HV Machines - TinyModularThings/IC2Classic GitHub Wiki

HV Machines are machines that accept High Voltage (512 EU) or less power. When mined with a pickaxe they always drop an Advanced Machine Block, When wrenched they will have 75% chance to get the Machine back. If that fails then they will drop a Advanced Machine Block.

HV Machines can not Accept any Machine Upgrades at all.
But if they do support Inventory Upgrades then you can insert any of them.