Water Resistance Testing For Cables - The mechanical properties of sheath after water immersion

Water resistance testing is designed to determine whether a cable material is suitable for permanent submersion in water. It can also be referred to as a test to determine the mechanical properties of a cable sheath after water immersion. Conducted in accordance with the European standard BS EN 60811-501 requires a heated water bath and a tensile test machine in order to be able to undertake the test. 

The test methodology for water resistance testing describes that four sets of three samples, dumbell shaped, must be taken from the sheath of the chosen cable. They must be conditioned for a period of seven days at a temperature of (20 ±2)°C and at a relative humidity of (50 ± 5)%.

Once conditioned, one set is weighed and recorded to an accuracy of 0.1mg and immersed in potable water at (50 ± 2)°C for 100 days. After removal from the from the bath of potable water, surface water is removed and the samples conditioned for a further 16 hours at a temperature of (20 ± 5)°C and a relative humidity of (50 ± 5)%. The samples are then reweighed, and the weights again determined to the nearest 0.1mg.

The increase of mass after immersion shall not be greater than 40% of the mass of the sample prior to immersion.

The further three remaining sets of samples are then used to determine the tensile and elongation at break for the cable:

i) Without immersion

ii) After immersion in potable water at (50 ± 2)°C for 28 days

iii) After immersion in potable water at (50 ± 2)°C for 100 days

The tensile and elongation at break, and the variation between 28 days immersion and 100 days immersion, are calculated and the results must be greater than or equal to the values given in the below table.