Special precautions must be taken with electrical wiring in the above types of buildings because of dust from feed and litter and corrosive agents associated with animal confinement. Buildings constructed under the "Agricultural Exempt" building status (no building permit required) that are used for the above purposes must also comply with the following requirements. Milking parlors and areas where livestock may come in contact with metallic equipment have additional requirements including Equipotential Planes and require electrical plan review prior to construction.
- Barns, Riding Arenas and buildings which provide animal habitat, animal care or feed storage are subject to National Electrical Code Article 547 – Agricultural Buildings. Wiring methods, equipment and light fixtures must be of an approved type for the environment where they are installed. Areas requiring special attention are those where excessive dust and dust with water may accumulate, damp or wet locations and corrosive atmospheres. Generally, this requires a wiring method which is suitable for damp or wet locations. All wiring subject to physical damage shall be protected. Nonmetallic sheathed cable (Romex) is not an approved wiring method for animal habitat, animal care or feed storage areas. NEC 547.5
- Electrical distribution panels should be located in tack room or other area away from animal habitat and feed storage to protect overcurrent devices from dust and moisture or will require a NEMA 3R rated enclosure suitable for wet locations. NEC 547.6
- Separate equipment grounding conductor required. Non-current carrying metal parts of equipment, raceways and other enclosures must be grounded by a copper equipment grounding conductor to equipment. If installed underground, the equipment grounding conductor shall be insulated or covered. NEC 547.5(F)
- In areas separated from animals and feed storage, Nonmetallic sheath cable (Romex) can be used where not subject to physical damage. Exposed nonmetallic sheathed cable shall be protected where it is installed horizontally below 8 feet above the floor. Exposed nonmetallic sheath cable below 8 feet above the floor that enters the top and bottom of a panelboard shall be protected from physical damage by conduit, ½ inch plywood or ½ inch drywall, per Oregon Electrical Specialty Code amendment to NEC 334.15(B).
- Luminaires (lighting fixtures) shall be installed to minimize the entrance of dust, foreign matter, moisture and corrosive material. Generally, luminaires of this type are those suitable for damp or wet locations. Luminaires exposed to physical damage shall be protected by suitable guards. NEC 547.8
- Wiring, luminaires and equipment in a wash area must be approved for wet location. NEC 547.8
- All 120 volt, 15 and 20 amp receptacle outlets installed for personnel require GFCI protection except commercial installations. NEC 210.8(A)(2).