Resolución 2535: adopta el Código Eléctrico Nacional, versión 1993. (Sustituye el Anejo A del Reglamento 4435)

440-4. Marking on Hermetic Refrigerant Motor-Compressors and Equipment. (a) Hermetic Refrigerant Motor-Compressor Nameplate. A hermetic refrigerant motor-compressor shall be provided with a nameplate that shall indicate the manufacturer's name, trademark, or symbol; identifying designation; phase; voltage; and frequency. The rated-load current in amperes of the motor-compressor shall be marked by the equipment manufacturer on either or both the motor-compressor nameplate and the nameplate of the equipment in which the motor-compressor is used. The locked-rotor current of each single-phase motor-compressor having a rated-load current of more than 9 amperes at 115 volts, or more than 4.5 amperes at 230 volts, and each polyphase motor-compressor shall be marked on the motorcompressor nameplate. Where a thermal protector complying with Sections 440-52(a)(2) and (b)(2) is used, the motor-compressor nameplate or the equipment nameplate shall be marked with the words "thermally protected. Where a protective system complying with Sections 440-52(a)(4) and (b)(4) is used and is furnished with the equipment, the equipment nameplate shall be marked with the words, "thermally protected system." Where a protective system complying with Sections 440-52(a)(4) and (b)(4) is specified, the equipment nameplate shall be appropriately marked. (b) Multimotor and Combination-Load Equipment. Multimotor and combination-load equipment shall be provided with a visible nameplate marked with the maker's name, the rating in volts, frequency and number of phases, minimum supply circuit conductor ampacity, and the maximum rating of the branch-circuit short-circuit and ground-fault protective device. The ampacity shall be calculated by using Part D and counting all the motors and other loads that will be operated at the same time. The branchcircuit short-circuit and ground-fault protective device rating shall not exceed the value calculated by using Part C. Multimotor or combinationload equipment for use on two or more circuits shall be marked with the above information for each circuit. Exception No. 1: Multimotor and combination-load equipment that is suitable under the provisions of this article for connection to a single 15- or 20-ampere, 120-volt, or a 15-ampere, 208- or 240-volt, single-phase branch circuit shall be permitted to be marked as a single load. Exception No. 2: Room air conditioners as provided in Part G of Article 440. (c) Branch-Circuit Selection Current. A hermetic refrigerant motorcompressor, or equipment containing such a compressor, having a protection system that is approved for use with the motor-compressor that it pro- ARTICLE 440 - AIR CONDITIONING EQUIPMENT 70-433 tects and that permits continuous current in excess of the specified percentage of nameplate rated-load current given in Section 440-52(b)(2) or (b)(4), shall also be marked with a branch-circuit selection current that complies with Section 440-52(b)(2) or (b)(4). This marking shall be provided by the equipment manufacturer and shall be on the nameplate(s) where the rated-load current(s) appears. 440-5. Marking on Controllers. A controller shall be marked with the maker's name, trademark, or symbol; identifying designation; the voltage; phase; full-load and locked-rotor current (or horsepower) rating; and such other data as may be needed to properly indicate the motor-compressor for which it is suitable. 440-6. Ampacity and Rating. The size of conductors for equipment covered by this article shall be selected from Tables 310-16 through 310-19 or calculated in accordance with Section 310-15 as applicable. The required ampacity of conductors and rating of equipment shall be determined as follows. (a) Hermetic Refrigerant Motor-Compressor. For a hermetic refrigerant motor-compressor, the rated-load current marked on the nameplate of the equipment in which the motor-compressor is employed shall be used in determining the rating or ampacity of the disconnecting means, the branchcircuit conductors, the controller, the branch-circuit short-circuit and ground-fault protection, and the separate motor overload protection. Where no rated-load current is shown on the equipment nameplate, the rated-load current shown on the compressor nameplate shall be used. For disconnecting means and controllers, see also Sections 440-12 and 440-41. Exception No. 1: Where so marked, the branch-circuit selection current shall be used instead of the rated-load current to determine the rating or ampacity of the disconnecting means, the branch-circuit conductors, the controller, and the branch-circuit short-circuit and ground-fault protection. Exception No. 2: As permitted in Section 440-22(b) for branch-circuit short-circuit and ground-fault protection of cord- and plug-connected equipment. (b) Multimotor Equipment. For multimotor equipment employing a shaded-pole or permanent split-capacitor-type fan or blower motor, the full-load current for such motor marked on the nameplate of the equipment in which the fan or blower motor is employed shall be used instead of the horsepower rating to determine the ampacity or rating of the disconnecting means, the branch-circuit conductors, the controller, the branch-circuit short-circuit and ground-fault protection, and the separate overload protection. This marking on the equipment nameplate shall not be less than the current marked on the fan or blower motor nameplate. 