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 <. 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. Among these, IEC 60364 Earthing Requirements are the most widely adopted worldwide. IEC 60364 is a global benchmark for. Abstract: Discussed in this recommended practice is the system grounding of industrial and commercial power systems. It can also be an aid to all engineers responsible for the. The topic of system grounding is extremely important, as it affects the susceptibility of the system to voltage transients, determines the types of loads the system can accommodate, and helps to determine the system protection requirements.