26 mm 2 (10 AWG) ground wire must be used, and in all other markets a 6 mm 2 must be used. Each DISTRIBUTION BOX and controller must be grounded. Grounding of the units: Attach a ground wire from one of. However, when it comes to choosing the best location for a power distribution box, there are several factors to consider. Whether in a home or an industrial facility, this box keeps your electrical setup organized, functional, and efficient. 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. Check the safety of the installation location Away from moisture and corrosive environment The installation location should be away from moisture sources and corrosive. The grounding system provides a low-impedance path for fault current and limits the voltage rise on the normally non-current-carrying metallic components of the electrical distribution system. During fault conditions, low impedance results in high fault current flow, causing overcurrent protective.