Replied to the thread display of the maximum and minimum voltage for devices.PostPower Tier is exactly what Su5eD meant.
Tier 1: up to 32 EU/t
Tier 2: up to 128 EU/t
Tier 3: up to 512 EU/t
Tier 4: up to 2048 EU/t
Tier 5: (no machine has that): up to 8192 EU/t