Current ratings copper cables

Table 13.15 Current rating and technical data for 1100 V, single-core flexible, PVC insulated copper conductor cables for control and power wiring...

The above examples show that the resistance of an aluminium cable is some 60% greater than a copper conductor of the same length and cross-section. Therefore, if an aluminium cable is to replace a copper cable, the conductor size must be increased to carry the rated current as given by the tables in Appendix 4 of the lET Regulations and Appendix 6 of the On Site Guide. 

Magnetite Anodes of cast magnetite are now available. The anodes are produced as a hollow cylinder closed at one end (typically 60 mm diameter X 720 mm length). The method of cable connection is relatively difficult and requires the inner surface of the casting to be copper plated. At a current density of 75 Am consumption rates in seawater of less than 1 -5g/Ay are claimed. 

Due to its brittleness, the anode is cast as a hollow cylinder and closed at one end. The inner surface is then copper plated and the cylinder is filled with polystyrene. Epoxy resin is used to fill any remaining space. The anode cable is soldered to the copper plate. Magnetite anodes have been successfully used in the cathodic protection of buried structures and those immersed in seawater. The maximum operating current density is 0.12 kA m" and the anode consumption rate is approximately from 1 to 4 g A y. ... 

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