IEC 60332-1/BS 4066-1 (Flame Test On Single Vertical Insulated Wires/Cables)

This test details a method of test for the assessment of the flame propagation characteristics of a single wire or You are not allowed to view links. Register or Login this test, a 60cm cable sample is fixed vertically inside a metallic box and a 175mm long flame is applied at 45℃ froma gas burner placed at 450mm from the top at the upper portion. The specimen is deemed to have passed this test, if afterburning has ceased, the charred or affected position does not reach within 50mm of the lower edge of the top clamp which
is equivalent to 425mm above the point of flame application. The test method is not suitable for the testing of some smallwires due to the melting of the conductors during the time of application of the flame.

Understanding the IEC 60332-1 / BS 4066-1 Flame Test for Single Insulated Cables

The IEC 60332-1 (also known as BS 4066-1) is an international standard that outlines a test method for evaluating the flame propagation characteristics of a single insulated wire or cable. This test is critical in assessing fire safety compliance for cables used in residential, industrial, and commercial installations.

Purpose of the Test

The main objective of the IEC 60332-1 test is to assess a cable's ability to resist vertical flame propagation when exposed to a small ignition source. In other words, the test evaluates whether a single wire or cable will self-extinguish after exposure to flame and prevent the fire from traveling upward along the cable. This helps reduce the spread of fire in confined spaces such as cable ducts, panels, or equipment enclosures.

Test Setup

The test is conducted under controlled conditions in a laboratory environment using the following setup:

• A 60 cm long cable sample is fixed vertically inside a metallic enclosure.
• A 175 mm long test flame is applied to the sample at a 45° angle.
• The flame source is a gas burner placed 450 mm from the top of the cable.
• The ambient test temperature is maintained at 45°C.

Pass Criteria

The cable is considered to have passed the test if:

• After the flame is removed, the burning stops (self-extinguishes).
• The charred or damaged portion of the cable does not reach within 50 mm of the lower edge of the top clamp, which is equivalent to 425 mm above the flame application point.

Limitations

It is important to note that this test is not suitable for very small wires or conductors. Thin wires may melt during flame exposure, leading to inconsistent or invalid results. Therefore, alternative test methods may be needed for such cases.

Conclusion

IEC 60332-1 / BS 4066-1 is a fundamental flame test for single cables, offering a basic measure of fire resistance. While it doesn't cover full fire performance (like smoke density or toxic gas emission), it is a reliable benchmark to ensure that individual cables do not contribute to flame spread in the event of a fire.