The samples are prepared by removing the external coatings that may be applied over the insulation or sheath.

These samples are then wound around a mandrel in line with the cable dimensions, and then subjected to heat treatment in an oven in accordance with the specific product standard. After the set period, the samples are allowed to cool at room temperature without removing them from the mandrel, and satisfactorily pass the test if there is no visible cracking.

La entrada Resistance of insulations and sheaths to cracking (heat shock test) UNE-EN 60811-509 se publicó primero en CEISLAB.

This test is carried out by hanging club or tubular shaped samples in an oven, to which a traction force is applied through weights secured by grips to the lower part.

The test result assesses the minimum lengthening capacity of the sample in this state of tension for the set time and at the set temperature established in the specific standard.

La entrada Hot set test UNE-EN 60811-507 se publicó primero en CEISLAB.

The test consists of determining the force necessary to separate the metallic screen from the outer sheath of the cable.

To do this, the sheath is secured to one of the traction equipment grips and the aluminium tape, folded over itself at 180º is secured to the other grip. This means that when traction is applied, a separating force between both items is produced until breakage.

The test is considered to have a favourable result if the force to apply exceeds the requirements in the specific product standard.

La entrada Strippability between the outer sheath and metallic screen. UNE-HD 605 se publicó primero en CEISLAB.

Through the use of traction equipment in compression mode, pressure is applied to the cable through a needle connected to a low voltage circuit in order to determine the force required for the needle to penetrate the insulation or sheath and to make contact with the conductor.

The test is considered to be satisfactory if the force applied to penetrate the cable is higher than the minimum required for the cable.

La entrada Dynamic penetration se publicó primero en CEISLAB.

The complete cable sample is secured vertically in the test equipment so that the upper part is subjected to alternating bending in both directions to an angle of 90º on both sides of the vertical plane and the lower part is secured with a weight.

The test is considered to be satisfactory if the sample meets the requirements established in the specific cable standard, usually defined as a number of bending cycles.

La entrada BENDING se publicó primero en CEISLAB.

The complete cable sample is fitted vertically to the test equipment and the upper part is subjected to cyclic bending according to the radius of the sample and the lower part is secured with a weight.

The test is considered to be satisfactory if the sample meets the requirements established in the specific cable standard.

La entrada Cyclic bending test se publicó primero en CEISLAB.

Test methods

Shrinkage tests for insulation. UNE-EN 60811-502

The samples are prepared by separating all the coatings from the insulated conductors. These samples are tested horizontally in an air oven at the temperature and for the duration established in the specific product standard, while being supported by the bare conductors or a layer of talcum powder, although in all cases this permits free movement of the insulation when heat is applied.

Once the samples have cooled to ambient temperature after heat treatment, the difference in length measured before heating, L₁ and after heating L₂ is recorded. The test is satisfactory if shrinkage of the insulation is less than established in the specific product standard.

Shrinkage tests for sheaths. UNE-EN 60811-503

The test is carried out on a complete cable sample, applying periodical heat cycles at the temperature and duration established in the specific product standard.

At the end of the heat treatment, shrinkage is measured before, L₁, and after treatment, L₂. The performance of the samples is considered to be satisfactory if shrinkage is less than established in the specific product standard.

La entrada SHRINKAGE se publicó primero en CEISLAB.

The objective of this test is to verify that no softening of the material takes place when subjected to temperature and pressure, simulating operating conditions which the samples could be exposed to through the heat from the current and mechanical stresses applied by the installation.

The test is carried out using a device consisting of a blade placed on the sample and by means of a counterweight, it applies constant pressure over a period of time during which the sample is heated in accordance with the standard for the specific product.

As a result of this test, the mark made by pressure on the sample must not be greater than defined for the material type.

La entrada Pressure tests at high temperature. UNE-EN 60811-508 se publicó primero en CEISLAB.

This test allows determining the resistance of sheath materials to oil when subjected to thermal ageing by immersion of samples in oil for a set time at a set temperature as per the specific standard for the cable

Once thermal ageing has been performed, and after cleaning any oil remains from the samples and returning them to room temperature, they are subjected to mechanical properties tests to determine the integrity of the samples.

La entrada Mineral oil immersion tests for sheaths.UNE-EN 60811-404 se publicó primero en CEISLAB.

Accelerated ageing tests allow us to study the performance of materials cables are made of in a short period of time by simulating how these materials would perform over a long period of time.

Ageing in an air oven. UNE-EN 60811-401

Ageing in this case is carried out in a hot air oven with natural or forced air circulation.

The samples, dumbbell or tubular type, are placed in the centre of the oven, keeping it at the set temperature for the time established in the specific standard for the cable.

At the end of the accelerated ageing process, and after allowing the samples to return to room temperature, they are subjected to the determination of mechanical properties test to check the effects of the process on the sample.

Ageing in an air bomb. UNE-EN 60811-412

Ageing is carried out in an air chamber in which the pressure is increased to reach 0.55 MPa for a set time at a set temperature as per the standard for the specific cable (Link to cable types).

After completing the ageing process and allowing the sample to return to room temperature, it is subjected to the determination of mechanical properties test. to assess the condition of the materials.

La entrada Thermal ageing methods se publicó primero en CEISLAB.