of negligence or any other cause. Where reference is made to legislation it is not to be considered 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. Amendment 2 is an essential update to provide for the safety of electrical installations in the UK and it is now imperative that the industry is ready to work to this amendment before BS 7671:2018+A1:2020 is withdrawn.” Arcs can be caused by insulation defects in cables, damage to cables by impact and penetration of nails and screws, loose terminal connections, and so on. An AFDD is designed to operate (trip) when a dangerous arc is detected by analysing the signature of the arc. Switching arcs caused by fluorescent lighting, for example, should not cause an AFDD to operate. AFDDs can be installed in distribution boards and consumer units to protect final circuits and should be installed in accordance with the manufacturer’s instructions. When installing components from a different manufacturer to that of the existing equipment in a distribution board or consumer unit, it is important to seek advice from the manufacturer that the new equipment is suitable and compatible. Some test instruments have a variable trip current setting, if a tripping current of 50 mA at five times I Δn was selected on the Type A setting, a trip current of 350 mA could be simulated (50 x 5 x 1.4 = 350 mA). However, the variable test current feature is not available on all test instruments.

IET and BSI publish Amendment 2 (2022) to BS 7671:2018 (IET

If you think you may have a faulty RCD, firstly ensure there are no factors within the installation that are influencing the results. Always carry out RCD testing in accordance with industry guidance and manufacturer’s instructions.Similarly, for instruments with a setting for Type B RCDs a multiplier of two times I Δn is applied as required by the product standard, BS EN 62423:2012 Type F and type B residual current operated circuit-breakers with and without integral overcurrent protection for household and similar uses. Through its expertise in Standards and Knowledge, Assurance Services, Regulatory Services and Consulting Services, BSI helps clients to improve their performance, grow sustainably, manage risk and ultimately become more resilient. BS 7671:2018+A2:2022 Requirements for Electrical Installations, IET Wiring Regulations, 18 th Edition.

On-Site Guide (BS 7671:2018+A2:2022) (Electrical Regulations)

Dan Palmer, Associate Director of Committees at BSI said: “BS 7671 is one of the UK’s most important standards, providing authoritative requirements to promote electrical safety. The changes introduced in this new amendment will help electrical professionals keep up to date with new and innovative technologies, as well as ensuring they have current knowledge about designing safe installations.”

The requirements for testing RCDs have been simplified, a single test is all that is required to show compliance with the minimum requirement laid out in BS 7671:2018+A2:2022. Regardless of RCD type, the test is carried out using an alternating test current, applied at the RCD’s rated residual operating current I Δn, the maximum disconnection time is expected to be less than 300ms for a general non-delay type RCD. For S type time-delayed RCDs, the operating time should be 130 - 500 ms. Other kinds of RCD testing may be useful for fault finding purposes. Whilst BS 7671:2018+A2:2022 doesn’t require other types of RCD testing, however additional tests are not precluded and may be useful for fault finding purposes, these tests could include: NOTE: It is essential to liaise with the distribution network operator (DNO) when planning embedded generator installations. Relevant documents include the Electricity Safety, Quality and Continuity Regulations (ESQCR) 2002, Engineering Recommendation G98, Engineering Recommendation G99 and the Distribution Code. More information is available from the Energy Networks Association (ENA). Conclusion