REQUIREMENTS FOR ELECTRICAL INSTALLATIONS 70-25

110-18. Arcing Parts. Parts of electric equipment which in ordinary operation produce arcs, sparks, flames, or molten metal shall be enclosed or separated and isolated from all combustible material. (FPN): For hazardous (classified) locations, see Articles 500 through 517. For motors, see Section 430-14. 110-19. Light and Power from Railway Conductors. Circuits for lighting and power shall not be connected to any system containing trolley wires with a ground return. Exception: Car houses, power houses, or passenger and freight stations operated in connection with electric railways. 110-21. Marking. The manufacturer's name, trademark, or other descriptive marking by which the organization responsible for the product may be identified shall be placed on all electric equipment. Other markings shall be provided indicating voltage, current, wattage, or other ratings as are specified elsewhere in this Code. The marking shall be of sufficient durability to withstand the environment involved. 110-22. Identification of Disconnecting Means. Each disconnecting means required by this Code for motors and appliances, and each service, feeder, or branch circuit at the point where it originates, shall be legibly marked to indicate its purpose unless located and arranged so the purpose is evident. The marking shall be of sufficient durability to withstand the environment involved. Where circuit breakers or fuses are applied in compliance with the series combination ratings marked on the equipment by the manufacturer, the equipment enclosure(s) shall be legibly marked in the field to indicate the equipment has been applied with a series combination rating. The marking shall be readily visible and state "Caution - Series Rated System A Available. Identified Replacement Component Required." (FPN): See Section 240-83(c) for interrupting rating marking for end-use equipment. B. Over 600 Volts, Nominal 110-30. General. Conductors and equipment used on circuits over 600 volts, nominal, shall comply with all applicable provisions of the preceding sections of this article and with the following sections, which supplement or modify the preceding sections. In no case shall the provisions of this part apply to equipment on the supply side of the service conductors. 110-31. Enclosure for Electrical Installations. Electrical installations in a vault, room, or closet or in an area surrounded by a wall, screen, or fence, access to which is controlled by lock and key or other approved means, shall be considered to be accessible to qualified persons only. The type of enclosure used in a given case shall be designed and constructed according to the nature and degree of the hazard(s) associated with the installation. A wall, screen, or fence shall be used to enclose an outdoor electrical installation to deter access by persons who are not qualified. A fence shall not be less than 7 feet (2.13 m) in height. 70-26 NATIONAL ELECTRICAL CODE (FPN No. 1): Article 450 covers minimum construction requirements for transformer vaults. (FPN No. 2): Isolation by elevation is covered in paragraph (b) of this section and in Section 110-34. (FPN No. 3): A fence made of a combination of 6 feet (1.80 m) or more of fence fabric and a 1-foot (300-mm) or more extension utilizing three or more strands of barbed wire is equivalent to a 7-foot (2.13-m) fence. (a) Indoor Installations. (1) In Places Accessible to Unqualified Persons. Indoor electrical installations that are open to unqualified persons shall be made with metalenclosed equipment or shall be enclosed in a vault or in an area access to which is controlled by a lock. Metal-enclosed switchgear, unit substations, transformers, pull boxes, connection boxes, and other similar associated equipment shall be marked with appropriate caution signs. Openings in ventilated dry-type transformers or similar openings in other equipment shall be designed so that foreign objects inserted through these openings will be deflected from energized parts. (2) In Places Accessible to Qualified Persons Only. Indoor electrical installations considered accessible to qualified persons only in accordance with this section shall comply with Sections 110-34, 710-32, and 710-33. (b) Outdoor Installations. (1) In Places Accessible to Unqualified Persons. Outdoor electrical installations that are open to unqualified persons shall comply with Article 225. (FPN): For clearances of conductors for system voltages over 600 volts, nominal, see National Electrical Safety Code, ANSI C2-1990. (2) In Places Accessible to Qualified Persons Only. Outdoor electrical installations having exposed live parts shall be accessible to qualified persons only in accordance with the first paragraph of this section and shall comply with Sections 110-34, 710-32, and 710-33. (c) Metal-Enclosed Equipment Accessible to Unqualified Persons. Ventilating or similar openings in equipment shall be so designed that foreign objects inserted through these openings will be deflected from energized parts. Where exposed to physical damage from vehicular traffic, suitable guards shall be provided. Metal-enclosed equipment located outdoors and accessible to the general public shall be designed so that exposed nuts or bolts cannot be readily removed, permitting access to live parts. Where metal-enclosed equipment is accessible to the general public and the bottom of the enclosure is less than 8 feet (2.44 m) above the floor or grade level, the enclosure door or hinged cover shall be kept locked. 110-32. Work Space about Equipment. Sufficient space shall be provided and maintained about electric equipment to permit ready and safe operation and maintenance of such equipment. Where energized parts are exposed, the minimum clear work space shall not be less than 6½ feet (1.98 m) high (measured vertically from the floor or platform), or less than 3 feet (914 mm) wide (measured parallel to the equipment). The depth shall