Repeated grounding wiring in the distribution box
Attach a ground wire from one of the threaded studs (A) at the bottom of the housing, to the mounting plate (B). • Good system grounding provides the path for normal load and fault currents while maintaining load and controls temporary overvoltage. This helps to reduce the potential difference that exists between conductive parts and the earth. Sometimes if I have a 3 or 4-gang plastic nail-on switch box that has a bunch of NM cables, when I'm making up the box rather than using a big blue wire-nut for my grounds I'll separate the grounds into 2 groups and use red/tan wirenuts instead, especially if there's 2 circuits in the box.
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