Grounding of the units: 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. Power from factory ground must be installed by a qualified electrician. Each DISTRIBUTION BOX and controller must be grounded. Define when a 3 pole vs 4 pole transfer switch should be used so that neutral. Abstract: System grounding considerations affect many aspects of an electrical system. The voltage, system arrangement, loads connected, and continuity of. 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. A correct understanding of the basic principles involved will help him/her to avoid mistakes in grounding system design.