IEC 60502-1-2021 pdf free.Power cables with extruded insulation and their accessories for rated voltages from1kV(Um=1,2kV)upto30kV(Um=36kV)- Part 1: Cables for rated voltages of1 kV (Um= 1,2 kV) and 3 kV (Um= 3,6 kV).
The metal layers of the individual cores shall be in contact with each other.
Cables with an additional collective metal layer (see Clause 8) of the same material as the underlying individual metal layers shall have an inner covering over the laid-up cores. The inner covering and fillers shall comply with 7.2 and shall be non-hygroscopic.
When the underlying individual metal layers and the collective metal layer are of different materials, they shall be separated by an extruded sheath of one of the materials specified in 13.2. For lead-sheathed cables, the separation from the underlying individual metal layers may be obtained by an inner covering in accordance with 7.2.
For cables having neither armour, nor concentric conductor, nor other collective metal layer (see Clause 8), the inner covering may be omitted, provided the outer shape of the cable remains practically circular. The oversheath may penetrate into the interstices of the cores, except in the case of thermoplastic oversheaths over circular cores exceeding 10 mm2. If. however, an inner covering is applied, its thickness need not comply with 7.2.3 nor 7.2.4.
8 Metal layers for single-core and multicore cables
The following types of metal layers are included in this document:
a) metal screen (see Clause 9);
b) concentric conductor (see Clause 10):
C) lead sheath (see Clause 11);
d) metal armour (see Clause 12).
The metal layer(s) shall comprise one or more of the types listed above and shall be non- magnetic when applied to either single-core cables or individual cores of multicore cables.
9 Metal screen
9.1 Construction
The metal screen shall consist of one or more tapes, or a braid, or a concentric layer of wires or a combination of wires and tape(s).
It may also be a sheath or, in the case of a collective screen, an armour which complies with 9.2.
When choosing the material of the screen, special consideration shall be given to the possibility of corrosion, not only for mechanical safety but also for electrical safety.IEC 60502-1 pdf download.