BS7671 - AMD2 DPC

Recently the DPC for Amendment 2 of BS 7671, 18th Edition was released for public comment.

After a bumpy start accessing the proposed changes the BSI site made some changes and it is now more easy to access for review.

It is important that everyone takes this opportunity to read through these proposed changes and considers making any comments that they feel necessary for review.

To access the DPC for AMD 2 head to the BSI Standards development portal. You will find that the standard has been broken into four separate parts due to the documents size:

  1. Chapters 1 to 45
  2. Chapters 46 to 55
  3. Chapters 56 to Section 740
  4. Section 753 to Appendix 17

It's important that you review each document and make any necessary comments to each of these four parts.

So, let's take a look at some of the suggested changes.

Part 2 Definitions

Definitions have been expanded and modified.

Chapter 41 Protection against electric shock

Section 411 contains a number of significant changes. Some of the main changes are mentioned below. Regulation 411.3.1.2 has been redrafted.

The regulation now requires that in each building (rather than installation) both incoming and outgoing metallic parts which are liable to introduce a dangerous potential difference be connected to the main earthing terminal. Where non-metallic pipes, e.g. plastic, enter the building and are then connected to metallic pipes within the building, the metallic pipes within the building do not require protective bonding.

Reference to insulating sections has been removed. In Regulation 411.3.3, the exception allowing RCD protection to be omitted where a documented risk assessment determines that RCD protection is not necessary has been removed.

Chapter 42 Protection against thermal effects

Regulation 421.1.7 has been redrafted. It is now a requirement (rather than a recommendation) to protect final circuits supplying socket-outlets and fixed current using equipment with a rated current not exceeding 32 A using arc fault detection devices (AFDD).

The regulation recommends AFDDs for all other final circuits but allows AFDDs to be omitted where unexpected disconnection of the circuit could cause danger and gives examples.

The use of AFDDs does not obviate the need to apply one or more measures provided in other clauses in this standard.

Regulation 422.1 (precautions where particular risks of fire exist) now introduces requirements for the fire safety design of the building(s) to be documented.

Regulation 422.2 now introduces separate requirements for escape routes and a new concept of “protected escape routes”. Reference to conditions BD2, BD3, and BD4 have been deleted.

Chapter 44 Protection against voltage disturbances and electromagnetic disturbances

Regulation 443.4 for determining if protection against transient overvoltages is needed has been redrafted. Regulation 443.4.1 now requires protection against transient overvoltages to be provided where the consequence caused by the overvoltage could result in:

  1. serious injury to, or loss of, humanlife
  2. significant financial or data loss.

Except for single dwelling units, for all other cases where the consequences of an overvoltage of atmospheric origin are considered to be intolerable, a risk assessment has to be performed in order to determine if protection against transient overvoltages is required. Regulation 443.4.2 requires protection against overvoltages to be considered in the case of equipment likely to produce switching overvoltages or disturbances and gives conditions.

Section 514 Identification and notices

Section 514 contains a number of significant changes (including illustrations of notices have been removed and examples are provided in Appendix 11).

Table 52 has been modified slightly to take into account changes of colour identification for DC and abbreviations have been added.

Regulation, 514.9.2 has been introduced concerning diagrams and charts.

Regulation 514.12 (Notices: periodic inspection and testing) now contains an exception for domestic (household) premises in certain situations.

Regulation 514.12.2, concerning the RCD notice, has been modified and now contains an exception for domestic (household) premises in certain situations.

Regulation 514.14.1, concerning non-standard colours, has been modified and now contains an exception for domestic (household) premises in certain situations.

Chapter 54 Earthing arrangements and protective conductors

Section 542 Earthing arrangements

Regulation 542.1.2.202 has been introduced which requires foundation earth electrodes for new premises where the protective measure is automatic disconnection of supply. Guidance on foundation earth electrodes is given in a new informative Annex A542.

Section 543 High protective conductor currents

Modifications have been made to regulation group 543.7 concerning earthing requirements for the installation of equipment having high protective conductor currents.

Chapter 64 Initial verification

The regulation group 643 has been redrafted. The requirements for testing insulation resistance where equipment is likely to influence the verification test or be damaged has been clarified and reference is made to a 250 V DC test.

Section 703 Rooms and cabins containing sauna heaters

Regulation, 703.414.3 concerning SELV and PELV, has been introduced.

