ISO 8820-12:2020

Overview

ISO 8820-12:2020 defines requirements for fuse-links with tabs (blade-type) Type N (sub‑miniature) intended for road vehicles. The standard covers rated currents up to ≤30 A, a rated voltage of 32 V, and a minimum breaking capacity of 1 000 A. It specifies dimensions, marking and colour coding, test procedures, performance limits and pass/fail criteria tailored to this blade‑type automotive fuse. ISO 8820-12 is to be used alongside ISO 8820‑1 and ISO 8820‑2.

Key topics and requirements

• Scope & designation
  • Applies to Type N (sub‑miniature) blade fuse‑links for road vehicles (example designation: Fuse‑link ISO 8820 - N – 25).
• Ratings
  • Rated voltage: 32 V DC; rated current ≤ 30 A; breaking capacity 1 000 A.
• Dimensions & mechanical design
  • Detailed dimensional limits for Type N tabs and body; terminal strength tests require limited deformation (≤ 0.5 mm) and intact insulator after test.
• Marking and colour coding
  • Colour coding by rated current (e.g., 3 A - violet; 10 A - red; 30 A - green) to support identification in vehicle systems.
• Electrical performance & tests
  • Voltage drop measured across tabs with maximum mV limits by rating (e.g., 3 A: 200 mV; 5 A: 175 mV; 10 A: 140 mV; 20 A: 125 mV; 30 A: 120 mV).
  • Transient current cycling and steady‑state criteria to verify thermal/mechanical endurance under pulse loads.
  • Operating time‑rating matrix for multiples of rated current (examples: 1.1 × I - test duration 100 h; 1.35 × I - 0.75 s to 120 s; 3.5 × I - 0.04 s to 0.5 s).
  • Breaking capacity: must interrupt 1 000 A at 32 V DC for network time constants up to 2.5 ms; after tests leakage shall not exceed 0.5 mA at rated voltage.
• Mechanical tests
  • Terminal force tests (examples: axial and lateral loads) with specific forces applied and hold times.
• Test fixturing & cables
  • Test fixture connection resistance requirement (≤ 0.8 mΩ) and specified test cable cross‑sections for reproducible results (e.g., 3 A → 0.35 mm²; 5 A → 0.5 mm²; up to 30 A → 4.0 mm²).
• Visibility
  • Fuse‑links shall provide visible evidence of an open fuse‑element after operation.

Applications and users

Who benefits from ISO 8820-12:2020

• Automotive OEMs and wiring harness designers specifying fuses for 12–32 V vehicle electrical systems.
• Fuse and component manufacturers designing Type N blade fuses to meet automotive performance and dimensional standards.
• Test laboratories and quality engineers performing standardized electrical, thermal and mechanical validation.
• Suppliers and procurement teams ensuring interchangeability and regulatory compliance in vehicle assemblies.

Practical use

• Ensures reliable overcurrent protection in compact automotive circuits.
• Enables consistent selection, testing and interchangeability of sub‑miniature blade fuses across vehicle platforms.

Related standards

• ISO 8820‑1 - Definitions and general test requirements (referenced for procedures and terminology)
• ISO 8820‑2 - (other blade types/requirements as applicable)

Keywords: ISO 8820-12:2020, Type N sub‑miniature fuse, blade type fuses, automotive fuse standard, 32 V fuse-links, 1000 A breaking capacity, fuse test procedures, voltage drop, operating time-rating.