The samples of the insulation or sheath material are prepared in small strips to a mass of 50 ± 5 mg. The samples are then placed in a glass tube with a strip of litmus indicator paper, and the tube is then placed in thermostatic equipment at the specified temperature.

The time that elapses for the litmus paper to change from pH 5 to a value between pH 2 and pH 3 is measured, which is in the colour variation to red. If the colour of the paper does not change, the test continues for the duration established in the specific cable standard.

The test is considered to have a satisfactory outcome if the mean value of the thermal stability times is not less than the value specified in the specific cable standard.

La entrada Thermal stability test for PVC insulations and sheaths. UNE-EN 60811-405 se publicó primero en CEISLAB.

Loss of mass test on insulation

The samples obtained from the insulated conductors or from the insulation, are previously subjected to stabilisation at ambient temperature inside a dryer to obtain the first mass measurement, M₁. Afterwards, heat treatment in an oven is applied for the time and at the temperature established in the specific product standard. Finally, the samples are once again stabilised at ambient temperature in the dryer for the established period of time before taking the second mass measurement, M₂.

Assessment of the results is based on the difference between the masses obtained before and after treatment. The test results are considered to be satisfactory if the obtained value is lower than the requirements established in the specific product standard.

Loss of mass test on sheaths.

The samples are prepared by removing all the external elements from the sheath without damaging it, and are stabilised in the dryer to obtain the first mass measurement, M₁. Afterwards, the samples are subjected to heat treatment in an oven for the time and at the temperature established in the product standard. Finally, the samples are dried again for the required time and to return to ambient temperature before the second measurement of the mass is taken, M₂.

The difference between the masses before and after treatment must be less than the requirements defined in the specific product standard for the test result to be considered satisfactory.

La entrada Loss of mass test on thermoplastic insulation and sheaths. UNE-EN 60811-409 se publicó primero en CEISLAB.

Water absorption tests permit assessing the performance of cables when submerged in water for prolonged periods of time.

Water absorption electrical test UNE-EN 60811-402

During this test, insulated conductor samples are submerged in a receptacle with water for a set time at a set temperature according to the specific product standard. During this period, the samples are subjected to direct current voltage in accordance with the insulation thickness.

The test is considered to be successful if no perforations of the insulated conductors occur.

Water absorption gravimetric method UNE-EN 60811-402

Depending on the type of cable, the test samples can either be complete cable samples for cables with conductors of a nominal thickness equal to or less than 25 mm², and nominal voltage rating equal to or less than 0.6/1kV. Or smooth, parallel strips for all other cable types.

When testing complete cables, the initial mass of the sample is measured after drying, M₁, to ensure a constant mass. The samples are then placed in a “U” shape over a variable sized mandrel depending on the diameter of the sample, in a receptacle with water, without submerging the ends.

The sample must remain submerged in the receptacle for the set period of time and at the temperature according to the specific product standard. The assembly is then allowed to cool down to ambient temperature, and after the surface is dried, the sample is weighed again, M₂.

Finally, the sample is dried using the same method as used prior to submerging it, and it is weighed for a third time M₃.

The test is considered to be successful when the variation in mass is less than the amount established in the specific product standard.

In the case of samples in the form of strips, after prior drying, the initial mass is measured, M₁. The sample is then submerged in water for a set time at a set temperature according to the specific product standard . After this period, and drying the surface, the sample is weighed again, M₂.

Finally, the sample is subjected to the same drying process as prior to submerging it in water to measure the mass for a third time, M₃.

The test result is considered to be satisfactory when the variation in mass is less than the amount established in the specific product standard.

La entrada WATER ABSORPTION TESTS UNE-EN 60811-402 se publicó primero en CEISLAB.