Introduction to Glow-Wire Testing and IEC 60695 Compliance

The evaluation of fire hazard properties in electrical and electronic components is a critical aspect of product safety certification. The IEC 60695 series of standards, developed by the International Electrotechnical Commission (IEC), defines test methods for assessing the flammability of materials used in electrical equipment. Among these, the glow-wire test (IEC 60695-2-10, -2-11, -2-12, -2-13) simulates thermal stress caused by overheated or faulty components to determine material resistance to ignition and flame propagation.

The LISUN ZRS-3H Glow-Wire Test Apparatus is a precision instrument designed to conduct these assessments in compliance with IEC 60695, GB/T 5169, and other regional standards. It serves industries requiring stringent fire safety validation, including automotive electronics, household appliances, and aerospace components.

Principles of Glow-Wire Testing

The test involves heating a standardized Nichrome wire (typically 4 mm diameter) to a specified temperature (ranging from 550°C to 960°C) and applying it to the test specimen under controlled conditions. Key evaluation criteria include:

• Ignition Time: Duration before sustained flaming occurs.
• Flame Extinction Time: Time for flames to self-extinguish after removing the heat source.
• Material Dripping: Whether molten particles ignite a secondary substrate (e.g., tissue paper).

The LISUN ZRS-3H automates temperature regulation, force application, and timing measurements, ensuring repeatability and compliance with IEC 60695-2-10 (flammability) and -2-13 (ignitability).

Technical Specifications of the LISUN ZRS-3H

The apparatus incorporates a PID-controlled heating system, a digital anemometer for airflow verification, and a specimen holder compatible with diverse geometries (e.g., switch housings, PCB substrates).

Industry Applications and Case Studies

1. Household Appliances

Components such as power connectors, thermostat housings, and insulation materials must resist ignition from internal faults. The ZRS-3H verifies compliance with IEC 60335-1, mitigating fire risks in products like washing machines and microwaves.

2. Automotive Electronics

Underhood components (e.g., relays, fuse boxes) are subjected to thermal cycling. Testing at 850°C–960°C ensures materials meet ISO 20653 and LV 312-1 standards.

3. Medical Devices

Enclosures for diagnostic equipment undergo glow-wire testing to prevent combustion in oxygen-rich environments (per IEC 60601-1).

4. Aerospace and Aviation

Cabin electronics and wiring insulation are assessed under DO-160 Section 26, where flame propagation must be suppressed within 30 seconds.

Competitive Advantages of the LISUN ZRS-3H

• Precision Calibration: Integrated thermocouples and closed-loop temperature control minimize deviations (±2°C).
• Automated Data Logging: Real-time recording of ignition times, flame durations, and temperature profiles for audit trails.
• Modular Design: Interchangeable fixtures accommodate flat, curved, or irregular specimens.
• Safety Enhancements: Emergency cut-off, fume extraction compatibility, and insulated housings reduce operator hazards.

Testing Methodology and Validation

A typical test sequence involves:

1. Specimen Preparation: Conditioning at 23°C ± 2°C and 50% ± 5% RH for 48 hours.
2. Apparatus Setup: Calibrating the glow-wire temperature using a reference thermocouple.
3. Test Execution: Applying the heated wire for 30 ± 1 s while monitoring flame behavior.
4. Post-Test Analysis: Measuring burn lengths and assessing secondary ignition risks.

Data from the ZRS-3H is cross-referenced with IEC 60695 pass/fail criteria (e.g., no flames > 30 s, no ignition of tissue paper).

Regulatory and Standards Alignment

The ZRS-3H supports testing per:

• IEC 60695-2-10: Glow-wire apparatus and common test procedure.
• IEC 60695-2-11: Flammability end-product testing.
• UL 746A: Polymeric material evaluations.
• GB/T 5169.10–13: Chinese national standards.

FAQ Section

Q1: What distinguishes the ZRS-3H from manual glow-wire testers?
The ZRS-3H automates temperature stabilization, force application, and timing, reducing human error and improving reproducibility.

Q2: Can the apparatus test non-planar components?
Yes, adjustable specimen holders accommodate curved or irregular geometries, such as connector housings.

Q3: How frequently should the glow-wire element be replaced?
Per IEC 60695-2-10, the Nichrome wire must be replaced after 100 tests or if oxidation exceeds 5% diameter reduction.

Q4: Does the ZRS-3H support non-standard test durations?
Customizable timers allow deviations from the default 30 s exposure, useful for research applications.

Q5: Is fume extraction mandatory during testing?
While not compulsory, it is recommended for toxic material assessments (e.g., halogenated plastics).