Attach a ground wire from one of the threaded studs (A) at the bottom of the housing, to the mounting plate (B). The ground resistance between all system parts shall be <. The correct connection method of Distribution box grounding wire mainly includes the following steps: 1. Preparation: First, you need to prepare some necessary tools, including grounding wire, grounding rod, voltmeter, insulating gloves and insulating tools. Covers wiring, placement, standards, and expert tips for a compliant setup. **Test the grounding resistance**: Use a. Power from factory ground must be installed by a qualified electrician. Each DISTRIBUTION BOX and controller must be grounded. A grounding pigtail is a short, isolated length of green-insulated or bare copper wire used to create a splice, linking the circuit's incoming ground wire to both the metal box and the.