Attach a ground wire from one of the threaded studs (A) at the bottom of the housing, to the mounting plate (B). The ground resistance between all system parts shall be <. 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. Grounding is necessary to assure correct operation of electrical devices, to assure safety. First, we review and compare medium-voltage distribution-system grounding methods. Next, we describe directional elements suitable to provide ground fault protection in solidly- and low-impedance grounded distribution systems. We then analyze the behavior of ungrounded systems under ground fault. Power from factory ground must be installed by a qualified electrician. Each DISTRIBUTION BOX and controller must be grounded. 26 mm 2 (10 AWG) ground wire must be used, and in all other markets a 6 mm 2 must be used. To verify the adequacy of a new grounding system.