This part of IEC 1000‑5 defines how protective devices for conducted disturbance proposed for HEMP protection shall be specified. It is intended to be used for the harmonization of existing or future specifications issued by protective device manufacturers, electronic equipment manufacturers, administrations and other ultimate buyers. Performance requirements shall be given in future IEC documents.

This section covers protective devices currently being used for protection against induced HEMP transients on signal and low voltage power lines (nominal voltage up to 1 kV a.c.).

General information can be applied also to high voltage lines. However, in these cases, the additional requirements for the protection levels of existing lightning arresters (especially gapless MO-arresters) are under consideration.

In general, HEMP-relevant parameters, i.e. parameters related to very fast changes of electromagnetic field, voltage (u) and current (i) as a function of time, are of interest. For basic specifications, reference is made to other relevant standards (see annex E) dealing with phenomena other than HEMP. When such standards do not adequately consider the requirements of modern electronics, additional specifications, modifications or extensions based on non-HEMP-relevant standards are defined.