EN 60255-21-3:1995

Overview

EN 60255-21-3:1995 (CLC) is the European standard section that specifies seismic tests for measuring relays and protection equipment. It forms part of Part 21, which addresses vibration, shock, bump and seismic tests. The scope covers both electromechanical and static measuring relays and protection devices, with or without output contacts, and defines how seismic exposure is to be applied and how performance is to be verified after testing.

Key topics and requirements

• Scope and applicability - Applicable to measuring relays and protection equipment used in electrical power systems where seismic qualification is required.
• Test specimens and preparation - Guidance on the types of devices to be tested (electromechanical and static relays), required mounting and conditioning prior to testing.
• Seismic test procedures - Describes the general approach to apply seismic excitation to relays (horizontal/vertical mounting, excitation directions and durations) and the use of appropriate test equipment.
• Instrumentation and measurement - Requirements for monitoring input motion and device responses during testing to ensure controlled, repeatable seismic input.
• Post‑test checks and acceptance - Criteria for evaluating relay functionality and performance after seismic exposure, including mechanical integrity and electrical operation.
• Documentation and reporting - Expectations for test records, measured data, and conformity statements to demonstrate compliance.

(Note: EN 60255-21-3:1995 sets test intent and procedures; specific numerical levels or frequencies should be confirmed from the official standard text.)

Applications and who uses it

• Relay and protection equipment manufacturers use this standard to design and qualify products for seismic resilience and produce test evidence for market acceptance.
• Independent test laboratories implement the specified seismic procedures to certify devices for compliance with European requirements.
• Power utilities and grid operators reference the standard when specifying equipment for seismic-prone installations to ensure reliable protection performance after earthquakes.
• Procurement and compliance teams include EN 60255-21-3 requirements in tender documents to ensure delivered relays meet seismic robustness expectations.

Related standards

• Other sections of Part 21 cover vibration, shock and bump tests for relays and protection equipment and should be consulted together with Section 3 when assessing overall mechanical resilience.
• For complete test levels, mounting details and pass/fail criteria always refer to the full official EN 60255-21-3 document issued by the CLC.

Keywords: EN 60255-21-3:1995, seismic tests, electrical relays, measuring relays, protection equipment, relay testing, vibration shock bump, seismic qualification, electromechanical relays, static relays.