Electric cables – Calculation of the current rating – Part 3-3: Sections on operating conditions – Cables crossing external heat sources
|Publication Date:||1 May 2007|
|ICS Code (Cables):||29.060.20|
This section of IEC 60287-3 is applicable to the conditions of steady-state operation of cables at all alternating voltages, and direct voltages up to 5 kV, buried directly in the ground, in ducts, troughs or in steel pipes, both with and without partial drying-out of the soil, as well as cables in air. The term "steady state" is intended to mean a continuous constant current (100 % load factor) just sufficient to produce asymptotically the maximum conductor temperature, the surrounding ambient conditions being assumed constant.
This section concerns reference operating conditions and selection of cable type.