How should impedance grounded systems be connected to the ground?

Impedance grounded systems are designed to limit the fault currents during a ground fault situation. The most effective way to connect these systems to the ground is through a grounding impedance device. This specific connection allows for controlled grounding, which limits the amount of fault current that can flow during a ground fault condition while providing a path for unbalanced currents.

Grounding impedance devices help in maintaining system stability and reducing equipment damage, thereby ensuring a safer operation. They are designed to control voltage rise on the grounded parts during a fault, which can protect both people and equipment.

The other choices do not serve to fulfill the specific function that a grounding impedance device provides in impedance grounded systems. For instance, while a grounding electrode is critical in many grounding scenarios, it doesn't include an impedance element to restrict fault current in the same way. Similarly, exothermic welding and concrete encased electrodes serve different functions in grounding and bonding applications that don't apply directly to impedance grounding needs.