Cable Sizing Calculation and Design

Example Question

Step 1 and 2 : Information detail and formula

Step 3 : Refer table insulation type

Step 3 : Check the Derating factor for variation in ambient temperature, K1

Step 4 : Refer table tray/cable

Step 4 : Check the Derating factor for adjacent circuits, K2

Step 5 : Compute the rating current

Step 6 : Check the cable sizing based on the table

Step 1 : Determine the minimum cable size based on voltage drop, SB

Step 2 : Determine the mV/A/m based on the table

Step 4 : Calculate ∆𝑉𝐷𝑟𝑜𝑝

Step 5: Determine the resistance coefficient, R and X based on the table

Step 6 : Determine the minimum cable size based on voltage drop, SB.

Step 6 : Determine ∆𝑉𝑑𝑟𝑜𝑝% .

Step 1: Calculate size of cable during 𝐼𝑠𝑐.

Step 2 : Check the k value from the table

Step 3 : Calculate size of cable during 𝐼𝑠𝑐.

Step 1 : Calculate the actual size of cable.