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. 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. In an. For commercial and industrial systems, the types of power sources generally fall into four broad categories: Utility Service: The system grounding is usually determined by the secondary winding configuration of the upstream utility substation transformer. In fact, a lot of myths have been built around this subject, although it is quite a simple one when approached. Let's cut through the technical jargon for a second. When lightning strikes or a rogue voltage surge decides to crash the party, proper grounding steps in like a.