-3.pdf

Then the ESF BPG2 shows an example of a locked off MCB, which looks remarkably like a plug in BS3871 MCB for retrofitting into a fuse board made for BS3036 rewirable fuses and/or cartridge fuses, but may be a BS60898.

www.electricalsafetyfirst.org.uk/.../best-practice-guide-2-issue-3.pdf

AJJewsbury said:

the BS 3871 and so the MCB itself isn't included in what's being certified.

The selection of the circuit-breaker to provide ADS for the addition to the circuit is included in the certificate, surely?

Sparkingchip said:

Electrical Safety First Best Practice Guide Two says BS3871 MCBs are unlikely to be suitable for isolation without explaining why 

I have explained this above - including not being marked.

However, arguably the same consideration should be made for older isolators, which also pre-dated the agreed marking, and also don't meet current standards for isolation.

My concern here is that It seems we are injudiciously applying "rules and exceptions" in some cases and ignoring others ... which can't be right?