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Hi All.

I am installing a new sub mains cable on a project in the uk, can someone advise me on the correct way to calculate the maximum current carrying capacity of a 95mm 4core swa xlpe lsf in a 65meter run, 10meters buried under ground and 55m on cable tray?
If i calculate it using 65 metres on tray the maximum capacity is alot more than if i calculate it as 65 meters under ground.. is there a way to use part of both correction factors?
 

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You always must use the lower ampacity of the cable. In the NEC we do have a section that allows us some leeway if the run of cable in the lower ampacity is less than 10' and no more than 10% of the entire run.

If the underground emerges into a splice you can use larger cable for the underground and the smaller cable for the cable tray run.

I realize that you are from the UK but I bet it is similar
 
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