Cable size check please

[Oliver Townsend]

Hi we are quoting for installing the main feed for a public swimming pool , its a 3 phase install with 3 no. 300 AMP main fuses . we will be installing a 315 3pn switched fused isolator then SWA on cable tray at a distance of 25 mtrs to the main board , i have allowed for 240 mm2 cable with 70 mm earth am i right or can i install smaller ???

 

[westward10]

Assuming it is XLPE it is plenty big enough. Can you install smaller, I would say yes. You not done any calcs then.

 

[timbobelfast]

Hi we are quoting for installing the main feed for a public swimming pool , its a 3 phase install with 3 no. 300 AMP main fuses . we will be installing a 315 3pn switched fused isolator then SWA on cable tray at a distance of 25 mtrs to the main board , i have allowed for 240 mm2 cable with 70 mm earth am i right or can i install smaller ???

Need more info!

What's your design current, ambient temp and any other factors?!

 

[Risteard]

Assuming it is XLPE

Unless you have switchgear etc. with terminals suitable for 90 degree operation then it being cross-linked polyethelene isn't terribly relevant.