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

(4) A protective system in accordance with Section 440-52(a)(4) and that will not permit a continuous current in excess of 156 percent of the marked rated-load current or branch-circuit selection current. 440-53. Overload Relays. Overload relays and other devices for motor overload protection, that are not capable of opening short circuits, shall be protected by fuses or inverse time circuit breakers with ratings or settings in accordance with Part C unless approved for group installation or for part-winding motors and marked to indicate the maximum size of fuse or inverse time circuit breaker by which they shall be protected. Exception: The fuse or inverse time circuit breaker size marking shall be permitted on the nameplate of approved equipment in which the overload relay or other overload device is used. 440-54. Motor-Compressors and Equipment on 15- or 20-Ampere Branch Circuits - Not Cord- and Attachment Plug-Connected. Overload protection for motor-compressors and equipment used on 15- or 20-ampere 120- volt, or 15-ampere 208- or 240-volt single-phase branch circuits as permitted in Article 210 shall be permitted as indicated in (a) and (b) below. (a) Overload Protection. The motor-compressor shall be provided with overload protection selected as specified in Section 440-52(a). Both the controller and motor overload protective device shall be approved for installation with the short-circuit and ground-fault protective device for the branch circuit to which the equipment is connected. (b) Time Delay. The short-circuit and ground-fault protective device protecting the branch circuit shall have sufficient time delay to permit the motor-compressor and other motors to start and accelerate their loads. 440-55. Cord- and Attachment Plug-Connected Motor-Compressors and Equipment on 15- or 20-Ampere Branch Circuits. Overload protection for motor-compressors and equipment that are cord- and attachment plugconnected and used on 15- or 20-ampere 120-volt, or 15-ampere 208- or 240-volt single-phase branch circuits as permitted in Article 210 shall be permitted as indicated in (a), (b), and (c) below. (a) Overload Protection. The motor-compressor shall be provided with overload protection as specified in Section 440-52(a). Both the controller and the motor overload protective device shall be approved for installation with the short-circuit and ground-fault protective device for the branch circuit to which the equipment is connected. (b) Attachment Plug and Receptacle Rating. The rating of the attachment plug and receptacle shall not exceed 20 amperes at 125 volts or 15 amperes at 250 volts. (c) Time Delay. The short-circuit and ground-fault protective device protecting the branch circuit shall have sufficient time delay to permit the motor-compressor and other motors to start and accelerate their loads. ARTICLE 440 - AIR CONDITIONING EQUIPMENT 70-441 G. Provisions for Room Air Conditioners 440-60. General. The provisions of Part G shall apply to electrically energized room air conditioners that control temperature and humidity. For the purpose of Part G, a room air conditioner (with or without provisions for heating) shall be considered as an alternating-current appliance of the aircooled window, console, or in-wall type that is installed in the conditioned room and that incorporates a hermetic refrigerant motor-compressor(s). The provisions of Part G cover equipment rated not over 250 volts, single phase, and such equipment shall be permitted to be cord- and attachment plug-connected. A room air conditioner that is rated three phase or rated over 250 volts shall be directly connected to a wiring method recognized in Chapter 3, and provisions of Part G shall not apply. 440-61. Grounding. Room air conditioners shall be grounded in accordance with Sections 250-42, 250-43, and 250-45. 440-62. Branch-Circuit Requirements. (a) Room Air Conditioner as a Single Motor Unit. A room air conditioner shall be considered as a single motor unit in determining its branchcircuit requirements where all the following conditions are met: (1) It is cord- and attachment plug-connected. (2) Its rating is not more than 40 amperes and 250 volts, single phase. (3) Total rated-load current is shown on the room air-conditioner nameplate rather than individual motor currents, and (4) The rating of the branch-circuit short-circuit and ground-fault protective device does not exceed the ampacity of the branch-circuit conductors or the rating of the receptacle, whichever is less. (b) Where No Other Loads Are Supplied. The total marked rating of a cord- and attachment plug-connected room air conditioner shall not exceed 80 percent of the rating of a branch circuit where no other loads are supplied. (c) Where Lighting Units or Other Appliances Are also Supplied. The total marked rating of a cord-and attachment plug-connected room air conditioner shall not exceed 50 percent of the rating of a branch circuit where lighting units or other appliances are also supplied. 440-63. Disconnecting Means. An attachment plug and receptacle shall be permitted to serve as the disconnecting means for a single-phase room air conditioner rated 250 volts or less if (1) the manual controls on the room air conditioner are readily accessible and located within 6 feet (1.83 m) of the floor or (2) an approved manually operable switch is installed in a readily accessible location within sight from the room air conditioner. 440-64. Supply Cords. Where a flexible cord is used to supply a room air conditioner, the length of such cord shall not exceed (1) 10 feet (3.05 m) for a nominal, 120-volt rating or (2) 6 feet (1.83 m) for a nominal, 208- or 240- volt rating. 70-442 NATIONAL ELECTRICAL CODE