I have 2no parallel 4-core 400mm2 XLPE SWA cables laid in pvc ducts directly in the ground. They run some 90m with a load which ranges between 780A to 1230A, the latter becoming more common for longer periods due to the addition of recently installed plant. I am not sure of the cable manufacturer, nor indeed if they are XLPE as the glands are made into the bottom of the switchboards. The installing sparks must have been super nimble contortionists! Anyway, I am seeking an approximate current carrying capacity for the method of installation. I believe the cables are under sized although not showing any signs of undue degradation. The Flir shows them around 100C at one end.
Thanks Mike. Table 4E4A doesnt have a column for cables in the ground but reference to the 70C cousin in 4D4A shows a fairly dramatic difference between the clipped direct rating of a 300mm2 cable and its direct in the ground rating, the latter carrying only 67% of the clipped direct rating. Applying a similar rating to the 90C cable would put the ccc of a 400 at around 450A.
Thanks Mike. Table 4E4A doesnt have a column for cables in the ground but reference to the 70C cousin in 4D4A shows a fairly dramatic difference between the clipped direct rating of a 300mm2 cable and its direct in the ground rating, the latter carrying only 67% of the clipped direct rating. Applying a similar rating to the 90C cable would put the ccc of a 400 at around 450A.
