During a test on a fire pump with an electric driver, which instrument would the inspector use to measure electrical parameters?

• A. Calibrator
• B. Multimeter
• C. Refractor
• D. Tachometer

Answer: (B)

The key idea here is to verify electrical conditions you’ll encounter when testing an electric-drive fire pump. You need an instrument that can read electrical values like voltage, current, and resistance, as well as check continuity. A multimeter is built for this purpose: it can measure AC voltage from the power supply, DC voltage in control circuits, resistance of windings, and the continuity of wiring. It gives a practical, on-site way to confirm the driver and motor circuit are within spec and wired correctly.

A calibrator is used to set or verify the accuracy of other instruments, not to measure live electrical parameters in a system under test. A refractor is an optical instrument used to bend light, not for electrical work. A tachometer measures rotational speed, which isn’t what you need when checking electrical characteristics of the drive.