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. If its grounding fails, every connected device becomes vulnerable. And those cable shielding layers? They're like armored vests for your data and. Metal electrical boxes must be grounded because they are conductive components that enclose energized wires and connections.