Cable Core Choosing

British Standard 7671.

Try cable manufactures ratings tables.

based on application, we can use 3 core,3.5 core and 4 core. 1 )For 3 phase motor: 3 core cable we can use. additional we have to connect 2wires for earthing. 2)3.5 core cables generally we can use incoming supply to the panel boards. Where lighting load is less/ Neutral where we are using control supply. 3) 4 core cables for balanced loads. where neutral required with earthing.

thanks for your reply rybrk...