26 mm 2 (10 AWG) ground wire must be used, and in all other markets a 6 mm 2 must be used. Secondary equipment grounding refers to connecting the secondary equipment (such as relay protection and computer monitoring systems) in power plants and substations to the earth via dedicated conductors. We then analyze the behavior of ungrounded systems under ground fault conditions and introduce a new ground directional element for these systems. Then we. Grounding is a mechanism to protect distribution equipment and people under normal operating conditions, abnormal operational (overcurrent and overvoltage) responses, and hazardous conditions such as shocks. Whether you're a seasoned pro or just starting out, this comprehensive guide will give you practical.