IEC 60811-3-2:1985 pdf free download.Common test methods for insulating and sheathing materials of electric cables – Part 3: Methods specific to PVC compounds – Section Two: Loss of mass test – Thermal stability test.
1 Scope
Replace the first paragraph of this clause by the following:
IEC 60811-3-2:1985 specifies the test methods to be used for testing polymeric insulating and sheathing materials of electric and optical cables for power distribution and telecommunications, including cables used in ships and in offshore applications.
9. Thermal stability test for Insulations and sheaths
9.1 Test equipment
a) Glass tubes closed at one end (e.g. by melting), 110 mm long with an outer diameter of approximately 5 mm and an inner diameter of 4.0 ± 0.5 mm.
b) Universal indicating paper with a pH range of 1 to 10.
c) Thermostatically controlled heating apparatus for a temperature specified in the standard for the type of cable, or, if the temperature is not specified in the cable standard, at
200 ± 0.5 °C.
d) Thermometer calibrated in divisions of 0.1 °C.
e) Stop-watch or a suitable time meter.
9.2 Test procedure
a) From the insulation of each core to be tested or from the sheath to be tested, three samples, each of 50 ± 5 mg, shall be taken in the form of a strip, if possible. For small thicknesses the sample may consist of two or more strips. Each sample shall be inserted into a glass tube as specified in Item a) of Sub-clause 9.1. The sample shall occupy the bottom of the tube and not project more than 30 mm above the bottom.
b) A strip of dry universal indicating paper, as specified in Item b) of Sub-clause 9.1, about 15 mm long and 3 mm wide, shall be inserted into the open end (top) of the glass tube so that the strip protrudes about 5 mm out of the tube and can be bent to keep it in position.
c) The glass tube shall be placed into the heating apparatus, as specified in Item c) of Sub-clause 9.1, which has already attained the test temperature specified. The glass tube shall be inserted into the heating apparatus to a depth of 60 mm.
d) The time taken for the universal indicating paper to change colour from a pH value of 5 to a pH value of 3 shall be measured, or the test continued for the specified duration without the colour change occurring. The colour change point shall be considered to have been reached when the red colouring of the universal indicating paper characteristic of a pH value of 3 is just becoming visible. The universal indicating paper shall be renewed (especially for long duration stabilities) towards the end of the expected test time every 5 to 10 mm, so that the change point is better visible.IEC 60811-3-2:1985 pdf download.