IEC conductor and overcurrent protection sizing criteria?

[sjohns4]

I'm working with a volunteer organization to provide training to a group of engineers in Rwanda. Their primary focus is to provide drinking water, but as most of us water people have had to learn along the way you need electricity to turn the pump.

It's been well documented, and I observed first hand while there in 2013, many of the pump stations suffer from undersized conductors. I personally saw burnt wires still in service, and in talking to an operator through a translator, he told me he could only run the pump for short periods because the motor would heat up. I'm guessing that was primarily related to the ridiculously undersized and LONG service conductors between the primary transformer and station.

While I could teach the locals some basics using NEC criteria to keep them out of trouble, I'd rather use applicable standards even if they're not regularly followed anyway. Rwanda does subscribe to IEC codes and standards.

I suppose my first and big questions are:

Would you multiply the motor load by a factor to size conductors?

Motors are started using star-delta starters. How are over current protective devices sized in the IEC code for this method of starting? They did use thermal magnetic trip breakers.

Thanks for any input!

Mike

 

[7anoter4]

In my opinion, IEC 60364-5-52 it would be recommended.
IEC 60364 Part 5-52:Selection and erection of electrical equipment –Wiring systems. See also:
Sizing conductors and selecting protection devices - Legrand

http://www.legrand.com/files/fck/File/pdf/Power_guide/EX29008.pdf