Lead Sheathed Cables/ Current Ratings/Installation Conditions


Installation Conditions


Installation Conditions
1. Continuous operating temperature of conductor  
               a) PVC type-5 insulated 85° C
               b) XLPE insulated 90° C
2. Ambient temperature 52° C
3. Temperature of ground 35° C
4. Depth of laying in ground  
               a) LV Cables 750 mm
               b) MV Cables 1000 mm
5. Thermal resistivity of soil 1.2° C .m/W
 
OTHER CONDITIONS
A. LOW VOLTAGE CABLES 600/1000V
1. SINGLE CORE CABLES
     i) Two cables spaced one cable diameter installed vertical in air.
     ii) Two cables spaced one cable diameter laid horizontally underground.
2. MULTI CORE CABLES
     i) Single cable touching wall installed in air.
     ii) Single isolated buried cable in ground.
     iii) Single cable installed in single isolated buried ducts -
               a) Duct Material Earthen Ware
               b) Depth of laying i) LV Cables : 750 mm
ii) MV Cables : 1000 mm
               c) Duct diameter
                      i) Cable dia. up to 65 mm OD = 130mm & ID = 100 mm
                      ii) Cable dia. above 65 mm OD = 160 mm & ID = 125mm
 
B. MEDIUM VOLTAGE CABLES 6.6 KV TO 33 KV
1. SINGLE CORE CABLES
      i) Three Cables, trefoil, in air, two point bonding, separated from wall.
      ii) Three Cables flat with a gap of one cable diameter installed vertically in air, separated from wall. Single point or cross blonded.
      iii) Three Cables with gap one cable diamenter laid horizontally underground
2. MULTI CORE CABLES
     i) Single cable touching wall installed in air.  
     ii) Single isolated buried cable in ground.