400a Supply

[epsngr]

I am planning on installing a 400A supply from a 500KVA transformer substation. The design is for a 4 x 1c 240mm cable, about 120m length. What is the best way to install these cables? single duct for all cables - is this possible. Trefoil will require 3 cables but I have 4 cables. Open escavation, do I need to seperate the cables.

 

I have checked that if the cables are grouped, derated current will be 319A. My max demand is 250A/phase.

 

I need some advise from your experiences.

[AB2005]

Dear

 

This is the best to lay the cables separately as there heat and flux not de-rate the other cables but this will increase your expenditures. If your maximum demand is 250A only and there is no fair for increment of load in future, then you may lay the cables as grouped.

 

[epsngr]

Dear

 

This is the best to lay the cables separately as there heat and flux not de-rate the other cables but this will increase your expenditures. If your maximum demand is 250A only and there is no fair for increment of load in future, then you may lay the cables as grouped.

 

 

Thanks, I will install the cables in group in view of the fact that the demand is below and derating will still give me enough capacity.