ELECTRIC SIGNS AND OUTLINE LIGHTING

70-635 Exception: Portable signs of the indoor type shall not be required to meet this requirement. (e) Minimum Thickness - Enclosure Metal. Sheet copper or aluminum shall be at least 0.020 inches (508 micrometers) thick. Sheet steel shall be of No. 28 MSG. Exception: For outline lighting and for electric-discharge signs, sheet steel shall be of No. 24 MSG if not ribbed, corrugated, or embossed over its entire surface and of No. 26 MSG if it is so ribbed, corrugated, or embossed. (f) Protection of Metal. All steel parts of enclosures shall be galvanized or otherwise protected from corrosion. (g) Enclosures Exposed to Weather. Enclosures for outdoor use shall be weatherproof and shall have at least two drain holes, each not larger than ½ inch (12.7 mm) or smaller than ¼ inch (6.35 mm). 600-9. Portable Signs or Sections. Portable signs or sections, letters, fixtures, symbols, and similar displays used in conjunction with fixed outdoor signs shall only be used where in compliance with all applicable provisions of this Code and, in addition, shall meet all of the following requirements: (a) Weatherproof Receptacle and Attachment Plug. A weatherproof receptacle and attachment plug having one pole for grounding shall be provided for each individual letter, fixture, or sign. (b) Cords. All cords shall be of the junior hard service or hard service types as designated in Table 400-4 and shall be 3-conductor with one conductor grounded as provided in Section 600-9(a). (c) Cord from Ground Level. No cord shall be less than 10 feet (3.05 m) from the ground level directly underneath. 600-10. Clearances. (a) Vertical and Horizontal. Signs and outline system enclosures shall have not less than the vertical and horizontal clearances from open conductors specified in Article 225. (b) Elevation. The bottom of sign and outline lighting enclosures shall not be less than 16 feet (4.88 m) above areas accessible to vehicles. Exception: The bottom of such enclosures shall be permitted to be less than 16 feet (4.88 m) above areas accessible to vehicles where such enclosures are protected from physical damage. 600-11. Outdoor Portable Signs. The wiring of an outdoor sign that is portable or mobile and is readily accessible shall be provided with factoryinstalled ground-fault circuit-interrupter protection for personnel. The ground-fault circuit-interrupter shall be an integral part of the attachment plug or shall be located in the power-supply cord within 12 inches (305 mm) of the attachment plug. Conductive supports of a sign specified in this section shall be considered part of the sign. 70-636 NATIONAL ELECTRICAL CODE B. 1000 Volts, Nominal, or Less 600-21. Installation of Conductors. (a) Wiring Method. Conductors shall be installed using any wiring method included in Chapter 3 suitable for the conditions that provides a means for equipment grounding, or in metal poles complying with all the requirements of Section 410-15(b). (b) Insulation and Size. Conductors shall be of a type listed for general use and shall not be smaller than No. 14. Exception No. 1: Conductors not smaller than No. 18 of a type listed in Table 402-3 shall be permitted: a. In portable signs. b. As short leads permanently attached to lampholders or electricdischarge ballasts. c. As leads not more than 8 feet (2.44 m) long permanently attached to electric-discharge lampholders or electric-discharge ballasts, if the leads are enclosed in wiring channels. d. For signs with multiple incandescent lamps requiring one conductor from a control to one or more lamps whose total load does not exceed 250 watts, if in an approved cable assembly of two or more conductors. Exception No. 2: Conductors not smaller than No. 20 shall be permitted as short leads permanently attached to synchronous motors. (c) Exposed to Weather. Conductors in raceways, metal-clad cable, or enclosures exposed to the weather shall be of a type listed for the conditions. Exception: This shall not apply where rigid metal conduit, intermediate metal conduit, rigid nonmetallic conduit, electrical metallic tubing, or enclosures are made raintight and arranged to drain. (d) Number of Conductors in Raceway. The number of conductors in a raceway for sign fixtures shall be in accordance with Table 1 of Chapter 9. (e) Conductors Soldered to Terminals. Where the conductors are fastened to lampholders other than of the pin type, they shall be soldered to the terminals or made with wire connectors, and the exposed parts of conductors and terminals shall be treated to prevent corrosion. Where the conductors are fastened to pin-type lampholders that protect the terminals from the entrance of water, and that have been found acceptable for sign use, the conductors shall be of the stranded type but shall not be required to be soldered to the terminals. 600-22. Lampholders. Lampholders shall be of the unswitched type having bodies of suitable insulating material and shall be so constructed and installed as to prevent turning. The screw-shell of all sign lampholders shall be connected to the grounded conductor of the circuit. Lampholders for outdoor signs shall be suitable for the application. 