Coal Mine Rescue Field Test 2 Taken from the 2018 Tennessee Mine Rescue Contest held in Cove Lake, TN Progress Indicator: Question 2 of 10 2.  Medium Voltage is defined as: Choices: Voltage from 600 to 1,000 volts Voltage from 661 to 1,000 volts Voltage from 551 to 1,000 volts Voltage from 676 to 1,000 volts