Medium Voltage (MV) cable laying requires strict engineering compliance to prevent insulation punctures and thermal issues. Under QCS 2014, several guidelines govern the installation of 11kV, 22kV, and 33kV systems.
Before pulling, ducts must be proved using a calibration mandrel sized at 80% to 90% of the duct diameter. This ensures the pipe has not collapsed and is free of rocks and debris. Cable lube must be applied generously to reduce pulling friction.
MV cables have rigid bending profiles. The minimum bending radius for multi-core armored cables is typically 12 to 15 times the outer cable diameter. Exceeding this bend limits damages the insulation screen, leading to partial discharge failures later.
Open trenches require a 150mm thick bed of clean, sieved sand below and above the cable. A protective layer of concrete tiles or cable warning tape must be installed before backfilling, clearly identifying the utility line below.