On March 1st BSI launched a summary of the changes that can be expected in the new 18th Edition BS 7671:2018 Requirements for Electrical Installations.The new standard will be issued on 2nd July, 2018.Electrical contractors and electricians will have a six month transition period to get up to speed with the changes. From January 1 2019, it will then be a requirement that all electrical installations designed after this date comply with BS 7671:2018, 18th Edition (2018).
Part 1 Scope, object and fundamental principles
Regulation 133.1.3 (Selection of equipment) has been modified and now requires a statement on the Electrical Installation Certificate.
Metallic pipes entering the building having an insulating section at their point of entry need not be connected to the protective equipotential bonding (Regulation 4126.96.36.199).
The maximum disconnection times stated in Table 41.1 now apply for final circuits up to 63 A with one or more socket-outlets and 32 A for final circuits supplying only fixed connected current-using equipment (Regulation 4188.8.131.52).
Regulation 411.3.3 has been revised and now applies to socket-outlets with a rated current not exceeding 32A. There is an exception to omit RCD protection where, other than a dwelling, a documented risk assessment determines that RCD protection is not necessary.
A new Regulation 411.3.4 requires that, 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.
Regulation 411.4.3 has been modified to include that no switching or isolating device shall be inserted in a PEN conductor.
Regulations 411.4.4 and 411.4.5 have been redrafted.
The regulations concerning IT systems (411.6) have been reorganized. Regulations 4184.108.40.206 and 4220.127.116.11 have been deleted and 411.6.4 redrafted and a new Regulation 411.6.5 inserted.
A new Regulation group (419) has been inserted where automatic disconnection according to Regulation 411.3.2 is not feasible, such as electronic equipment with limited short-circuit current.
Chapter 42 Protection against thermal effects
Chapter 44 Protection against voltage disturbances and electromagnetic disturbances
Section 443, 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 overvoltages is needed are no longer included in BS 7671. Instead, protection against transient overvoltages has to be provided where the consequence caused by overvoltage (see Regulation 443.4)
(b) results in interruption of public services/or damage to and cultural heritage, or
(c) results in interruption of commercial or industrial activity, or
(d) affects a large number of co-located individuals.
For all other cases, a risk assessment has to 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 46 Devices for isolation and switching
A new Chapter 46 has been introduced. This deals with non-automatic local and remote isolation and switching measures for the prevention or removal of dangers associated with electrical installations or electrically powered equipment.
Also, switching for the control of circuits or equipment. Where electrically powered equipment is within the scope of BS EN 60204, only the requirements of that standard apply.
This chapter has been completely revised and deals with general requirements for protection, isolation, switching, control and monitoring and with the requirements for selection and erection of the devices provided to fulfil such functions.
Section 534 Devices for protection against overvoltage
This section focuses mainly on the requirements for the selection and erection of SPDs for protection against transient overvoltages where required by Section 443, the BS EN 62305 series, or as otherwise stated.
This section contains a number of small changes, including requirements for external influences (Regulation 704.512.2), and a modification to Regulation 704.410.3.6 concerning the protective measure of electrical separation.
This section contains a number of changes including requirements for socket-outlets, RCD protection, and operational conditions and external influences.
This section contains only minor changes including modifications to Regulation 715.524.201.
This section contains a number of changes including requirements electrical separation, RCDs, proximity to non-electrical services and protective bonding conductors.
This is an entirely new section and applies to onshore installations dedicated to the supply of inland navigation vessels for commercial and administrative purposes, berthed in ports and berths.
Most, if not all, of the measures used to reduce the risks in marinas apply equally to electrical shore connections for inland navigation vessels. One of the major differences between supplies to vessels in a typical marina and electrical shore connections for inland navigation vessels is the size of the supply needed.
The following main changes have been made within the appendices:
British Standards to which reference is made in the Regulations includes minor changes, and additions.
Time/current characteristics of overcurrent protective devices and RCDs. The previous contents of Appendix 14 concerning earth fault loop impedance have been moved into Appendix 3.
Model forms for certification and reporting
This appendix includes minor changes to the certificates, changes to the inspections (for new installation work only) for domestic and similar premises with up to 100 A supply, and examples of items requiring inspection for an electrical installation condition report.
This appendix includes changes regarding rating factors for current-carrying capacity.
The contents of Appendix 14 concerning earth fault loop impedance have been moved into Appendix 3. Appendix 14 now contains information on determination of prospective fault current.
This is a new appendix that provides recommendations for the design and erection of electrical installations including installations having local production and storage of energy for optimizing the overall efficient use of electricity.
It is intended that this appendix is read in conjunction with BS IEC 60364-8-1, when published in 2018.