Personal Protective Equipment and Self-Contained Breathing Apparatus No. 3 Questions taken from Jones & Bartlett Fundamentals of Fire Fighter Skills (3rd Edition) Progress Indicator: Question 2 of 22 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