Which instrument is utilized to check resistance on a pre-installed ground stud?

The instrument utilized to check resistance on a pre-installed ground stud is the ohmmeter. An ohmmeter is specifically designed to measure electrical resistance, typically in ohms. When checking a ground stud, it’s crucial to determine if there is a low-resistance path to ground, ensuring that any potential faults or surges in electrical systems are properly grounded.

While a voltmeter measures voltage and an ammeter measures current, neither is suited for checking resistance directly. A multimeter can measure resistance but includes additional functions, such as measuring voltage and current. However, the primary tool for exclusively assessing resistance is the ohmmeter. Therefore, in the context of the question, using an ohmmeter is the most appropriate choice for measuring resistance specifically on a ground stud.