600-23. Conductors Within Signs and Troughs. Wires within the sign and outline lighting troughs shall be installed as to be mechanically secure. ARTICLE 600 - ELECTRIC SIGNS AND OUTLINE LIGHTING 70-637 600-24. Protection of Leads. Bushings shall be employed to protect wires feeding through enclosures. C. Over 1000 Volts, Nominal 600-31. Installation of Conductors. (a) Wiring Method. Conductors shall be installed as concealed conductors on insulators, in rigid metal conduit, in intermediate metal conduit, in rigid nonmetallic conduit, in flexible metal conduit, in liquidtight flexible metal conduit, or in electrical metallic tubing, or as Type MC cable. (FPN): See Section 600-5 for grounding requirements. Exception: Liquidtight flexible nonmetallic conduit shall be permitted where requirements for flexibility exist and where weather conditions require corrosion protection. (b) Insulation and Size. Conductors shall be of a type identified for voltage not less than the voltage of the circuit and shall not be smaller than No. 14. Exception: Conductors not smaller than No. 18 shall be permitted: a. As leads not more than 8 feet (2.44 m) long permanently attached to electric-discharge lampholders or electric-discharge ballasts, if the leads are enclosed in wiring channels. b. In show window displays or small portable signs, as leads not more than 8 feet (2.44 m) long that run from the line ends of the tubing to the secondary windings of transformers, if the leads are permanently attached within the transformer enclosure. (c) Bends in Conductors. Sharp bends in the conductors shall be avoided. (d) Concealed Conductors on Insulators - Indoors. Concealed conductors on insulators shall be separated from each other and from all objects other than the insulators on which they are mounted by a spacing of not less than 1½ inches (38 mm) for voltages above 10,000 and not less than 1 inch (25.4 mm) for voltages of 10,000 or less. They shall be installed in channels lined with noncombustible material and used for no other purpose, except that the primary circuit conductors shall be permitted to be in the same channel. The insulators shall be of noncombustible, nonabsorbent material. Concealed conductors on insulators shall not be allowed outside the sign enclosure. (e) Conductors in Raceways. Where conductors are covered with metal sheathing, the covering shall extend beyond the end of the raceway, terminates. and the surface of the cable shall not be damaged where the covering (1) In damp or wet locations, the insulation on all conductors shall extend beyond the metal covering or raceway not less than 4 inches (102 mm) for voltages over 10,000, 3 inches (76 mm) for voltages over 5000 but not exceeding 10,000, and 2 inches (50.8 mm) for voltages of 5000 or less. (2) In dry locations, the insulation shall extend beyond the end of the metal covering or raceways not less than 2½ inches (64 mm) for voltages 70-638 NATIONAL ELECTRICAL CODE over 10,000, 2 inches (50.8 mm) for voltages over 5000 but not exceeding 10,000, and 1½ inches (38 mm) for voltages of 5000 or less. (3) For conductors at grounded midpoint terminals, no spacing shall be required. (4) A metal raceway containing a single conductor from one secondary terminal of a transformer shall not exceed 20 feet (6.1 m) in length. (f) Show Windows and Similar Locations. Conductors that hang freely in the air, away from combustible material, and where not subject to physical damage, as in some show window displays, shall be required to be insulated for the voltage but not otherwise protected. (g) Between Tubing and Grounded Midpoint. Conductors shall be permitted to be run from the ends of tubing to the grounded midpoint of transformers specifically designed for the purpose and provided with terminals at the midpoint. Where such connections are made to the transformer grounded midpoint, the connections between the high-voltage terminals of the transformer and the line ends of the tubing shall be as short as possible. 600-32. Transformers. (a) Voltage. The transformer secondary open-circuit voltage shall not exceed 15,000 volts with an allowance on test of 1000 volts additional. For end-grounded transformers, the secondary open-circuit voltage shall not exceed 7500 volts with an allowance on test of 500 volts additional. (b) Type. Transformers shall be of a type identified for use with electrical-discharge tubing and shall be limited in rating to a maximum of 4500 volt-amperes. Open core-and-coil-type transformers shall be limited to 5000 volts with an allowance on test of 500 volts and to indoor applications in small portable signs. Transformers for outline lighting installations shall have secondary current ratings not more than 60 milliamperes. Exception: Where the transformers and all wiring connected to them are installed in accordance with Article 410 for electric-discharge lighting of the same voltage. (c) Exposed to Weather. Transformers used outdoors shall be of the weatherproof type or shall be protected from the weather by enclosure in the sign body or in a separate metal box. (d) Transformer Secondary Connections. The secondary windings of transformers shall not be connected in parallel or in series. Exception No. 1: Two transformers, each having one end of its secondary winding connected to the metal enclosure, shall be permitted to have their secondary windings connected in series to form the equivalent of a midpoint-grounded transformer. The grounded ends shall be connected by insulated conductors not smaller than No. 14. Exception No. 2: Transformers for small portable signs in show windows and similar locations, listed for the purpose, shall be permitted to be connected in series where they are equipped with secondary leads permanently attached to the secondary winding within the transformer enclosure. ARTICLE 600 - ELECTRIC