What device is commonly used to measure the resistance of grounding systems?

The device commonly used to measure the resistance of grounding systems is an ohm meter. This instrument specifically measures electrical resistance in ohms, which is the standard unit for resistance. Grounding systems need to have specific resistance values to ensure safety and effectiveness; therefore, accurately measuring that resistance is crucial.

An ohm meter allows electricians and technicians to verify that grounding systems meet required specifications and perform as intended. Proper grounding is essential to prevent electrical shock hazards and ensure equipment works safely and efficiently.

Other instruments listed, like voltmeters and ammeters, serve different purposes. Voltmeters measure voltage, while ammeters measure current. A wattmeter measures power, which also does not provide resistance values. Each of these tools is integral to electrical work, but an ohm meter is specifically designed for resistance measurements, making it the correct choice in this context.