10.99 New project approved Feb 26, 2026
CENELEC
CLC/TC 37A Low voltage surge protective devices
European Norm
This document, together with IEC 61643-01, is applicable to devices for surge protection against indirect and direct effects of lightning or other transient overvoltages.
These devices are intended to be connected to AC power circuits and equipment rated up to 1 000 V RMS, the preferred frequencies taken into account in this document are 50/60 Hz.
Other frequencies are not excluded. Performance and safety requirements, tests and ratings are specified in this document. These devices contain at least one nonlinear component and are intended to limit surge voltages and divert surge currents.
The test requirements provided by this document are based on the assumption that the SPD is connected to an AC power circuit fed by a power source providing a linear voltage-current characteristic. When the SPD is to be connected to a different kind of source or to a different
frequency, careful consideration is required. This mainly applies with regard to system and fault conditions to be expected in such a system (e.g. expected short circuit current, TOV-stresses).
This document can apply for railway applications, when related product standards do not exist for that area or for certain applications.
Based on a risk assessment it might not be necessary to apply all requirements of this document to SPDs designed for specific power applications only, e.g. circuits with a low power capability, circuits supplied by nonlinear sources, circuits with protective separation from the utility supply.
Legislation related to this standard
Directive 2014/35/EU of the European Parliament and of the Council of 26 February 2014 on the harmonisation of the laws of the Member States relating to the making available on the market of electrical equipment designed for use within certain voltage limits
PUBLISHED
EN IEC 61643-11:2025
IN_DEVELOPMENT
EN IEC 61643-11:2025/prAB
10.99
New project approved
Feb 26, 2026