Changes Within BS 7671:2018: Part 1 Scope, Object and Fundamental Principles
Changes Within BS 7671:2018: Part 1 Scope, Object and Fundamental Principles
Changes Within BS 7671:2018: Part 1 Scope, Object and Fundamental Principles
Installations designed after 31st December 2018 will have to comply with BS 7671:2018.
The Regulations apply to the design, erection and verification of electrical installations, also additions
and alterations to existing installations. Existing installations that have been installed in accordance
with earlier editions of the Regulations may not comply with this edition in every respect. This does
not necessarily mean that they are unsafe for continued use or require upgrading.
A summary of the main changes is given below. (This is not an exhaustive list).
Part 2 Definitions
Definitions have been expanded and modified.
Metallic pipes entering the building having an insulating section at their point of entry need not
be connected to the protective equipotential bonding (Regulation 411.3.1.2).
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 411.3.2.2).
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.
The regulations concerning IT systems (411.6) have been reorganized. Regulations 411.6.3.1
and 411.6.3.2 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.
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Chapter 42 Protection against thermal effects
A new Regulation 421.1.7 has been introduced recommending the installation of arc fault
detection devices (AFDDs) to mitigate the risk of fire in AC final circuits of a fixed installation
due to the effects of arc fault currents.
Regulation 422.2.1 has been redrafted. Reference to conditions BD2, BD3 and BD4 has been
deleted. A note has been added stating that cables need to satisfy the requirements of the
CPR in respect of their reaction to fire and making reference to Appendix 2, item 17.
Requirements have also been included for cables that are supplying safety circuits.
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)
(a) results in serious injury to, or loss of, human life, or
(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.
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Section 534 has been completely revised and the most significant technical change refers to the
selection requirements for the voltage protection level.
In addition, a new Regulation 710.421.1.201 states requirements regarding the installation of AFDDs.
Section 730 Onshore units of electrical shore connections for inland navigation vessels
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.
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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.
Appendices
The following main changes have been made within the appendices
Appendix 1 British Standards to which reference is made in the Regulations includes minor changes,
and additions.
The recommendations within the scope of this appendix apply for new electrical installations and
modification of existing electrical installations. Much of this appendix will not apply to domestic and
similar installations.
It is intended that this appendix is read in conjunction with BS IEC 60364-8-1, when published in 2018
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