ELECTRICAL SAFETY DESIGN

Wiring Design and Protection - Support, Enclosure, and Equipment Grounding

Proper grounding is important to prevent shock, stabilize voltage, and channel fault currents.

Metal enclosures for service equipment shall be grounded.

Metal cable trays, metal raceways, and metal enclosures for conductors shall be grounded, except for:

Metal enclosures such as sleeves that are used to protect cable assemblies from physical damage

Metal enclosures for conductors added to existing installations of open wire, knob-and-tube wiring, and non-metallic-sheathed cable which meet the following conditions:
- Runs are less than 25 feet
- Enclosures are free from probable contact with ground, grounded metal, metal laths, or other conductive materials
- Enclosures are guarded against employee contact.

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