What is the function of a jumper bar in a grounding system?

In a grounding system, the function of a jumper bar is primarily to connect multiple grounds. This connection helps ensure a common reference point for electrical potential among different grounding points, which is crucial for safety and system stability. By using a jumper bar, different grounding systems can be bonded together, reducing the risk of ground loops and potential differences that might lead to equipment damage or safety hazards.

The other options do not accurately represent the role of a jumper bar. For instance, it does not serve as a power line, as that would imply it is carrying electrical current for operational purposes rather than for grounding. Similarly, a jumper bar is not used to disconnect lines or to amplify signals, as its objective is simply to provide a reliable and unified grounding connection.