HV Cables and LV Cable Laying

It is not unnecessary, it is just bad practice because of induced currents from uneven loads on the HV cables.

To avoid high voltage thrust on to an LV Cable insultaion during a HV Cable insulation failure, if they are laid together.

LT cable and HT cable temperature rise is totally different. If we lay the LT cables with HT cables the LT cables will get more heat from HT cables, it will create losses and Destroy the insulation of the LT cables.

Some times for cost implication we are selecting different type of Insulations.

Example- Paper/oil, Rubber, PVC, PE, XLPE and EPR. Every type of insulation having various temperature withstanding capacity.

In General practice

For LT cables we are choosing PVC insulation.

For HT cables we are choosing XLPE insulation.

These two insulation temperature withstanding capacity is totally different. XLPE will withstand more temperature than PVC. If we lay HT cables and LT cables in same tray. HT cables will produce more temperature than LT cables. It will affect the LT cables insulation by producing more heat.

And also More losses will occur.