HV cables are the highest tier conventional cables. They can tolerate High Voltage (512 EU/t) and Extreme Voltage (2048 EU/t), but have an extremely high distance-related energy loss. HV cables can have 3 different levels of insulation. Considering that a shock from a poorly insulated HV cable will most likely prove fatal, it is recommended to insulate them well unless the cable is located in a completely unreachable area. Even then, insulation should be applied to reduce the massive energy losses.
Although in-game it currently lists "4xInsulated", that is incorrect as you are adding a layer of insulation each time, not doubling the insulation each time. It is actually "3xIns" and should get renamed eventually in some future patch.
|Cable type||EU/b||Energy loss|
|HV Uninsulated||1||1 EU every block|
|HV Insulated||0.95||1 EU every 1.05 blocks|
|HV 2x Insulated||0.9||1 EU every 1.11 blocks|
|HV 3x Insulated||0.8||1 EU every 1.25 blocks|