Abstract
       IEC 61000-4-23:2016(E) provides a protective devices test method for HEMP and other radiated disturbances. It is primarily intended for HEMP testing but can be applied to other externally generated radiated disturbances where appropriate. It provides a brief description of the most important concepts for testing of shielding elements. For each test, the following basic information is provided:
       - theoretical foundation of the test (the test concepts);
       - test set-up including outside-to-in and inside-to-out measurements;
       - required equipment;
       - test procedures;
       - data processing.
       This international standard does not provide information on requirements for specific levels for testing. Due to the available space, a transmitting antenna position outside the barrier has mainly been suggested. However, nowadays, many EMP protection facilities in practical use do not actually have enough space available outside the electromagnetic barrier due to physical constraints such as concrete walls or soil to allow the method described in IEC 61000-4-23:2000 (edition 1) to be applied correctly. From experience many facilities have available space for a 1 m separation or less only. Therefore, in many practical cases it is not possible to measure shielding effectiveness according to the test method of previous documents. The constructors for EMP protection facilities are also unwilling to build facilities with extra space for measurements with the transmitting antenna outside the barrier due to the great expense and inefficiency of the operational working area for new or existing buildings. This document provides additionally a method that allows the transmitting antenna to be placed inside the enclosure and the receiving antenna outside the barrier ('inside-to-out' method). Annex F includes test set-up and procedure examples. This second edition cancels and replaces the first edition published in 2000. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
       a) updates to the shielding effectiveness (SE) test method in Clause 5;
       b) a new Annex F describing methods for testing 'inside-to-out' has been added.