ELECTRICALLY DRIVEN IRRIGATION MACHINES 70-691

675-2. Definitions. Center Pivot Irrigation Machines: A center pivot irrigation machine is a multimotored irrigation machine that revolves around a central pivot and employs alignment switches or similar devices to control individual motors. Collector Rings: A collector ring is an assembly of slip rings for transferring electrical energy from a stationary to a rotating member. Irrigation Machines: An irrigation machine is an electrically driven or controlled machine, with one or more motors, not hand portable, and used primarily to transport and distribute water for agricultural purposes. 675-3. Other Articles. These provisions are in addition to, or amendatory of, the provisions of Article 430 and other articles in this Code that apply except as modified in this article. 675-4. Irrigation Cable. (a) Construction. The cable used to interconnect enclosures on the structure of an irrigation machine shall be an assembly of stranded, insulated conductors with nonhygroscopic and nonwicking filler in a core of moisture- and flame-resistant nonmetallic material overlaid with a metallic covering and jacketed with a moisture-, corrosion-, and sunlight-resistant nonmetallic material. The conductor insulation shall be of a type listed in Table 310-13 for an operating temperature of 75°C (167°F) and for use in wet locations. The core insulating material thickness shall not be less than 30 mils (762 micrometers), and the metallic overlay thickness shall not be less than 8 mils (203 micrometers). The jacketing material thickness shall not be less than 50 mils (1.27 mm). A composite of power, control, and grounding conductors in the cable shall be permitted. (b) Alternate Wiring Methods. Other cables listed for the purpose. (c) Supports. Irrigation cable shall be secured by straps, hangers, or similar fittings identified for the purpose and installed as not to damage the I cable. Cable shall be supported at intervals not exceeding 4 feet (1.22 m). (d) Fittings. Fittings shall be used at all points where irrigation cable terminates. The fittings shall be designed for use with the cable and shall be suitable for the conditions of service. 675-5. More than Three Conductors in a Raceway or Cable. The signal and control conductors of a raceway or cable shall not be counted for the purpose of derating the conductors as required in Article 310, Note 8 (a) of Notes to Ampacity Tables of 0 to 2000 Volts. 675-6. Marking on Main Control Panel. The main control panel shall be provided with a nameplate that shall give the following information: (1) the manufacturer's name, the rated voltage, the phase, and the frequency; (2) the current rating of the machine; and (3) the rating of the main disconnecting means and size of overcurrent protection required. 70-692 NATIONAL ELECTRICAL CODE 675-7. Equivalent Current Ratings. Where intermittent duty is not involved, the provisions of Article 430 shall be used for determining ratings for controllers, disconnecting means, conductors, and the like. Where irrigation machines have inherent intermittent duty, the following determinations of equivalent current ratings shall be used. (a) Continuous-Current Rating. The equivalent continuous-current rating for the selection of branch-circuit conductors and overcurrent protection shall be equal to 125 percent of the motor nameplate full-load current rating of the largest motor plus a quantity equal to the sum of each of the motor nameplate full-load current ratings of all remaining motors on the circuit multiplied by the maximum percent duty cycle at which they can continuously operate. (b) Locked-Rotor Current. The equivalent locked-rotor current rating shall be equal to the numerical sum of the locked-rotor current of the two largest motors plus 100 percent of the sum of the motor nameplate full-load current ratings of all the remaining motors on the circuit. 675-8. Disconnecting Means. (a) Main Controller. A controller that is used to start and stop the complete machine shall meet all of the following requirements: (1) An equivalent continuous current rating not less than specified in Section 675-7(a) or 675-22(a). (2) A horsepower rating not less than the value from Table 430-151 based on the equivalent locked-rotor current specified in Section 675-7(b) or 675-22(b). (b) Main Disconnecting Means. The main disconnecting means for the machine shall be at the point of connection of electrical power to the machine or shall be visible and not more than 50 feet (15.2 m) from the machine and shall be readily accessible and capable of being locked in the open position. This disconnecting means shall have a horsepower and current rating not less than required for the main controller. Exception: Circuit breakers without marked horsepower ratings shall be permitted in accordance with Section 430-109. (c) Disconnecting Means for Individual Motors and Controllers. A disconnecting means shall be provided to simultaneously disconnect all ungrounded conductors for each motor and controller and shall be located as required by Article 430, Part I. The disconnecting means shall not be required to be readily accessible. 675-9. Branch-Circuit Conductors. The branch-circuit conductors shall have an ampacity not less than specified in Section 675-7(a) or 675-22(a). 675-10. Several Motors on One Branch Circuit. (a) Protection Required. Several motors, each not exceeding 2-horsepower rating, shall be permitted to be used on an irrigation machine circuit protected at not more than 30 amperes at 600 volts, nominal, or less, provided all of the following conditions are met: