Grounding of the units: 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. 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. Utility Service: The system grounding is usually determined by the secondary winding configuration of the upstream utility substation transformer. Power from factory ground must be installed by a qualified electrician. Each DISTRIBUTION BOX and controller must be grounded. While these guidelines apply to the majority of.