440-7. Highest Rated (Largest) Motor. In determining compliance with this article and with Sections 430-24, 430-53(b) and (c), and 430-62(a), the highest rated (largest) motor shall be considered to be the motor that has the highest rated-load current. Where two or more motors have the same rated-load current, only one of them shall be considered as the highest rated (largest) motor. For other than hermetic refrigerant motor- 70-434 NATIONAL ELECTRICAL CODE compressors, and fan or blower motors as covered in Section 440-6(b), the full-load current used to determine the highest rated motor shall be the equivalent value corresponding to the motor horsepower rating selected from Table 430-148, 430-149, or 430-150. Exception: Where so marked, the branch-circuit selection current shall be used instead of the rated-load current in determining the highest rated (largest) motor-compressor. 440-8. Single Machine. An air-conditioning or refrigerating system shall be considered to be a single machine under the provisions of Section 430- 87, Exception and Section 430-112, Exception. The motors shall be permitted to be located remotely from each other. B. Disconnecting Means 440-11. General. The provisions of Part B are intended to require disconnecting means capable of disconnecting air-conditioning and refrigerating equipment including motor-compressors, and controllers, from the circuit feeder. See Diagram 430-1. 440-12. Rating and Interrupting Capacity. (a) Hermetic Refrigerant Motor-Compressor. A disconnecting means serving a hermetic refrigerant motor-compressor shall be selected on the basis of the nameplate rated-load current or branch-circuit selection current, whichever is greater, and locked-rotor current, respectively, of the motor-compressor as follows: (1) The ampere rating shall be at least 115 percent of the nameplate rated-load current or branch-circuit selection current, whichever is greater. (2) To determine the equivalent horsepower in complying with the requirements of Section 430-109, the horsepower rating shall be selected from Table 430-148, 430-149, or 430-150 corresponding to the rated-load current or branch-circuit selection current, whichever is greater, and also the horsepower rating from Table 430-151 corresponding to the lockedrotor current. In case the nameplate rated-load current or branch-circuit selection current and locked-rotor current do not correspond to the currents shown in Table 430-148, 430-149, 430-150, or 430-151, the horsepower rating corresponding to the next higher value shall be selected. In case different horsepower ratings are obtained when applying these tables, a horsepower rating at least equal to the larger of the values obtained shall be selected. (b) Combination Loads. Where one or more hermetic refrigerant motor-compressors are used together or are used in combination with other motors or loads, and where the combined load may be simultaneous on a single disconnecting means, the rating for the combined load shall be determined as follows: (1) The horsepower rating of the disconnecting means shall be determined from the summation of all currents, including resistance loads, at the rated-load condition and also at the locked-rotor condition. The combined ARTICLE 440 - AIR CONDITIONING EQUIPMENT 70-435 rated-load current and the combined locked-rotor current so obtained shall be considered as a single motor for the purpose of this requirement as follows: a. The full-load current equivalent to the horsepower rating of each motor, other than a hermetic refrigerant motor-compressor, and fan or blower motors as covered in Section 440-6(b) shall be selected from Table 430-148, 430-149, or 430-150. These full-load currents shall be added to the motor-compressor rated-load current(s) or branchcircuit selection current(s), whichever is greater, and to the rating in amperes of other loads to obtain an equivalent full-load current for the combined load. b. The locked-rotor current equivalent to the horsepower rating of each motor, other than a hermetic refrigerant motor-compressor, shall be selected from Table 430-151, and, for fan and blower motors of the shaded-pole or permanent split-capacitor type marked with the lockedrotor current, the marked value shall be used. The locked-rotor currents shall be added to the motor-compressor locked-rotor current(s) and to the rating in amperes of other loads to obtain an equivalent locked-rotor current for the combined load. Where two or more motors or other loads such as resistance heaters, or both, cannot be started simultaneously, appropriate combinations of locked-rotor and rated-load current or branch-circuit selection current, whichever is greater, shall be an acceptable means of determining the equivalent locked-rotor current for the simultaneous combined load. Exception: Where part of the concurrent load is a resistance load and the disconnecting means is a switch rated in horsepower and amperes, the switch used shall be permitted to have a horsepower rating not less than the combined load to the motor-compressor(s) and other motor(s) at the locked-rotor condition, if the ampere rating of the switch is not less than this locked-rotor load plus the resistance load. (2) The ampere rating of the disconnecting means shall be at least 115 percent of the summation of all currents at the rated-load condition determined in accordance with Section 440-12(b)(1). (c) Small Motor-Compressors. For small motor-compressors not having the locked-rotor current marked on the nameplate, or for small motors not covered by Table 430-147, 430-148, 430-149, or 430-150, the lockedrotor current shall be assumed to be six times the rated-load current. See