6 DESIGN RECOMMENDATIONS AND FEATURES6.1 GeneralAll cables shall be single core with fire retardant halogen free outer sheath.6.2 ConductorsFor all cables, conductors shall be class 2 for fixed installations and class 5 for flexible installations.Cable conductors shall be of high conductivity either annealed copper or aluminium, stranded type.Power cables shall incorporate a conductor screen made of an extruded semi-conducting compound applied to the conductors and in combination with earth screen of copper tape.6.3 InsulationThe insulation shall be made of extruded material (XLPE), in accordance with IEC 60840. EPR insulated cables may be quoted as an alternative option, subject to Client approval. Insulation shall be heat and moisture resistant and flame retardant.Power cables shall incorporate an insulation screen which consists of an extruded semiconducting layer in combination with a metallic layer (copper tape).6.4 Metallic shieldPower cables shall be equipped with a cable shield, which shall be sized to carry on the fault current corresponding to a maximum fault level of 1 kA, 1s.Cable shields shall be earthed only at one point, the opposite side shall be left open. The Supplier shall also verify the induced voltage on the screen both for rated short time current and exceptional short circuit current, as per Table 2.If the inducted voltage on the shield shall exceed the withstand capability of the cable, the Supplier shall design and include in the scope a dedicated surge arrester (including a box and all necessary accessories).6.5 Cable TerminalThe supply also includes suitable cable terminal fitting cable features, required design parameter and ambient condition.Terminal creepage distance shall be in accordance with paragraph 3.3.Cable terminal shall preferably be in polymeric material, in order to minimize the risk of damages in case of explosion.6.6 InstallationAll cables shall be installed inside cable ways. Cable terminations will be placed indoor.In case cable links are composed by several cables in parallel per phase, cable’s terminals of the same phase shall be electrically and mechanically connected, in order to adequately share currents and bending stresses on terminals.Cables inside cable ways shall be fixed by bolted cleats and spacers; the installed cables shouldn’t be too rigid; cables shall be able to move a little (inside defined bounds) to dissipate short-circuit mechanical energy. Wherever a cable has to make a curve, suitable accessories shall be used to achieve a quasi-rigid system (e.g. a hollow stainless steel double tube, one to contain the cable, the other to provide mechanical properties).The supplier is responsible to design and supply the cable fitting system, considering installation type, cable mechanical features and electrodynamical forces deriving from