JPEL committee member Frank Bertie unravels some of the finer details behind the upcoming changes in Amendment 2 for BS 7671:2018 (2022).
Although the Draft for Public Comment (DPC) period ended in December of last year, the proposed changes to BS 7671:2018 that were included in the DPC have implications for the electrical industry.
Although the publication date of March 2022 does seem some time away still, we’ll need to start considering the changes to ensure it doesn’t cause delays or problems for installation practices.
As with all Amendments to BS 7671, it’s only when all of the comments that were received during the DPC period have been reviewed and considered that the final version of BS 7671 Amendment 2 is issued. As such, some of the proposed changes we’re discussing may or may not come into force.
What will change with Amendment 2?
Although we’re discussing a proposed document, the information contained in it comes mostly from harmonised documents and the content will be implemented in some form within the United Kingdom.
Regulation 411.3.3 additional requirements for socket-outlets
The removal of the exemption to (i) for RCD protection for socket-outlets not exceeding 32 A, will have major implications for any electrical contractor carrying out this work in commercial or industrial sectors.
RCD protection ≤ 30 mA will now be required for:
● 13 A BS 1363 socket-outlets,
● 16 A, 32 A BS EN 60309 single and three-phase socket-outlets.
This will apply in all areas regardless, even if considered low risk.
So, does this mean every circuit must have an RCD/RCBO installed within the distribution board?
There are several different options depending on the installation type:
● For BS 1363 general socket-outlets, an RCD/RCBO at the distribution board would be the most suitable solution, although this is dependent on the items of equipment which may have a total sum of leakage current that would cause unwanted tripping of the RCD.
For office layouts the use of a socket outlet strip can have an RCD incorporated in each outlet, as shown in Fig 1.
● For BS EN 60309 socket-outlets, when used to supply cabinets in a data centre, this may result in the installation of rotary isolators, fused connection units, or via fixed terminal junction boxes.
As with other amendments to BS 7671, this requirement is not retrospective and would not necessarily require upgrading or coding on an EICR.
Arc Fault Detection Devices
With the change to Regulation 421.1.7 it will now be mandatory to install Arc Fault Detection Devices (AFDDs), as shown in Fig 2, for final circuits supplying socket-outlets and fixed current using equipment not exceeding 32 A. This may have a major impact on the design of installations and the configuration of consumer units and distribution boards in all types of installations.
The recommendation for installation in all other final circuits would have to be taken into consideration when installing the mandatory AFDDs in the consumer unit or distribution board. There are several examples where the AFDDs may be omitted if the disconnection could cause danger.
Selection of RCD
There has been a minor change regarding unwanted tripping of RCDs where Regulation 531.3.2 has a new indent:
(ii) the use of RCBOs for individual final circuits in domestic installations.
RCBO consumer units have been available for several years and the only restriction on installing them has been the increased cost of multiple RCBOs.
A major change in the installation of RCDs is included in 531.3.3 where Type AC RCDs shall only be used to serve fixed equipment, where it is known that the load contains no DC components, and this can lead to issues where the RCD protection can be compromised.
Type AC RCDs will start to be phased out as many of the manufacturers have been changing to type A RCDs in their product ranges, as shown in Fig 3.
Foundation earthing
The most controversial introduction within Amendment 2 is foundation earthing as this involves part of the building process which is out of the electrical contractor’s control.
Regulation 542.1.2.202 states that for new premises with foundations a form of earth electrode is required from one of the following options:
i. a concrete embedded foundation earth electrode in accordance with Annex A542 or
ii. a soil embedded ring electrode in accordance with Annex A542 or
iii. an equivalent earth electrode such as that afforded by metalwork of a steel-framed building embedded in concrete foundations in contact with soil.
This may be seen as a case of bolting the stable door after the horse has run off, but in reality it will hopefully provide a solution to the situation of a break in the PEN conductor in the distributor’s network, which often results in the earthed metalwork rising in potential for a TN-C-S (PME) installation.
What would it mean to electrical installations?
The requirement only applies to new premises with foundations, therefore the majority of installations would not have to install the foundation earthing.
For new builds with foundations, the electrical contractor or a specialist contractor would have to be involved from the design stage to ensure the foundation earth electrode is correctly installed in the concrete foundations, as shown in Fig 4.
Conclusion
When Amendment 2 of BS 7671:2018 is introduced, it will involve changes for all electrical installations. NAPIT will provide webinars and EXPO events where we can deliver further information on the changes concerning BS 7671:2018 (2022) for our membership and the electrical industry.
Get more information on NAPIT scheme registration by clicking here
