Steve Redpath of PTT gives an overview of the proposed changes.
So, it’s true what you’ve heard, the 18th edition of BS7671 is coming and planned for release in July 2018.
Just as you thought you had got the hang of the 17th edition ‘they’ go and issue an 18th edition.
‘It’s to make us buy a new ‘regs’ book and make more money for the IET!’ I hear you say. Well that is one way of looking at it, but inevitably technology moves on and therefore standards must evolve as technology and buildings evolve.
In this blog, we will look at some of the planned changes. I say planned, as nothing is certain until the regs are formally released on 1st July 2018. Prior to that you/the industry can comment on the proposed changes and influence the final version.
The Draft for Public Comment (DPC) for BS 7671:2018 is now available. The DPC is your chance to see the proposed content ahead of publication and put forward your views to JPEL/64, the technical committee responsible for BS7671. Visit the BSI webpage for the DPC, sign up with your email address and access the document.
So, what are the proposed changes? We look at some of the key ‘proposals’ …
Proposed Changes in the 18th Edition
The structure of the main parts of the regs remain the same i.e. Parts 1 to 7 remain with the exception that a new Part 8 is being added.
Part 1 Scope, object and fundamental principles Regulation 133.1.3 (Selection of equipment) has been modified such that it will require a statement on the Electrical Installation Certificate.
Part 2 Definitions, these have been expanded and modified.
Chapter 41 Protection against electric shock
This contains many significant changes. Some of the main ones are mentioned below.
- The maximum disconnection times stated in Table 41.1 now apply for final circuits up to 63 A (it used to be 32A) with one or more socket-outlets and 32 A for final circuits supplying only fixed connected current-using equipment
- Metallic pipes entering the building having an insulating section at their entrance need not be connected to the protective equipotential bonding.
- Regulation 411.3.3 has been revised and now applies to socket-outlets with a rated current not exceeding 32 A (it used to be 20A).
- The exception to omit RCD protection for a specific labelled socket outlet or where, other than a dwelling, a documented risk assessment determines that RCD protection is not necessary has been deleted. The Regulation now requires RCD protection for all socket outlets.
- A new Regulation 411.3.4 requires within domestic (household) premises additional protection by an RCD with a rated residual operating current not exceeding 30 mA shall be provided for AC final circuits supplying luminaires.
Chapter 42 Protection against thermal effects
A new Regulation 421.7 has been introduced for the installation of arc fault detection devices (AFDDs) to mitigate the risk of fire in final circuits of a fixed installation because of arc fault currents.
Chapter 44 Protection against voltage disturbances and electromagnetic disturbances Section 443
This section which deals with protection against overvoltages of atmospheric origin or due to switching, has been redrafted. The AQ criteria (conditions of external influence for lightning) for determining if protection against transient overvoltage is needed, is no longer to be included in BS 7671. Instead, protection against transient overvoltage must be provided where the consequence caused by overvoltage affects human life, public services and cultural heritage, and commercial or industrial activity.
For all other cases, a risk assessment must be performed in order to determine if protection against transient overvoltage is required. There is an exception not to provide protection for single dwelling units in certain situations.
Chapter 52 Selection and erection of wiring systems Regulation 521.11. 201
521.11. 201 gives requirements for the methods of support of wiring systems in escape routes. This has been replaced by a new Regulation 521.10.202. The new Regulation 521.10.202 requires cables to be adequately supported against their premature collapse in the event of a fire. This applies throughout the installation. Not just in escape routes.
Chapter 54 Earthing arrangements and protective conductors Regulation 542.1.201 has been modified and now requires an additional earth electrode, supplementing any earthing facility provided by the distributor to prevent the appearance of a dangerous touch voltage in the event of the loss of the main connection to Earth.
Part 6 Inspection and testing
Part 6 has been completely restructured including the numbering to align with the CENELEC standard. Chapter 61, 62, and 63 have been deleted and the content of these chapters have been moved to Chapter 64 and Chapter 65 as appropriate. The forms remain mainly the same.
Part 7 Special Locations and Installations
Minor changes to most sections.
Section 722 Electric vehicle charging installations. This Section contains a significant change to Regulation 722.411.4.1 concerning the use of a PME supply. The exception concerning reasonably practicable has been deleted.
Section 730 Onshore units of electrical shore connections for inland navigation vessels. This is a completely new Section. This Section applies to onshore installations dedicated to the supply of inland navigation vessels for commercial and administrative purpose, berthed in ports and berths.
Part 8 Energy efficiency This is a completely new Part which considers how electrical installations can provide the required level of service and safety at the same time as reducing energy consumption. Part 8 will enable a client to specify the level of energy efficiency measures applied to an electrical installation. Installations can be awarded points for energy efficiency performance levels. This new Part covers several energy efficient areas, such as lighting, metering, cable losses, transformer losses, power-factor correction, and harmonics.
The timeline for the 18th edition:
- Draft for Public comment available until 23rd Aug 2017
- 18th Edition Issued 1st July 2018
- 18th Edition comes into force 1st Jan 2019
At the time of writing there has been no announcement from City and Guilds or the industry regarding an update to the wiring regulations qualification 2382. It is likely, if the 16th to 17th revision was anything to go by, that an update qualification will be available that will consist of a shortened multi-choice exam covering the main changes to the regs. PTT will keep you updated as we learn more.
