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. Grounding of the units: Attach a ground wire from one of. • Good system grounding provides the path for normal load and fault currents while maintaining load and controls temporary overvoltage. Good equipment grounding ensures personnel safety. Most North American distribution systems have a neutral that acts as a return conductor and as an equipment. 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 helps to reduce the potential difference that exists between conductive parts and the earth. Equipment Protection: Grounding protects substation. A sub panel is a secondary distribution point that receives power from the main service panel, allowing for the extension of electrical service to a remote area of a building or a separate structure like a garage or shed.