The metal box of the distribution box, the electrical installation board, and the metal base and casing of the electrical appliances in the box must be grounded. The protective neutral wire should be reliably connected through the terminal board. Each DISTRIBUTION BOX and controller must be grounded. Grounding of the units: Attach a ground wire from one of. NEC 250. 148 doesn't play favorites: The code mandates that all metallic parts of electrical boxes must bond to ground—no exceptions for cabinet doors. Which NEC rules apply to electrical. We can see the box is mounted to the drywall with simple sheet metal mounting tabs, and based on the hack with the two supply conductors, we can be almost certain that box isn't actually grounded. If a fault occurs, such as a hot wire touching the metal enclosure, the box instantly becomes energized, creating a severe shock hazard.
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