overhead conductors used for 400/230 V circuits

[magoo2]

What size conductors would one use for the secondary mains on a 400/230 V system? The three-phase supply transformer is 315 kVA. The application is for a western African country.

 

[davidbeach]

What size do you calculate?

 

[magoo2]

I'd probably use something like 477 Al. This is my initial cut at it based on ultimate full load of 455 amps. I still have to look at the voltage profile and circuit lengths to see if that's OK.

What I meant to say was what are the standard metric sizes in mm-squared that are used in this area? Or could you point me to a conversion table from AWG to metric.

 

[davidbeach]

Look at table 8 in the back of the NEC, it gives mm² values for all the common AWG sizes. What might be available could be an entirely different matter.

 

[wareagle]

If you are sizing your equipment for 477 amps you would need a 600 amp service. The rating for 350 cu is 310 amps. A parallel service of 2 #350's = 620 amps. The rating for 500 kcm AL is 310 amps. Two per phase = 620 amps.

 

[wareagle]

I just realized you post was for Overhead Conductors. I found information at this site

http://www.cable.alcan.com/NR/rdonlyres/97F54474-BC52-4D63-8092-84CA52D610E9/0/multiplexoverhead.pdf

I think you may have some problems due to the weight of the cable.
2/0 4C 649 lbs/1000ft 210 amps
3/0 4C 801 lbs/1000ft 240 amps
4/0 4C 991 lbs/1000ft 280 amps
336 4C 1591 lbs/1000ft 330 amps

If your load is 455 amps, you would require 2 - 3/0 cables.
What is the estimated distance for the installation?