Differences in the cross-sectional area of cable protection wires
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The specifications require the following cross-sectional areas for the cable shielding wires: the minimum cross-sectional area Sp (in mm2) of the shielding wire corresponds to the cross-sectional area of the phase wire as follows – S≤16: 16; 16<S≤35: 35; 35<S≤400: 400; 400<S≤800: …; S>800: …. According to these requirements, a 3*6+1*6 cable should meet the specifications better. However, in practice, the cross-sectional area of the shielding wire is usually one size smaller than that of the phase wire. As a result, 3*6+1*4 cables are more commonly used. What are the differences between 3*6+1*6 cables and 3*6+1*4 cables in terms of usage?
In the selection of conventional cables, the 3+1 configuration typically involves using 3 wires for the main circuit; the additional wire is used as a power supply when the voltage is 220V for the control circuit, or as a ground wire when connecting motors. The reason for having the same cross-sectional area for all 4 cores is that, in cases where most of the loads connected are 220V loads, it is possible that two phases have very low loads while another phase has a very high load; in such situations, the current in the neutral wire and that in this high-load phase can approach their maximum values. Therefore, in this case, the cross-sectional area of the neutral wire is required to be the same as that of the phase wires.
3*6+1*6: More secure, meets the requirements of new standards. 3*6+1*4: Cheaper, meets the requirements of old standards