Overview
IEC 61138:2007 is an international standard developed by the International Electrotechnical Commission (IEC) that specifies requirements for cables used in portable earthing and short-circuiting equipment. This standard applies to flexible cables insulated with ethylene propylene rubber (EPR), polyvinyl chloride (PVC), or silicone rubber (SiR). Unlike general-purpose electrical cables, these cables are exclusively designed for earthing and short-circuiting applications, and therefore no rated voltage is assigned.
The standard provides detailed specifications regarding the construction, material properties, marking, and testing methods for these cables to ensure safety, flexibility, and durability in demanding electrical environments. The third edition of IEC 61138 includes important updates such as the inclusion of silicone rubber insulation and a new clashing test annex.
Key Topics
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Cable Construction
The standard defines general construction requirements for conductors, insulation, and separators. Conductors must meet strict material and electrical resistance criteria, while insulation materials are required to demonstrate mechanical resilience and stability before and after ageing.
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Insulation Materials
Insulation options include ethylene propylene rubber (EPR), polyvinyl chloride (PVC), and silicone rubber (SiR), each selected for their electrical and mechanical properties relevant to earthing and short-circuiting equipment.
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Marking and Identification
Cables must be clearly marked with origin, code designation, and cross-sectional area to facilitate identification and ensure compliance with safety regulations.
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Testing Procedures
IEC 61138:2007 prescribes rigorous testing protocols based on related IEC standards: IEC 60227-2, IEC 60245-2, IEC 60811, and IEC 62230. Tests include electrical properties verification (voltage and spark tests), overall diameter measurement, flexibility assessments, and the innovative clashing test for mechanical impact resistance.
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Code Designations and Types
Particular cable types and their code designations are laid out in clause 6, helping manufacturers and end-users select appropriate cables for specific portable earthing and short-circuiting applications.
Applications
IEC 61138 compliant cables are critical in ensuring the safety and protection of electrical personnel and equipment by effectively grounding and short-circuiting electrical systems during maintenance or fault conditions. Key applications include:
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Live Working and Electrical Maintenance
Providing reliable grounding paths to protect workers dealing with live electrical circuits.
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Fault Protection and Short-Circuiting
Enabling quick and safe short-circuiting in industrial electrical installations to prevent equipment damage and hazards.
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Portable Earthing Equipment
Utilized in scenarios requiring flexible, durable cables that can withstand mechanical stresses and environmental factors during repeated handling and use.
By adhering to IEC 61138, manufacturers produce cables that meet international safety standards, ensuring compatibility and trustworthiness in portable earthing and short-circuiting devices globally.
Related Standards
IEC 61138 references multiple complementary IEC standards to support testing and material specifications, including:
- IEC 60227-2: Test methods for polyvinyl chloride insulated cables
- IEC 60245-2: Test methods for rubber insulated cables
- IEC 60811: Common test methods for insulating and sheathing materials of cables
- IEC 62230: Additional cable testing procedures
- IEC 61230: Live working – Portable equipment for earthing or short-circuiting (for the complete equipment requirements)
These related standards provide comprehensive guidelines that ensure cables meet the rigorous performance, safety, and quality requirements needed in electrical protection applications.
Keywords: IEC 61138, portable earthing cables, short-circuiting cables, flexible insulated cables, EPR insulation, PVC insulation, silicone rubber cable, electrical safety standards, live working equipment, cable testing methods
