Overview
IEC 61557-10:2024 is Part 10 of the IEC 61557 series addressing combined measuring equipment used for testing, measuring and monitoring protective measures in low-voltage distribution systems (up to 1 000 V AC and 1 500 V DC). The standard specifies safety, performance and marking requirements for devices that integrate multiple measuring functions (for example insulation, loop/earth/phase checks and RCD tests) into a single instrument. It also covers combined devices that mix IEC 61557 functions with other measurement functions.
Key topics and requirements
- Scope and definition: Defines “combined measuring equipment” and ensures compatibility with the other parts of the IEC 61557 series.
- Safety under extraneous overvoltage: Specifies the required extraneous overvoltage withstand capability for terminals and combinations of functions (Table 1). Examples in the document include test levels like 1.2 × U for AC extraneous overvoltage with defined durations (e.g., 10 s) and reduced levels (1.1 × phase-to-phase) when appropriate markings/pictograms are present.
- Performance after stress: Requirements on functional performance and absence of user hazards after application of specified overvoltages.
- Design and terminals: Clarifies which terminals must be tested (exemptions for clearly non-test terminals and terminals accessible only with a tool) and addresses reasonably foreseeable misuse.
- Marking and instructions: Requires clear marking and pictograms indicating maximum distribution system voltage and other safety information so users can apply the correct test settings.
- Test considerations: Test procedures and test source characteristics (updated to reflect expected short‑circuit currents and measurement categories per IEC 61010-2-030).
Applications and users
IEC 61557-10:2024 is directly relevant for:
- Manufacturers of portable and bench combined measuring instruments who must demonstrate compliance and safe operation.
- Electrical test equipment designers integrating multiple protective-measure tests into one device.
- Electrical safety engineers, installers and maintenance technicians who select and use combined testers for commissioning and periodic verification of low-voltage systems.
- Certification and conformity assessment bodies that verify product compliance with the IEC 61557 series.
Practical benefits include simplified field workflows (one instrument for multiple tests), clear safety guidance for mixed-function devices, and improved user protection against accidental overvoltage.
Related standards
Keywords: IEC 61557-10:2024, combined measuring equipment, extraneous overvoltage, low voltage distribution systems, protective measures, testing measuring monitoring.