Using BS3871 MCB to protect ne submain

Is it ok to connect a new submain to an existing spare 3 phase BS3871 MCB in a light industrial installation. The alternative is to change the entire main DB.

Submain will be clipped direct to wall and steel roof beam. It will feed a new 3 phase DB, probably equipped with two 3 phase 16A MCB's.

My understanding is that BS 60898 replaced BS3871 and the standards are similar, I am sure there are some differences, but do they make a significant impact on safety? In my mind providing they disconnect in the required time everything should be acceptable? Main risks will be after the sub board using modern devices.

Thanks

Parents
  • 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.

Reply
  • 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.

Children
  • 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.

    Agreed - it's the simple principle, though, of "when should and when should I not ignore changes in an existing installation".

    After all, extending a lighting circuit to add a smoke detector/alarm (that did not at the time have surge protection to latest standard) is, at its core, a very similar discussion to extending a circuit to add a socket-outlet (which doesn't have ADS according to BS 7671 for protection against electric shock).

    Fundamentally, both potentially affect life-saving issues, both are non-conformances, and a decision must be taken by the designer/installer