POWER CABLE SELECTION

Full guidance may be obtained from a current edition of the Wiring Regulations, as maintained by the Institution of Electrical Engineers.

Hi PWslack,

If I calculate that for a motor of say 100kW, 415V, 3 ph, that I get 204A ( that is 100000/(415x1.732x0.8x 0.85)), how do I decide whether to use a 3 core cable or single core cable of 3 runs. Appreciate if you can advise.

I get confused about the 3 core cable current - current rating in catalog for 3 core is it for one core out of the three ?

I deduce that 3c and 1c say of 120mm2 will have conductor size (copper cross section area only) of 120mm2. So if a single core cable is rated to carry more than 204A - I cannot use it. Am I right? because I have 3 terminals to terminate.

I am really confused. Appreciate your help.

May I add to Mr Slack's advice...

Depends what country you're in and what code applies to you for your understanding, inasmuchas - all North America (and some South) generally use AWG, while the rest of the world uses metric cross-sectional area (csa), and the different explainations of insulating materials, their uses, and how they are utilised. So if you use the NEC (US), CEC (Canada), IEE Regs (UK), or the Aus/NZ Wiring Rules you've pretty much covered the world.