What is the Glow Wire Test and how is it performed?

The Glow Wire Test (Hot Wire Test) is a flammability test carried out to determine the heat resistance of plastics and insulating materials used in electrical and electronic devices against high currents. This test is especially critical for fire safety, as it measures the ignition, burning duration, and self-extinguishing capability of materials. The reaction of the material to fire is observed when a heated metal wire comes into contact with the test specimen.

In electrical devices, overheating caused by short circuits or high current flow can ignite materials. The Glow Wire Test determines under standardized conditions whether the material can withstand such risks.

Principle of the Glow Wire Test

The test is generally performed according to IEC 60695 and EN 60695 standards. The principle is as follows:

Test Equipment and Wire

  • A 4 mm diameter nichrome wire is heated to specific temperatures (550°C, 650°C, 750°C, 850°C, or 960°C).

Specimen Preparation

  • The plastic or insulating specimen is prepared to simulate its real application.

Contact Duration

  • The heated wire is applied to the specimen for 30 seconds.

Observation and Recording

  • The ignition time, burning duration, and whether molten particles ignite the underlying tissue or paper are recorded.

Applicable Standards and Scope

The Glow Wire Test is carried out according to the following national and international standards:

  • EN 60695 / IEC 60695
    Defines general methodologies and safety requirements for fire hazard testing of electrical equipment.

  • IEC 60529
    Specifies IP protection codes for enclosures, indirectly related to fire testing.

  • EN 60332-1-1 / 1-2 / 1-3
    Defines vertical flame propagation resistance tests for cables.

  • EN 61386-1
    Specifies flame resistance tests for conduit systems used in electrical installations.

These standards ensure that test results from different manufacturers are comparable and reliable.

Evaluation of Test Results

The criteria for passing the Glow Wire Test are:

  • Ignition duration must not exceed 30 seconds.

  • The specimen must self-extinguish after the test.

  • Molten particles must not ignite the underlying paper or tissue.

If these conditions are met, the specimen is considered to have “passed the test.”

Industrial Applications of the Glow Wire Test

The Glow Wire Test is a mandatory safety test in many industries:

  • Household Electrical Appliances

    • Sockets, plugs, switches, coffee machines, irons

  • Automotive Industry

    • Interior plastic parts, headlamp housings, fuse boxes

  • Electronic Devices

    • Computer housings, televisions, power adapters

  • Cables and Conduit Systems

    • Electrical cables, cable ducts, installation conduits

Advantages and Limitations of the Glow Wire Test

Advantages:

  • Based on internationally recognized standards.

  • Provides test conditions close to real-life applications.

  • Helps minimize fire hazards.

Limitations:

  • Does not cover all fire scenarios, only specific temperatures and contact times.

  • Material behavior may vary depending on shape and size.

Conclusion

The Glow Wire Test is a critical method for evaluating the fire safety of electrical and electronic products. Conducted according to standards such as EN 60695 and IEC 60695, this test is essential for ensuring that products are safe for the market. It also plays an important role in international certification processes.

Frequently Asked Questions (FAQ)

1. At what temperatures is the Glow Wire Test performed?
It is usually conducted between 550°C and 960°C, depending on the standard requirements.

2. What are the criteria for passing the test?
Ignition time must not exceed 30 seconds, the material must self-extinguish, and molten particles must not cause ignition.

3. Which standards govern the Glow Wire Test?
The main standards are EN 60695, IEC 60695, IEC 60529, EN 60332 series, and EN 61386-1.

4. Is the Glow Wire Test mandatory?
Yes, it is mandatory in many countries for CE certification of electrical and electronic products.

5. Does the specimen get damaged during the test?
Yes, the material undergoes thermal and mechanical stress, leading to physical deformation.