IEC 61643-11:2025 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.
NOTE 1 More information on risk assessment is provided in IEC Guide 116.
NOTE 2 Other exclusions based on national regulations are possible.