The primary function of this screw is to bond the metal enclosure of an electrical box or device to the equipment grounding conductor (the bare or green wire). Power from factory ground must be installed by a qualified electrician. Each DISTRIBUTION BOX and controller must be grounded. When an electrical fault occurs, such as a hot wire touching the metal box, the screw provides a direct, low-impedance route for that stray. Bonding is the connecting together of metal parts of chassis, assemblies, frames, shields, and enclosures to reduce the effects of emi and ground noise. Today, electrical systems are essential for homes and industries.
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