Section 704 Construction and demolition site installations

Regulation 704.44, Protection against voltage disturbances and electromagnetic disturbances has been introduced Changes have been made to requirements for wiring systems and the requirements for devices for isolation have been redrafted.

Section 706 Conducting locations with restricted movement

Requirements for protection against electric shock have been redrafted. Regulation 706.415, requirements for additional protection, has been introduced.

Section 710 Medical locations

Changes include requirements concerning socket-outlet circuits in the medical IT systems and minor changes to requirement concerning luminaires and lighting installations. Also, requirements concerning diagrams and documentation have been changed. Requirements for IT systems have also been redrafted.

Section 711 Exhibitions, shows and stands

Regulation 711.410.3.101 concerning RCD protection, SELV/PELV supplies and electrical separation, has been introduced. Regulation 711.411.4 has been expanded to take account of PME. Requirements for isolation and switching have been redrafted. In addition, the regulations covering luminaires and lighting installations have been redrafted.

Section 712 Solar photovoltaic (PV) power supply systems

The technical content of this Section has been extensively revised and expanded. Requirements of this Section now apply to:

  • PV installations not connected to a system for distribution of electricity to the public,
  • PV installations in parallel with a system for distribution of electricity to the public,
  • PV installations as an alternative to a system for distribution of electricity to the public,
  • appropriate combinations of the above.

Section 714 Outdoor lighting installations

This Section includes changes concerning additional protection.

Section 717 Mobile or transportable units

Regulation 717.411.4 has been expanded to take account of PME. Also, the Annex of Section 717 has been expanded to provide guidance on voltage monitoring devices.

Section 722 Electric vehicle charging installations

This Section incorporates Amendment 1; 2020 of BS 7671:2018 together with other changes, such as, taking account of prosumer’s electrical installations.

Section 753 Heating cables and embedded heating systems

Changes include the addition of two regulations (relocated from Chapter 53) covering the installation of heating cables.

Chapter 82 Prosumer’s low-voltage electrical installations

This is an entirely new Chapter. Historically, utility companies have managed the public transmission and distribution network from the point of view of having central production adapted to demand variation. The objective of this Chapter is to provide requirements, such that, low-voltage electrical installations are compatible with the current and future ways to deliver safely the electrical energy to current-using equipment either from the public network or from other local sources.

Chapter 82 provides additional requirements, measures and recommendations for design, erection and verification of all types of low-voltage electrical installations. This includes local production and/or storage of energy in order to ensure compatibility with existing and future ways to deliver electrical energy to current using equipment or to the public network by means of local sources. Such electrical installations are designated as Prosumer’s Electrical Installations (PEIs).


The following main changes have been made within the Appendices:
Appendix 6 Model forms for certification and reporting Minor changes have been made to the model forms and guidance for recipients. These include the addition of a field referring to the AFDD test button on the Minor Electrical Installation Works Certificate. One key change to the Electrical Installation Certificate is the addition of a field referring to schedule of inspections covering items 1 to 10 with descriptions.

A new checklist of items requiring inspection during initial verification has been added to Appendix 6 and this is referenced in the Electrical Installation Certificate, as mentioned above. The previous list of items requiring inspection during initial verification has been deleted. Also, the schedule of inspections (for new work) for domestic and similar premises up to 100A supply has been deleted, since these two schedules are now both covered by the new checklist.

Appendix 7 Harmonized cable core colours This appendix includes minor changes to align with the latest standards concerning identification of conductors.

Appendix 11 Warning and user instruction labels This is a new appendix that provides guidance for the types of safety signs, warning signs and instructions required to be applied to electrical installations.

Appendix 13 Escape routes and fire protection The previous content of Appendix 13 concerning methods for measuring the insulation resistance/impedance of floors and walls to Earth has been removed and replaced by guidance on escape routes and fire protection. The new content of Appendix 13 provides detailed guidance on protected escape routes in order to afford a safe passage through the building to an exit.

Appendix 17 Energy efficiency This appendix includes changes to the scope to cover dwellings and reference to the Building Regulations, changes to user decisions, also new design recommendations, new information on determination of meshes, new information on user requirements, new guidance covering impacts on the design of an installation, and new guidance on periodic assessment.

Learn more

To help understand and discuss these proposal I hosted a couple of webinars with the e5 group to go through these changes with a chat room full of electricians.