Underground MV Feeders

[AAEB]

Which are more advantageous, single MV conductor via single RNC or 3 MV cables + ground via single conduit RNC? Both installed underground and encased in concrete.

thanks

 

[AAEB]

to be more specific, it is a 13.8kv system, the owner wants us to intall this 3-#4/0, EPR cables + 100mm2 bare copper wire via single 6inches RNC encased in concrete to save space, less conduits and flux cancellation which is reasonable. but we are proposing to install these MV Cables in a 4-4inches RNC ductbank, 1-EPR cable per conduit and bare copper in a separate conduit. Our purpose is when 1 phase fails, we can still use the other 2 phases unlike in a triangular configuration, in where it might damage the other phases in the event of faults anf short circuits. Flux are not an issue since we are using a Rigid Non-metallic Conduit.

what do you thinks guys?

thanks

 

[BJ Conner]

Why.

Why.

The way the owner wants it will be less reactance between phases ( greater distance between conductors) and less reactance to ground. Ground is close to conductors). EPR cable ( ssuming it not damaged during installation ) is very reliable. They way they want it is cheaper as well.

 

[mkgrady]

I'd put them all in one conduit and run a spare conduit.