26 mm 2 (10 AWG) ground wire must be used, and in all other markets a 6 mm 2 must be used. Power from factory ground must be installed by a qualified electrician. Grounding of the units: Attach a ground wire from one of. The correct connection method of Distribution box grounding wire mainly includes the following steps: 1. This position is the connection point of the grounding wire in the. When done, that will leave me needing to tie six (12-gauge) ground wires together: One to each load, one to each switch, one to the ground screw on the box itself, and one coming in from the subpanel. That's an awkward number to attempt to connect with a wire nut. Whether you're an electrician or a DIY enthusiast, this guide will help you understand the basics of home electrical distribution.