Hi, I am struggling to answer the question 13 in quiz 14 for Current Carrying Capacity.
3 Phase.
4mm multicore, copper, PVC.
installed flat on wall.
touching another cable.
ambient temp of room does not rise above 25 degrees.
derating for bunched cables is - 0.85. T.22
derating for ambient temp -1.21 T.27(1)
0.85 x 1.21 = 1.02
CCC of 4mm - 29A
CCC after derating - 1.02 x 29 = 29.84, I am confused because I assumed the 25 degrees uprated cable if anyone can tell how I am doing this wrong would be greatly appreciated.
thanks, Jai.