2.1. Conductive part.
2.1.1. Electrical features
The conductor's role is to conduct current, it must have a resistivity (ρ) very low to limit (for neglected) losses by Joules effect:
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The cross section depends on the current in the conductor. The cross section standards are from 0.6 to 360 mm2 (J is the density of current in A/mm2
2.1.2. Mechanical feature
The conductor should be enough flexible to follow the complicated path of the conduits. There are:
Multi strand conductors are made with several twisted strands. The strands are put in several layers.
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The single strand conductor has one strand and the cross section can be up to 35 mm².
The flexibility of a cable depends of the number of strand for the same conductive cross section. The flexibility is defined in 6 classes. Class 1: less flexible, class 6 more flexible. We usually use classes 1, 2, 5, 6.
Standards
Cables for fixed installations: Classes 1 and 2
The flexibles: Classes 5 and 6
Copper welding cables: Class 6
