IEC 61643-11:2025

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.
This edition includes the following significant technical changes with respect to the previous edition:
a) Specific requirements for SPDs for AC applications are now contained in this document, whereas the common requirements for all SPDs are now contained in IEC 61643-01;
b) Clarification on test application either to a complete SPD, to a "mode of protection", or to a complete "SPD assembly";
c) Additional measurement of voltage protection level on "combined modes of protection" between live conductors and PE;
d) Additional duty test for T1 and T2 SPDs with follow current to check variation of the follow current value at lower impulse currents;
e) Modified and amended short circuit current test requirements to better cover up to date internal SPD disconnector technologies;
f) Improved dielectric test requirements for the SPD's main circuits and added dielectric test requirements for "electrically separated circuits";
g) Additional clearance requirements for "electrically separated circuits".
The requirements of this document supplement, modify or replace certain of the general requirements contained in IEC 61643-01 and shall be read and applied together with the latest edition of IEC 61643-01, as indicated by the undated normative reference in Clause 2 of this document.