Following the release of the 18th Edition Amendment 2 published on 28th March, we have put together a guide to provide everything you need to know on the following areas: Type AC RCDs are affected by residual DC components and can become desensitized or ‘blinded’ and may not operate within the required time or, in some instances, may not operate at all. Table 1 summarizes the various types of RCD referred in BS 7671:2018+A2:2022 and their resilience to DC components.

David Garrett, Product Management Manager at Deta, says “This is a reminder that the regulations affecting consumer units become mandatory on 28th September, and that all designers, developers and installers should be mindful that they need to be compliant from this date. Deta can assist in providing related information and product solutions to match your needs.”For ‘S’ Type time-delayed RCDs, the operating time shall be between 130 ms (minimum) and 500 ms (maximum). S Type time-delayed RCDs are not applicable for additional protection, hence, the operating times are not included in Regulation 643.8. The presence of SPDs in an installation shall be indicated by an information notice at or near the relevant distribution board(s).

When verifying whether an RCD can provide additional protection care must be taken to ensure that the device is tested at a test current appropriate to the operating characteristic to which the device was designed.Note 1: Completion of an electrical installation designed to the withdrawn standard can be subject to the contractual agreement between all parties involved. Existing installations that have been installed in accordance with earlier editions of the Regulations may not fully comply with Amendment 2 requirements. This does not necessarily mean that they are unsafe for continued use or require upgrading. However, work carried out on an existing installation will need to meet the requirements of Amendment 2 after 27th September 2022. There is no longer a requirement to perform a test using a test current equal to or higher than five times the rated residual current. What is an alternating current test? This applies to the RCD test label, periodic test label, presence of SPD label (new requirement). The only exception is the warning notice of additional supplies which, if required, will still need to be present on the enclosure. It has been reported that contractors have experienced difficulties when testing 30 mA RCDs having a 0.25 A residual operating current characteristic. These difficulties seem to stem from the devices being tested at a current of 150 mA, rather than the necessary 250 mA (0.25 A), based on the assumption that using a test current of 5 I Δn will always be sufficient to cause the device to operate within the required time (0.04 s). This is not the case. A house in multiple occupation is a property rented out by at least three people who are not from one “Household” but share facilities like a bathroom or kitchen.

BS EN IEC/IEEE 82079-1:2020 Preparation of information for use (instructions for use) of products. Principles and general requirements A fire or smoke detection system would fall into this definition. If this system is supplied from the electrical installation then an overvoltage could cause it to fail and, as such, requires protection. The simplest way to provide this protection may be to supply it at the distribution board or consumer unit. Indent (ii) however requires the use of overvoltage protection devices to protect a Safety Service. This is defined in Part 2 as; “An electrical system for electrical equipment provided to protect or warn persons in the event of a hazard, or essential to their evacuation from a location.”The verification of the effectiveness of the measures applied for additional protection is fulfilled by visual inspection and testing. Where RCDs are required for additional protection, the effectiveness of automatic disconnection of supply by RCD’s shall be verified using suitable test equipment according to BS EN 61557-6 (see Regulations 643.1) to confirm that the relevant requirements of Chapter 41 are met. This installation, or part of it, is protected by a device which automatically switches off the supply if an earth fault develops. Test six monthly by pressing the button marked ‘T’ or ‘Test’. The device should switch off the supply and should then be switched on to restore the supply. If the device does not switch off the supply when the button is pressed, seek expert advice. This time, Amendment 1 is withdrawn on 27th September 2022 to bring BS 7671 into line with other British Standards when they are reviewed. 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. The testing should be carried out in both the positive and negative half-cycles and the result obtained in each case should not exceed 40 ms; the greater of the two results obtained should be recorded in the appropriate place on the schedule of test results.