May June 2020 Electric.ie Magazine

ELECTRIC.IE • The Magazine & Website for the Irish Electrical Industry • 27 2. public services and cultural heritage, e.g. loss of public services, IT centres, museums; commercial or industrial activity, e.g. hotels, banks, industries, commercial markets, farms, a large number of individuals, e.g. large buildings, offices, schools. For other cases a risk assessment is required to be performed. Should a risk assessment not be performed then protection against transient overvoltage is required.” Single dwelling units however require an assessment as to whether the total value of the installation and equipment therein justifies the inclusion of such protection. 531.3.3 Types of RCDs “RCD types AC are not recommended in new electrical installations. - RCD Type AC: RCD tripping on alternating sinusoidal residual current, suddenly applied or smoothly increasing. – RCD Type A: RCD tripping on alternating sinusoidal residual current and on residual pulsating direct current, suddenly applied or smoothly increasing. – RCD Type F: RCD for which tripping is ensured as for Type A and in addition: i) for composite residual currents, whether suddenly applied or slowly rising intended for circuit supplied between phase and neutral or phase and earthed middle conductor; ii) for residual pulsating direct currents superimposed on smooth direct current. – RCD Type B: RCD for which tripping is ensured as for Type F and in addition: a) for residual sinusoidal alternating currents up to 1 000 Hz; b) for residual alternating currents superimposed on a smooth direct current; c) for residual pulsating direct currents superimposed on a smooth direct current; d) for residual pulsating rectified direct current which results from two or more phases; e) for residual smooth direct currents whether suddenly applied or slowly increased independent of polarity.” RCDs exist in various different forms and react differently depending on the presence of DC components or different frequencies, and these are outlined in Clause 531.3.3. To fully comply with this clause it is essential to select the correct type of RCD for the application. Distribution Boards in domestic premises Clause 530.6.1 General “Distribution boards (switchgear assemblies) shall comply with I.S. EN 61439-1. Distribution boards and similar switchgear assemblies within domestic (household) premises, shall comply with I.S. EN 61439-3 and shall: i) have their enclosure manufactured from metallic or non- metallic materials complying with IEC 60695-2-11:2000, and the enclosure should be sized to take account of the equipment contained within, and the resulting internal ambient temperature rise, as per I.S. EN 61439-1.” In order to fully comply with Clause 530.6.1 it is essential that the enclosure materials used in domestic consumer units meet the glow-wire test requirements of IEC 60695-2-11, also the dimensions of the assembly, and the layout of the internal components, must meet the ambient temperature rise requirements of I.S. EN 61439-1. Assemblies conforming to these harmonised standards should be CE marked. The I.S.10101 standard is the first major revision to the wiring regulations in over 10 years, and is based on the IEC Harmonised document IEC 60364 for the safety of electrical installations. Full copies of the new standard can be ordered online from NSAI. For further information visit our IS:10101 Regs Hub at www.hager.ie IS:10101 Bitesize Guide