CLC/TC 64/WG 02 - Wiring systems - Protective measures against thermal effects, overcurrent

IEC 60364-4-43:2023 provides requirements for: - protection of live conductors, PEN conductors, PEM conductors, and PEL conductors against the harmful effects caused by overcurrent; - coordination of measures for protection against overcurrent. This fourth edition cancels and replaces the third edition published in 2008. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: a) the standard has been restructured, see Table 1 (Correspondence between IEC 60364‑4‑43:2008 and this document) below; b) the measure "automatic disconnection of supply" has been designated as the preferred measure for protection against overcurrent; c) all measures except the measure "automatic disconnection of supply" have been transferred into new normative annexes to indicate that these measures are usable in certain applications and under certain restricted conditions only (see Annex A, Annex B and Annex E); d) a new clause "Terms and definitions" has been added; e) new requirements have been added for the protection of the neutral or mid-point conductor (with and without triplen harmonics).

NEXT ACTION: TC action by 2021-11-01
2021-06-24 MDC: Document on hold awaiting BT approval of A-deviations
2019-10-01: upcoming CLC/TC 64 request to CLC/BT to proceed with a second formal vote.

IEC 60364-4-42:2010 applies to electrical installations with regard to measures for the protection of persons, livestock and property against: - thermal effects, combustion or degradation of materials, and risk of burns caused by electrical equipment, - flames in case of a fire hazard being propagated from electrical installations to other fire compartments segregated by barriers which are in the vicinity, and - the impairment of the safe functioning of electrical equipment including safety services. This third edition cancels and replaces the second edition, published in 2001, and constitutes a technical revision. The main changes with respect to the previous edition are listed below: - The scope now includes protection against all thermal effects and flames in case of a fire hazard being propagated from electrical installations to other fire compartments segregated by barriers which are in the vicinity. - Requirements associated with escape routes for evacuation in an emergency have been expanded/modified. - Requirements associated with the nature of processed or stored materials have been expanded/modified. - Requirements associated with combustible constructional materials have been expanded/modified. - Requirements associated with fire propagating structures have been modified slightly. - New requirements for the selection and erection of installations in locations which might endanger precious goods have been added. - Protection against overheating now includes space heating appliances.