26 mm 2 (10 AWG) ground wire must be used, and in all other markets a 6 mm 2 must be used. Power from factory ground must be installed by a qualified electrician. Grounding of the units: Attach a ground wire from one of. Today, we're diving deep into the world of distribution box grounding, breaking down the standards, and shining a light on those sneaky mistakes that even experienced electricians sometimes make. This position is the connection point of the grounding wire in the. Metal electrical boxes must be grounded because they are conductive components that enclose energized wires and connections. If a fault occurs, such as a hot wire touching the metal enclosure, the box instantly becomes energized, creating a severe shock hazard. Make sure all tools are intact to prevent accidents during the grounding.