Factor to account for imperfect thermal contact between conductor or screen, sheath or armour and surrounding or adjacent non-metallic materials.
Screen wires are considered isolated if the wires cover <70% of the circumference. Isolated screen wires are considered fully embedded if they are separated by at east one wire diameter and fully surrounded by non-metallic materials, then a value of 0.7 can be used, otherwise 0.5.
|1.0||for conductor and screen of oil-filled cables|
|0.9||if completely bonded on one side|
|0.5||for isolated screen wires, not fuly embedded|