SIGNS AND OUTLINE LIGHTING 70-639 The secondary leads shall not extend more than 8 feet (2.44 m) beyond the enclosure for attachment to the electrode ends of the tubing. The grounded ends shall be connected by insulated conductors not smaller than No. 18. (e) Accessibility. Transformers shall be located where accessible and shall be securely fastened in place. (f) Working Space. A work space at least 3 feet (914 mm) high and measuring at least 3 feet (914 mm) by 3 feet (914 mm) horizontally shall be provided about each transformer or its enclosure where not installed in a sign. (g) Attic Locations. Transformers shall be permitted to be located in attics, provided there is a passageway at least 3 feet (914 mm) in height and at least 2 feet (610 mm) in width, provided with a suitable, permanent, fixed walkway or catwalk at least 12 inches (305 mm) in width extending from the point of entry into the attic to each transformer. 600-33. Electric-Discharge Tubing. (a) Design. The tubing shall be of such length and design as not to cause a continuous overvoltage on the transformer. (b) Support. Tubing shall be adequately supported on noncombustible, adjustable. nonabsorbent supports. Tubing supports shall, where practicable, be (c) Contact with Flammable Material and Other Surfaces. The tubing shall be free from contact with flammable material and shall be located where not normally exposed to physical damage. Where operating at over 7500 volts, the tubing shall be supported on noncombustible, nonabsorbent insulating supports that maintain a spacing of not less than ¼ inch (6.35 mm) between the tubing and the nearest surface. Tubing. 600-34. Terminals and Electrode Receptacles for Electric-Discharge (a) Terminals. Terminals of the tubing shall be inaccessible to unqualified persons and isolated from combustible material and grounded metal or shall be enclosed. Where enclosed, they shall be separated from grounded metal and combustible material by noncombustible, nonabsorbent insulating material or by not less than 1½ inches (38 mm) of air. Terminals shall be relieved from stress by the independent support of the tubing. (b) Tube Connections Other than with Receptacles. Where tubes do not terminate in receptacles designed for the purpose, all energized parts of tube terminals and conductors shall be separated from grounded metal and combustible material by noncombustible, nonabsorbent insulating material or be supported so as to maintain a separation of not less than 1½ inches (38 mm) between conductors or between conductors and any grounded metal. Soldering or connection devices shall not be required for the connection of tube terminals to the conductors where they are spliced or joined so that they are mechanically and electrically secure. (c) Receptacles. Electrode receptacles for the tubing shall be of noncombustible, nonabsorbent insulating material. 70-640 NATIONAL ELECTRICAL CODE (d) Bushings. Where electrodes enter the enclosure of outdoor signs or of an indoor sign operating at a voltage in excess of 7500 volts, bushings shall be used unless receptacles are provided. Electrode terminal assemblies shall be supported not more than 6 inches (152 mm) from the electrode terminals. All electric-discharge tubing terminals shall be insulated with a material suitable for the voltages and environmental conditions expected during use. (e) Show Windows. In the exposed type of show-window signs, terminals shall be enclosed by receptacles. (f) Receptacles and Bushing Seals. A flexible, nonconducting seal shall be permitted to close the opening between the tubing and the receptacle or bushing against the entrance of dust or moisture. This seal shall not be in contact with grounded conductive material and shall not be depended upon for the insulation of the tubing. (g) Enclosures of Metal. Enclosures of metal for electrodes shall not be less than No. 24 MSG sheet metal. (h) Enclosures of Insulating Material. Enclosures of insulating material shall be noncombustible, nonabsorbent, and suitable for the voltage of the circuit. (i) Energized Parts. Energized parts shall be enclosed or suitably guarded to prevent contact. 600-35. Switches on Doors. Doors or covers giving access to uninsulated parts of indoor signs or outline lighting exceeding 600 volts, nominal, and accessible to unqualified persons shall either be provided with interlock switches that on the opening of the doors or covers disconnect the primary circuit, or shall be so fastened that the use of other than ordinary tools will be necessary to open them. 600-36. Fixed Outline Lighting and Skeleton-type Signs for Interior Use. (a) Tube Support. Gas tubing shall be supported independently of the conductors by means of insulators of noncombustible, nonabsorptive materials such as glass or porcelain or by suspension from suitable wires or chains. (b) Transformers. Transformers shall be installed in metal enclosures and as near as practicable to the gas tubing system. (c) Secondary Conductors. Secondary conductors shall be insulated for the voltage of the circuit and shall be enclosed in grounded metal raceway. Exception: Conductors not exceeding 4 feet (1.22 m) in length between gas tubing and adjacent metal enclosures shall be permitted to be enclosed in continuous glass or other insulating sleeves. 600-37. Portable Gas Tube Signs for Show Windows and Interior Use. This section shall apply to the installation and use of portable gas tube signs. (a) Location. Portable gas tube signs shall be for indoor use only.