It is essential to understand the limitations of the test instrument and product standard requirements when testing RCDs using the available RCD Type settings on the test instrument. A PEI is considered to be a low-voltage electrical installation connected (or not) to a public distribution network (the grid), able to operate with local power supplies (for example, PV panels or wind turbines), and/or with local storage units (for example, batteries). It monitors and controls the energy from the connected sources delivering it to current-using equipment (for example, motors, heating, lighting, and appliances such as washing machines, etc), and/or local storage units (for example, batteries), and/or the public distribution network. 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.

On-Site Guide (BS 7671:2018) (Electrical Regulations) (PDF) On-Site Guide (BS 7671:2018) (Electrical Regulations) (PDF)

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.”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. PD IEC/TR 62350:2006 Guidance for the correct use of residual current-operated protective devices (RCDs) for household and similar use. 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in the UK and it is now imperative that the industry is ready to work to this amendment before BS 7671:2018+A1:2020 is withdrawn.” As an accredited certification body, BSI Assurance cannot offer certification to clients where they have also received consultancy from another part of the BSI Group for the same management system. Likewise, we do not offer consultancy to clients when they also seek certification to the same management system. 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:

BS 7671 - 18th Edition - Institution of Engineering and

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. Each manufacturer’s instrument is different but changing the RCD Type is usually selected by pressing the relevant ‘function’ button on the instrument and the RCD Type symbol will change accordingly: see Figure 2. Most instruments will include a function to test general non-delayed and S Type time-delayed Type AC and Type A RCDs, some test instruments may also include a facility for testing other Types such as Type B RCDs.Further information on RCD operating and non-operating times can be found in the relevant product standards. Type A and Type AC RCCBs and RCBOs are manufactured to BS EN 61008 and BS EN 61009 respectively, whereas Type F and Type B RCCBs and RCBOs are manufactured to BS EN 62423. This is where knowledge of relevant product standards is essential, it would be reasonable to expect a 40 ms maximum disconnection time for a test at five times I Δn as would be the case with an AC test. However, this is not the case as the product standard BS EN 61008 requires a half wave pulsating residual current of 0.35 A (350 mA), see Table 4 extracted from BS EN 61008-1:2012+A2:23-1:2012+A11:2015. Regulation 443.4 for determining if protection against transient overvoltages is needed has been redrafted.