ISO 8820-5:2015

Overview

ISO 8820-5:2015 specifies fuse‑links with axial terminals (strip fuse‑links) - Types SF 30 and SF 51 - and the associated test fixtures for use in road vehicle electrical systems. The part defines rated voltages, current ratings, physical dimensions, marking/colour coding, and the test procedures and performance requirements needed to verify safe operation. It is applicable to fuse‑links with a rated voltage of 32 V, current ratings from 30 A to 500 A, and a breaking capacity of 2 000 A, intended for vehicles with nominal 12 V and/or 24 V electrical systems.

Key topics and technical requirements

• Rated parameters: Rated voltage 32 V; current range 30–500 A; breaking capacity 2 000 A.
• Types covered: Strip fuse‑links Type SF 30 and SF 51 including dimensional specifications and designation examples (Clause 6).
• Test program: Prescribes test sequences and sample groups for dimensional checks, marking, terminal strength, voltage drop, transient current cycling, climatic/chemical/mechanical loads, operating‑time tests, current steps and breaking capacity (Clauses 5 and Table 2).
• Voltage drop: Specifies measurement points and maximum voltage‑drop limits for rated currents to define energy dissipation and temperature rise.
• Transient current cycling: Defines pulse sequences to evaluate tolerance to transient energy; note this test does not apply to SF 30 ≥150 A and SF 51 ≥300 A (agreement between supplier/manufacturer required for those sizes).
• Terminal and connection requirements: Test fixture connection resistance limits: maximum 1.0 mΩ for SF 30 and 0.35 mΩ for SF 51 to ensure proper test performance. Terminals must have corrosion‑protective finish and adequate mechanical/electrical properties.
• Special use note: SF 30 at 150–200 A and SF 51 at 300–500 A are intended only for short‑circuit protection and require cables with insulation able to withstand test stresses.
• Test cables and materials: Test cable sizes and conductor material requirements are specified (see Clause 5 and Table 3), with conductor material referenced to ISO 6722.
• Colour coding and marking: Standardizes marking and colour coding for current ratings to aid identification.

Practical applications - who uses this standard

• Automotive OEMs and electrical system designers specifying protective devices.
• Fuse manufacturers and component suppliers developing SF 30 / SF 51 strip fuses.
• Test laboratories and certification bodies performing conformity and performance testing.
• Aftermarket and repair suppliers ensuring replacement parts meet vehicle safety requirements.
• Electrical engineers validating short‑circuit protection, voltage drop and transient performance in 12 V / 24 V vehicle systems.

Related standards

• ISO 8820-1: Definitions and general test requirements (used in conjunction with this part).
• ISO 8820-2: User guidelines.
• ISO 6722: Conductor material specification for test cables.

Keywords: ISO 8820-5, SF 30, SF 51, strip fuse-links, automotive fuses, road vehicles, test fixtures, voltage drop, breaking capacity, transient current cycling.