Which of the following statements about measuring voltage is incorrect?

Measuring voltage is a critical aspect of electrical engineering and safety. The statement regarding high voltages being measured safely without precautions is incorrect because high voltages pose significant risks to both the measuring equipment and the person conducting the measurement. Proper precautions are essential when working with high voltages to prevent electric shock, equipment damage, or even fatal accidents.

In contrast, the other statements accurately reflect principles of voltage measurement. Voltage should indeed always be measured in volts, as this is the standard unit of measure that quantifies electrical potential. Voltage is fundamentally a measure of electrical potential difference, representing the work done to move a unit charge between two points in an electric field. Additionally, line voltage being able to affect the functioning of electrical devices highlights the critical importance of understanding voltage levels in electrical systems, as improper voltage conditions can lead to malfunction or damage in devices.