IEC 61557-6:2019

Overview

IEC 61557-6:2019 is the international standard that defines requirements for measuring equipment used to test the effectiveness of residual current devices (RCDs) in low-voltage distribution systems (up to 1 000 V AC and 1 500 V DC) installed in TT, TN and IT systems. It covers the capabilities, tests and marking/operating instructions for instruments that perform regular disconnection tests of RCDs. This part of the IEC 61557 series is intended for test equipment - not for verifying RCDs against their product standards.

This third edition (2019) replaces the 2007 edition and introduces significant updates: requirements for testing a new RCD type, formal inclusion of type B RCD requirements, a new Annex B on recommended tripping times, and structural alignment with the wider IEC 61557 series.

Key topics and technical requirements

• Scope and application: Measurement equipment for effectiveness testing of RCDs in TT, TN and IT systems (not a product verification standard).
• Test functions: Requirements for tripping tests (measurement of trip current), non‑tripping tests, fault-voltage indication and measurement of trip time.
• Test waveforms: Use of sinusoidal or mains-derived quasi-sinusoidal test currents for tripping tests.
• Measurement categories: Equipment used on distribution systems must meet measurement category III (per IEC 61010-2-030); for electrical equipment use category II.
• Safety and probes: Test leads and probes must conform to IEC 61010-031.
• Accuracy and uncertainty: Clauses address operating uncertainty and calculation methods for measurement accuracy.
• Overvoltage and higher-voltage testing: Procedures and requirements for fault voltages exceeding nominal system voltage and overvoltage conditions.
• Marking & instructions: Mandatory marking, explicit indication of test-current waveform, and operating instructions for safe and correct use.
• Annexes: Normative Annex A for type B RCD measuring equipment and informative Annex B with recommended tripping times.

Practical applications

• Commissioning and periodic verification of RCD performance in commercial, industrial and residential low-voltage installations.
• Selection and design of portable RCD testers and multifunction installation testers by test-equipment manufacturers.
• Routine inspection and maintenance procedures for electricians, field service technicians and safety engineers.
• Creation of test procedures and checklists for electrical contractors, inspection bodies and asset managers concerned with electrical safety and compliance.

Who should use this standard

• Electrical test equipment manufacturers
• Electrical installers and commissioning teams
• Maintenance engineers and facility managers
• Inspection and certification bodies
• Safety and compliance professionals

Related standards

• IEC 61557-1 (general requirements for testing equipment)
• IEC/TR 60755, IEC 60947-2, IEC 61008, IEC 61009 (product and application references)
• IEC 61010 family (safety requirements for measurement equipment)

Keywords: IEC 61557-6, RCD testing, residual current devices, TT TN IT systems, low-voltage distribution, electrical safety, type B RCD, trip time, tripping tests.