Stroma Certification provides 18th Edition guidance for inspectors working in the inspection and testing fields.
The publication of the 18th Edition has seen significant changes to Part 6 Inspection and Testing, mostly in the layout and numbering of the regulations. There are also some subtle changes to some of the test procedures.
New chapter structure
Firstly, Chapter 61 (Initial Verification), Chapter 62 (Periodic Inspection and Testing) and Chapter 63 (Certification and Reporting) have been deleted and replaced by two new chapters. These are Chapter 64 (Initial Verification) and Chapter 65 (Periodic Inspection). Most of the content of the previous 17th Edition Regulations has been renumbered and integrated in to the new chapters.
In the new Chapter 64 there are some minor changes and some wording changes to the items to be inspected but nothing more demanding than the 17th Edition.
643.2.1 – Initial Verification Testing
A subtle change for Initial Verification testing is that there is now a requirement in 643.2.1 to measure the earth continuity of protective conductors, connections to exposed and extraneous conductive parts and ring final circuit conductors.
Previous editions of BS 7671 only required continuity to be proved with a device between 4-24V at 200mA so a battery and bell set could be used. Most inspectors will nearly always use an instrument to do this test so it doesn’t present much of an impact on industry practice.
Regulation 643.7.1 – Fault Protection
There is a subtle but significant change in Regulation 643.7.1 which concerns itself with Fault Protection where this relies on an RCD for both TN and TT systems. It is important to note this new provision does not apply where an over current device is installed for Fault Protection.
The new provision says: “Where the effectiveness of the protective measure has been confirmed at a point located downstream of an RCD, the protection of the installation downstream from this point may be proved by confirmation of the continuity of the protective conductors”.
This means that provided earth continuity has been proved, which it should have been if the tests have been correctly applied in the required sequence, and the RCD protecting the circuit or circuits has been tested satisfactorily anywhere downstream of the RCD then earth loop impedance testing is not required.
This is a significant change and would require ‘N/A’ to be entered for the EFLI test on the appropriate box on the Electrical Installation Certificate. The disconnection time indicated by the test should comply with the requirements of Chapter 41.
RCDs and Additional Protection
There is another significant change to RCD testing where the RCD is installed for Additional Protection. It is important that inspectors are able to determine the differences for Fault Protection, Additional Protection and Fire Protection when RCDs are installed for these purposes. Regulation 643.8 requires that the instrument used complies with BS EN 61557-6.
There is a ‘Note’ to this regulation and it is important to recognise that Notes to Regulations only provide guidance and are not regulations.
The Note says: “Effectiveness is deemed to have been verified where an RCD meeting the requirements of Regulation 415.1.1 disconnects within 40 ms when tested at a current equal to or higher than five times its rated residual operating current”.
The model forms in Appendix 6 have been changed so there is now only one box to record the highest disconnection time for an RCD test. Stroma recognises that this new provision may cause confusion in the industry and advises that where RCDs are provided for Additional Protection, inspectors should carry out X1 and X5 tests and record the highest disconnection time measured on the new form.
New provisions in 651.2
For Periodic Inspection and Testing there are two new provisions added to the previous list of items to be confirmed in Regulation 651.2. These are:
(iii) confirmation of correct rating and setting of protective devices required by Chapter 41;
(iv) confirmation of correct rating and setting of monitoring devices.
These new provisions state what a competent inspector would do anyway when carrying out a periodic inspection and test.
Appendix 6 model forms
The model forms in Appendix 6 have been updated for both Initial Verification and Periodic Inspections. There is now a new column on the Schedule of Test results to indicate the voltage applied to circuits when carrying out insulation resistance testing.
It is assumed that 500V testing will be substituted for a 250V test with increasing numbers of installations having electronic controls installed. A Smart Home insulation test at 500V may no longer be very smart!
In addition, there is now a column for recoding the operation of the test button on any Arc Fault Detection Devices (AFDDs).
There is a change to the standard label in Part 5 that now has a new label advising the user to test RCDs every six months, as opposed to quarterly. Stroma believes that this change may cause a considerable debate in the industry and advises that contractors’ stocks of the old-style labels are used before January 2019.
For more information on the 18th Edition, including training courses from Stroma, visit: www.stroma.com/18th-edition