600 Amperes 70mm2 x 4 OR 185mm2 x 2

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skhan855

Member
Location
Karachi, Pakistan
Hi
I am upgrading my system to bear load of 600 amperes,
Is it ok to do 70mm2 x 4 or 185mm2 x 2 would be better

Conditions:
Copper xlpe/pvc
Non armored
400 volts
temperature ambient 40C

Cable would be sandwich between two missionary wall filled with sand.

Commercially laying 70mm would cost me less than 185mm

Would support your help!!

Regards
Salman
 
petersonra

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
I think you would need to defer to whatever electrical standards are used in your location. In the US, the NEC does not recognize those wire sizes so they could not be used here.

i am also not sure you would be allowed to put it in a wall in sand here either.
 
Besoeker

Besoeker

Senior Member
Location
UK
petersonra said:
I think you would need to defer to whatever electrical standards are used in your location. In the US, the NEC does not recognize those wire sizes so they could not be used here.

i am also not sure you would be allowed to put it in a wall in sand here either.
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Given the voltage and cable sizes the standard used is probably BS7671 commonly known here as "The Regs".
I'm not sure about sand between the walls either - probably buried direct would be considered the installation method.
 
charlie b

charlie b

Moderator
Staff member
Location
Lockport, IL
Occupation
Semi-Retired Electrical Engineer
The question is essentially whether to use four sets of 1/0 or two sets of 300 KCMIL. But it is not a simple matter of converting wire sizes on the basis of cross-sectional area. In the US system, we have tables that tell us that the ampacity of a 1/0 is 150 amps, and that the ampacity of a 300 KCMIL is 285 amps. So four sets of 1/0 will give you 600 amps worth of wire, but two sets of 300 KCMIL will not. However, I am not aware of an ampacity table for metric sizes of conductors. So I can't say that either option will give you what you need.

Please note that our ampacity table assumes that the conductors are in conduit or other raceway, or direct buried in earth. The impact of putting the conductors between two walls and filling the space with sand is not addressed in our table.

Also please note that our ampacity table is based on having no more than three current-carrying conductors in the same conduit. If you use four sets of 1/0, and if all those wires are close to each other, then the tables would tell you that the 1/0 is no longer rated for 150 amps.
 
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