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 < 0. Attach a second grounding wire from the mounting. The correct connection method of Distribution box grounding wire mainly includes the following steps: 1. In the box are a GFCI, a regular 15-amp 2-outlet receptacle, an incoming 14/2 from the switch (about ten feet away), two outgoing 14/2 (one to each "branch" of switched outlets), and a green grounding.