In a subpanel, only the grounding conductor is permitted to connect back to the the grounding terminal bar in the main panel. 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. 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. This ensures that when an energized conductor touches the enclosure, the consequential fault current gets low-impedance path to securely conduct to ground.
