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: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. The neutral conductor is typically the grounded conductor connected to the system's neutral point, carrying current under normal operation. It establishes a dedicated, low-resistance return path for stray electrical current, preventing dangerous voltage from building up on conductive surfaces. Code Change Summary: Clarifications were made regarding the connection of equipment grounding conductors in a box.