How are the metal shielding of power cables made up?
The cover and clearance of the metal shield shall be in accordance with the following requirements:The resistance of copper wire in metal screen shall be in line with the national standard when applicable. The nominal sectional area of copper wire shield shall be determined according to the capacity of the fault current.Soft copper wire copper wire shielded by a layer of overlapping Rao package composition, the surface of the copper or copper reverse package tied rao. The average gap between adjacent copper wires shall be no more than 4mmThe copper tape shielding shall be composed of a soft copper strip covered with overlapping strips, or double copper strip space wrapping. The covering ratio between the copper strips shall be 15% of the copper strip width (nominal value), and the minimum cover ratio shall be no less than 5%.
The metal shield can also be a metal sleeve or a metal armoured layer meeting the requirement.When choosing metal shielding materials, the possibility of corrosion should not be considered, not only for mechanical safety, but also for electrical safety.
The metal shield shall be composed of one or more metal bands, metal structures, concentric layers of metal wires or a combination of metal wires and metal strips.
