154 RULES AND REQUIREMENTS OF THE NATIONAL BOARD OF FIRE UNDERWRITERS FOR NATIONAL ELECTRIC ASSOCIATION. EDITION OF JAN. 1, 1895. The use of wire ways for rendering concealed wiring permanently accessible, is most heartily endorsed and recommended; and this method of accessible concealed construction is advised for general use. Architects are urged, when drawing plans and specifications, to make provision for the channeling and pocketing of buildings for electric light or power wires, and in specifications for electric gas lighting to require a two-wire circuit, whether the building is to be wired for electric lighting or not, so that no part of the gas fixtures or gas piping be allowed to be used for the gas lighting circuit. CENTRAL STATIONS. Class A. FOR LIGHT OR POWER. These Rules also apply to Dynamo Rooms in Isolated Plants, connected with or detached from buildings used for other purposes; also to all varieties of apparatus therein of both high and low potential. 1. GENERATORS: a. Must be located in a dry place. b. Must be insulated on floors or base-frames, which must be kept filled, to prevent absorption of moisture, and also kept clean and dry. c. Must never be placed in a room where any hazardous process is carried on, more in places where they would be exposed to inflammable gases, or flyings, or combustible material. d. Must each be provided with a waterproof covering. 2. CARE AND ATTENDANCE: A competent man must be kept on duty in the room where generators are operating. Oily waste must be kept in approved metal cans, and removed daily. (See Definitions). 3. CONDUCTORS: From generators, switchboards, rheostats, or other instruments, and thence to outside lines, conductors a. Must be in plain sight, and readily accessible. b. Must be wholly on non-combustible insulators, such as glass or porcelain. c. Must be separated from contact with floors, partitions or walls, through which they may pass, by non-combustible insulating tubes, such as glass or porcelain. d. Must be kept rigidly so far apart that they cannot come in contact. e. Must be covered with non-inflammable insulating material sufficient to prevent accidental contact, except that "bus bars bus bars" may be made of bare metal. f. Must have ample carrying capacity, to prevent heating. (See Capacity of Wires Table.) 4. SWITCHBOARDS: a. Must be so placed as to reduce to a minimum the danger of communicating fire to adjacent combustible material. (See Definitions). b. Must be accessible from all sides when the connections are on the back; or may be placed against a brick or stone wall when the wiring is entirely on the face. c. Must be kept free from moisture. d. Must be made of non-combustible material, or of hard wood in skeleton form, filled to prevent absorption of moisture. e. Bus bars must be equipped in accordance with Rule 3 for placing conductors. 5. RESISTANCE BOXES AND EQUALIZERS: a. Must be equipped with metal, or other non-combustible frames. (See Definitions). b. Must be placed on the switchboard, or, if not thereon, at a distance of a foot from combustible material, or separated therefrom by a non-inflammable, non-absorptive, insulating material. 6. LIGHTNING ARRESTERS: a. Must be attached to each side of every overhead circuit connected with the station. b. Must be mounted on non-combustible bases in plain sight on the switchboard, or in an equally accessible place, away from combustible material. 66 c. Must be connected with at least two earths" by separate wires, not smaller than No. 6 B. & S., which must not be connected to any pipe within the building, and must be run as nearly as possible in a straight line from the arresters to the earth connection. d. Must be so constructed as not to maintain an arc after the discharge has passed. 7. TESTING: a. All series and alternating circuits |