prEN IEC 60255-21:2026

This part of IEC 60255 specifies the withstand levels and associated tests for vibration response, broadband random vibration, shock response, shock withstand, bump, and seismic tests applicable to measuring relays and protection equipment. The purpose of these tests is to prove the capability of a measuring relay or protection equipment to withstand conditions of vibration, shocks, and bumps encountered in service, during transportation unpackaged in final arrangement e.g. relays mounted in cubicle. They also demonstrate the capability of a measuring relay or protection equipment to perform its required function during and after the time it is subjected to the stresses and displacements resulting from an earthquake. To claim compliance a product shall meet all tests specified in this document.
All measuring relays and protection equipment used for protection within the power system environment are covered by this document. Other documents in this series can define their own requirements which in such cases take precedence. The measuring relays and protection equipment are generally located close to the electrical installations to be protected: power stations, substation, and industrial buildings.
Measuring relays and protection equipment installed in special applications (marine, railways, aerospace, explosive atmospheres, computer centres, etc.) could have additional requirements required by that application.
The requirements specified in this document are applicable to measuring relays and protection equipment in a condition representative of how new equipment is provided by the manufacturer.
All tests in this document are type tests, unless otherwise declared. As each category of test has a unique procedure and requirements, the below details are also provided.