lEC 60320-1:2021 sets the general requirements for appliance couplers for two poles and two poles with earth contact and for the connection of electrical devices for household and similar onto the mains supply. This document is also valid for appliance inlets/appliance outlets integrated or incorporated in appliances. This fourth edition cancels and replaces the third edition published in 2015 and Amendment 1:2018. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: introduction of necessary tolerances throughout this document; the heating test from edition 2 is reintroduced in 18.2; temperature rise added for plug connectors in Clause 21; change for better readability in 23.3; updated lateral pull test in 23.6 for connectors/plug connectors with separate front parts; revision of 24.1 for ball pressure test; Clause 27 for glow wire test is updated; revision of Annex C for test sequences; additional Annex E for additional tests and requirements for appliance couplers intended to be used in ambient temperatures above +35 °C.