Wiring Regulations BS7671

18th edition, blue cover, published in July 2018 and applicable to electrical installations designed from 1 January 2019.

This section covers the changes within the appendices.

Printed book available from Amazon. Note that many older editions are still available, these have different coloured covers. Make sure you are buying the correct version - BS7671:2018, blue cover.

BS7671:2018 18th Edition Appendices Changes

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There are 17 appendices. If not listed below, the appendix either has no changes of relevance, or is not used.

Appendix 1 British Standards

This appendix is a long list of other British Standards referred to throughout the rest of BS7671. There are many changes here, however all of them are due to changes in numbering, versions and similar for other standards, so the individual changes are not listed here.

Appendix 2 Statutory Regulations

Another appendix with changes due to other documents and version amendments.
Items 6 and 7 are now separate - caravan parks and theatres - previously these were combined in 6.
17 is new - the Construction of Products Regulation (CPR).

Appendix 3 OCPDs and RCDs

For maximum earth fault loop impedance values to acheive disconnection times, it is now suggested that 'where possible, designers should use the manufacturers specific data'.
Previous methods of calculation or the generic time/current graphs can still be used.
Several paragraphs of additional text have been added under 'RCDs:' prior to Table 3A.

Appendix 4 Current capacity and voltage drop

Although all of the tables from 4D1A onwards have changes highlighted, these are all due to minor items such as a.c. becoming AC and changes to spacing where % symbols are used.
The useless blank (not really) page 410 is still there.

Appendix 5 External influences

Note 2 on the first page now contains the key for use with the following tables. Previously this key was included under each table individually.
Most of the tables have various standards number changes, references, etc. All content is substantially similar.

Appendix 6 Model Forms

Minor Works Certificate

The full name of this model form has been corrected in a couple of places - 'minor electrical installation works certificate'. This is not new, but it was previously abbreviated in some of the text.
The model form has an extra section for circuit details, and the test results section has been expanded to include locations for most types of test result.
Notes for this certificate have the addition of 'notes for the person producing the certificate' although the text following that heading existed previously.

Electrical Installation Certificate

Minimal changes to this, the notes also have the additional heading 'notes for the person producing the certificate' but as with the MWC, the content following already existed.
One addition is the wording 'or the replacement of a consumer unit/distribution board' at the end of note 1.
Note 5 has 'schedules of inspections' added referring to page numbers and total number of pages.

Electrical Installation Condition Report

Notes have the addition 'not for the replacement of a consumer unit / distribution board'.
Note 12 is new - 'any deficiencies with intake equipment should be reported to the person ordering the work'.

Schedule of Inspections

A number of minor changes and amendments here, many of which are just where references to other regulations have different numbering.
External condition of metering equipment is now listed as' visual inspection only'.

Test Results

Appendix 8 Busbar trunking and powertrack

This contains a number of wording changes, with the main changes being to the rating factors for current carrying capacity.

Appendix 14 Determination of PFC

The previous contents of this appendix have been relocated to Appendix 3.
All of the content here is new, and concerns the determination of prospective fault current at relevant points of an installation.
Although a new appendix, the content and methods described are not new, this is just a compilation of information from elsewhere.

Appendix 16 Protection against Overvoltage

A minor change to the figures 16A2, 16A3, 16A4 - OCPDs are shown within the SPD assembly, previously shown as separate devices. Electrically there is no change.

Appendix 17 Energy Efficiency

All of this is new, and covers energy efficiency considerations when designing and installing an electrical installation.
Currently only five pages, but as the Scope states - 'it is intended that this appendix will be developed into Part 8 in a future amendment'.