IEC 60287-2-1 Ed. 2.0 b PDF

Electric cables – Calculation of the current rating – Part 2-1: Thermal resistance – Calculation of the thermal resistance

IEC 60287-2-1 Ed. 2.0 b – Electric cables – Calculation of the current rating – Part 2-1: Thermal resistance – Calculation of the thermal resistance

IEC 60287-2-1:2015 is solely 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,in troughs or in steel pipes, bothwith and without partial drying-out of the soil, as well as cables in air. The term “steady state” is intended to mean acontinuous constantcurrent (100 %load factor) just sufficientto produce asymptotically the maximumconductor temperature, the surrounding ambient conditions being assumed constant. This part of IEC 60287 provides formulae forthermal resistance. This second edition of IEC60287-2-1 cancelsand replaces the first edition,published in1994,Amendment 1:2001, Amendment 2:2006 and Corrigendum 1:2008. This edition includes the following significant technical changes with respect tothe previous edition:
a) inclusion of a reference to the use of finite element methods where analytical methods are not available for the calculation of external thermal resistance;
b) explanation about SL and SA type cables;
c) calculation method for T3 for unarmoured three-core cables with extruded insulation and individual copper tape screens on each core;
d) change of condition for X in 5.4;
e) inclusion of constants or installation conditions for water filled ducts in Table 4.