Overview
IEC 60684-3-248:2007 is an international specification for general purpose, heat‑shrinkable, dual‑wall polyolefin sleeving used as flexible electrical insulation. It defines six sleeving types with nominal shrink ratios 2:1, 3:1 and 4:1, and covers both low‑temperature and high‑temperature adhesive inner walls (suitable up to 105 °C and 125 °C respectively). The sleeving comprises a cross‑linked polyolefin outer layer and a hot‑melt adhesive inner wall that flows during shrinking to form a protective seal.
Key topics and requirements
- Types and sizes: Three shrink ratios with type codes AL/AH (2:1), BL/BH (3:1), CL/CH (4:1). The standard lists typical expanded/recovered internal diameters and dimensional limits.
- Adhesive classes: Low‑temperature (L) and high‑temperature (H) meltable inner walls, with defined suitability temperatures (105 °C and 125 °C).
- Material construction: Outer flexible cross‑linked polyolefin; inner hot‑melt adhesive for bonding and environmental sealing.
- Performance tests and limits: Dimensional tolerances, wall and meltable‑wall thickness, electrical breakdown voltage, resistance to selected fluids, flame‑retardant behavior and elevated temperature performance (including a stepped‑mandrel test and conditioning protocols).
- Test conditions: Example conditioning: recovery in a forced‑air oven for (5 ± 1) min at 200 °C ± 5 K prior to many tests; elevated temperature performance uses recovery on a stepped mandrel and oven conditioning per the standard.
- Conformance: Typical conformance testing is based on specific nominal sizes and black sleeving samples; colour fastness to light is required for non‑black colours.
- Normative references: IEC 60684‑1 (general) and IEC 60684‑2 (test methods), IEC 60757 (colour codes) and ISO 1817 (fluid effects).
Applications
- Insulating and environmental sealing of wire joints and terminations
- Strain relief and abrasion protection for harnesses and cables
- Protection in automotive, marine, aerospace, telecommunications, appliance and industrial electrical assemblies
- Situations requiring flame‑retardant, adhesive‑lined heat‑shrink tubing with defined shrink ratios and temperature ratings
Who uses this standard
- Cable and heat‑shrink tubing manufacturers for product specification and quality control
- Test laboratories and compliance engineers verifying dimensional, electrical and thermal performance
- OEMs, procurement and design engineers specifying sleeving for harnesses and assemblies
- Maintenance and installation teams selecting appropriate heat‑shrink materials for repairs
Related standards
- IEC 60684‑1: Definitions and general requirements for flexible insulating sleeving
- IEC 60684‑2: Methods of test for sleeving
- IEC 60757: Colour designation codes
- ISO 1817: Testing resistance to fluids
Keywords: IEC 60684-3-248, heat-shrinkable sleeving, dual wall polyolefin, flame retarded, shrink ratio, adhesive inner wall, heat shrink tubing, flexible insulating sleeving.
Open preview (PDF)Flexible insulating sleeving - Part 3: Specifications for individual types of sleeving - Sheet 248: General purpose, heat-shrinkable, dual wall polyolefin sleeving, flame retarded, shrink ratios 2:1, 3:1, 4:1
