Amendment 2: Draft For Public Comment
This article gives a brief summary of the important changes affecting electrical designers and installers. It is important to note however that any or all of this information is subject to change depending on the comments received on the draft.
18th Edition Wiring Regulations
Amendment 2 to the 18th edition wiring regulations BS 7671 is due for publication in 2022. At the time of writing this article it is in the ‘Draft for public comment’ phase. This literally means what it says; anyone interested can read the draft copy and make comments. In order to do this you will need to log onto the BSI website. This is open and available until 11th December 2020. After this time the panel responsible for the content of the document (known as JPEL/64) go through all the comments made and make adjustments if required to the final document. The final document will become BS 7671:2018 Amendment 2 on 28th March 2022.
This article gives a brief summary of the important changes affecting electrical designers and installers. It is important to note however that any or all of this information is subject to change depending on the comments received on the draft. Not every alteration, addition or deletion is covered and should you wish to see the whole document this is available as stated on the BSI website.
The first change is to do with the implementation date. Conventionally there has been a 6 month transition period whereby installations designed after a certain date are to comply with the new edition. This was to allow for large projects with an extended design and installation phase. There has always been some ambiguity with this however especially with repeat installations like housing developments. The new wording says ‘Electrical installations, the erection of which is commenced after 28th March 2023, are to comply with BS 7671:2018 incorporating Amendment 2:2022’ This should therefore remove this ambiguity. Amendment 2 is still not retrospective like previous editions so there is no need to upgrade any existing installation. Additions however to an existing installation will be required to comply with amendment 2 requirements after 28th March 2023. Also, Electrical Installation Condition Reports will have to be carried out to amendment 2 requirements after 28th March 2023.
Additional protection by RCD, not exceeding 30mA is required for socket outlets and for mobile equipment up to 32A used outdoors. An exception was permitted for a socket outlet in an installation other than a dwelling if a documented risk assessment could determine that the RCD was not necessary. This exception has been deleted so every socket outlet up to 32A regardless of where it is or what it will be used for will require additional protection by RCD.
This is to do with Arc Fault Detection Devices (AFDDs). The 18th edition gave a recommendation for their use in certain installations. The new regulation says; ‘Arc fault detection devices (AFDD) conforming to BS EN 62606 shall be provided for single-phase AC final circuits supplying socket-outlets and fixed current-using equipment with a rated current not exceeding 32A’ And
‘AFDDs are recommended for all other final circuits’. There are some suggested circuits where they may be omitted as unexpected disconnection could cause danger. One such instance is ‘lighting circuits in dwellings’.
This section concerns Overvoltage protection via the use of Surge Protection Devices (SPDs). Presently there are 4 instances where surge protection devices shall be used and a risk assessment to determine whether SPDs shall be used for all other installations. Single dwelling units are not included and is up to the owner whether they wish to have SPDs installed based on a cost justification of installing them against the cost of the equipment they are there to protect. Amendment 2 has just 2 instances where SPDs shall be installed, where an overvoltage could result in:
(i) serious injury to, or loss of, human life;
(ii) significant financial or data loss
Other cases will require the risk assessment calculation to be performed. This calculation is the same formula i.e CRL = fenv / (Lp x Ng). If the result of this formula produces a CRL ≥ 1000 then Protection against transient overvoltages of atmospheric origin is not required.Essentially the same rules apply to single dwelling units, there is however a note of warning (Note 5) saying that most equipment is of overvoltage category level I or II which is potentially at risk from transient overvoltages.
This regulation requires notices such as the RCD testing and Periodic Inspection information to be affixed to a distribution board. For consumer units in domestic installations this has for a while been an issue as the Building Regulations require the consumer unit to be accessible. This has resulted in the consumer unit being installed in places such as hallways and in plain sight. For this reason manufacturers have taken great care in ensuring their consumer unit is aesthetically pleasing as possible and even offering flush boards. Then to comply with BS 7671 several stickers are usually placed on the front face. These are not wanted by the homeowner so are often removed. Amendment 2 recognises this and says the stickers need not now be applied to domestic premises as long as the Guidance for Recipients as part of the Electrical Installation Certificate is given which contains this required information.
531.3.3 Types of RCD
The 18th edition made us more aware of the existence of different types of RCDs for different protection requirements. Type A RCDs have essentially become the norm since but type AC devices still exist but have limited use. The statement in 18th edition that says ‘For general purposes, Type AC RCDs may be used’ has been altered to say ‘For general purposes, only Type A RCDs may be used’. And then it goes on to say ‘Type AC RCDs shall only be used to serve fixed equipment, where it is known that the load contains no DC components’ Some examples of this type of equipment are then given.
Chapter 54 Earthing arrangements & protective conductors
There is quite a major addition with a new regulation 5184.108.40.206. This calls for new premises constructed on foundations to have some kind of foundation earth electrode or similar. This is if ADS is used as the method of protection against electric shock which is very likely. This electrode shall have a value of resistance to earth not exceeding 20Ω and shall be required to be connected to the Main earthing Terminal via a main protective bonding conductor.
There is a brand new part (part 8) and Chapter 82. This is to do with Prosumer’s electrical installations (PEI). A prosumer is newly defined in part 2 as an ‘Entity or party which can be both a producer and a consumer of electrical energy’ This new Chapter provides requirements for PEIs to achieve safe operation, sustainability and efficient use of energy when integrated into smart grids.