Part 404 of IEC 60811 specifies a mineral oil immersion test method that is commonly used to assess the oil resistance of cross-linked compounds used as cable sheathing materials. The purpose of this test is to determine whether the material can be classified as oil resistant.

IEC 60811-404 specifies the following main steps and requirements:

1.Pre-treatment: The sheathing material compound needs to be immersed for at least 16 hours after extrusion or any cross-linking treatment. This means that the test material needs to be tested after a specific treatment to simulate actual conditions of use.

2.Specimen Preparation: Five specimens are prepared according to the procedures of BS EN/IEC 60811-501. These specimens will be used for testing.

3.Oil Immersion: The specimens are immersed in mineral oil (usually No. 2 oil, such as IRM 902 as defined in ISO 1817) preheated to the specified test temperature. The specimen needs to be kept in the oil for the specified time.

4.De-oiling in oil: At the end of the test, the specimen is removed from the oil and gently blotted to remove excess oil. The specimen is then suspended at ambient temperature for at least 16 hours but not more than 24 hours to ensure that it is thoroughly dry.

5.Tensile and elongation measurements: Tensile and elongation measurements were carried out on the test pieces in accordance with BS EN/IEC 60811-501. Five specimens immersed in oil were compared with untreated control specimens to calculate the percentage difference in performance.

The final assessment is based on the percentage difference in performance between the oil-impregnated specimens and the untreated specimens, which should not exceed the limits specified in the standard for the particular cable type. This test helps to determine whether the cable sheathing material is sufficiently resistant to oil to ensure that the cable is not affected by oil during use.