Why can not I use aluminum for grounding?
Hello! Tell me, why can not I use an aluminum wire for grounding, if an aluminum conductor at a lower price has a higher conductivity? For example, SIP-4 for 16 squares conducts a current of 100 A, while 3 times more expensive copper wire for 4 squares conducts only 38 A, which is almost three times less than that of aluminum. So why is it better to use copper? Thank.
Hello! And who said that it is impossible? Are you interested in a wire for connecting from the shield to the ground electrode? There is such a requirement in PUE chapter 1.7.:
1.7.117. The grounding conductor connecting the earthing switch of the working (functional) grounding to the main grounding bus in electrical installations with voltage up to 1 kV must have a cross section of at least: copper - 10 mm2, aluminum - 16 mm2, steel - 75 mm2.
1.7.117. The grounding conductor connecting the earthing switch of the working (functional) grounding to the main grounding bus in electrical installations with voltage up to 1 kV must have a cross section of at least: copper - 10 mm2, aluminum - 16 mm2, steel - 75 mm2.
But the 119th paragraph prohibits the use of aluminum as a GZS, and this is due to the fact that aluminum is instantly oxidized in air. Since this is a protective conductor, after oxidation there can be no question of any protection.
In general, copper is used because it is harder, i.e. when clamped into a terminal block or under a bolt - it does not crush, and it does not oxidize like aluminum.
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