Large machines undergoing a resistance insulation testing using a megohmmeter should be discharged to remove any accumulated electrostatic/capacitive charge stored. When should this discharge be performed?

Correct Answer: Option A — prior to and after conducting the insulation resistance check

Large rotating machinery exhibits significant capacitance, storing hazardous electrostatic charges during DC megger application. Per IEEE 45 guidelines, windings must be safely discharged to ground both before testing to eliminate residual voltage and after testing to protect personnel and sensitive insulation.