IEC 61000-4-5:2014 relates to the immunity requirements, test methods, and range of recommended test levels for equipment with regard to unidirectional surges caused by over-voltages from switching and lightning transients. Several test levels are defined which relate to different environment and installation conditions. These requirements are developed for and are applicable to electrical and electronic equipment. The object of this standard is to establish a common reference for evaluating the immunity of electrical and electronic equipment when subjected to surges. The test method documented describes a consistent method to assess the immunity of an equipment or system against a defined phenomenon. This standard defines a range of: - test levels; - test equipment; - test setups; and - test procedures. The task of the described laboratory test is to find the reaction of the equipment under test (EUT) under specified operational conditions to surge voltages caused by switching and lightning effects. It is not intended to test the capability of the EUT's insulation to withstand high-voltage stress. Direct injections of lightning currents, i.e. direct lightning strikes, are not considered in this standard. This third edition cancels and replaces the second edition published in 2005, and constitutes a technical revision which includes the following significant technical changes with respect to the previous edition: - a new Annex E on mathematical modelling of surge waveforms; - a new Annex F on measurement uncertainty; - a new Annex G on method of calibration of impulse measuring systems; and - a new Annex H on coupling/decoupling surges to lines rated above 200 A. Moreover while surge test for ports connected to outside telecommunication lines was addressed in 6.2 of the second edition (IEC 61000-4-5:2005), in this third edition (IEC 61000-4-5:2014) the normative Annex A is fully dedicated to this topic. In particula...