BS EN 50525-2-21:2011 pdf free.Electric cables— Low voltageenergy cables of rated voltagesup to and including 450/750 V(Uo/U) Cables for general applications— Flexible cables with crosslinked elastomeric insulation.
BS EN 50525-2-21 The core assembly shall be covered with a sheath. The sheath shall be applied either in asingle layer, cross-linked elastomeric compound EM 2 to EN 50363-2-1, or in two layers， withthe inner layer made of one of the cross-linked elastomeric compounds EM 2 or EM 3 toEN 50363-2-1 and the outer layer of cross-linked elastomeric compound EM 2 toEN 50363-2-1.
The sheath in a single layer or the inner layer of the sheath in two layers shall fill the spacesbetween the cores.Where a tape of suitable material is applied around the core assembly(see NOTE 2 to 4.4.1.4) this requirement shall not apply,provided that the finished cablesshall not have any substantial cavity in the outer interstices between the cores.
The cable shall be marked with the CENELEC code HO7RN-F.The marking shall comply withClause 6 of EN 50525-1.Each cable shall comply with the appropriate requirements given in EN 50525-1,and theparticular requirements of this Part.Testing shall be in accordance with Table A.1, column 9.
NOTE For non-electrical tests on sheaths in two layers see EN 50525-1,5.7.2.3,c).
The dimensions of the cables shall conform to Table B.3 for the relevant size.The requirements to be met for the compatibility test shall be as given in Table C.1.The insulation shall be a cross-linked elastomeric compound,Type El 4 to EN 50363-1applied around each conductor.NOTE lt is permitted to apply a tape on each core.
Where the insulation is covered with a tape, it shall be non-hygroscopic and shall be appliedin such a manner that it can be removed without damage to the insulation.The cores of cables having two to five cores shall be twisted together.
The sheath applied in a single layer or the inner layer of the sheath in two layers shall, forcables with two to five cores，fill the spaces between the cores. Where a non-hygroscopictape of suitable material is applied around the core assembly (see NOTE 2 to 5.1.1.4) thisrequirement shall not apply,provided that the finished cables shall not have any substantialcavity in the outer interstices between the cores.BS EN 50525-2-21 pdf download.