xdy

voltage rating not less than that of the circuit involved, and shall be lockable in accordance with 110.25. The disconnecting means shall have a current rating of not less than 100 percent of the full-load current rating of the motor. For adjustable-speed drive systems, the disconnecting means shall...

voltage rating not less than that of the circuit involved, and shall be lockable in accordance with 110.25. The disconnecting means shall have a current rating of not less than 100 percent of the full-load current rating of the motor. For adjustable-speed drive systems, the disconnecting means shall have a current rating not less than 100 percent of the rated input current of the power conversion equipment. Part XII. Protection of Live Parts — All Voltages 430.231 General. Part XII specifies that live parts shall be protected in an approved manner for the hazard involved. 430.232 Where Required. Exposed live parts of motors and motor controllers operating at 50 volts or more between terminals shall be guarded against accidental contact by enclosure or by location as follows: (1) By installation in a room or enclosure that is accessible only to qualified persons By installation on a suitable balcony, gallery, or platform, elevated and arranged so as to exclude unqualified persons By elevation 2.5 m (8 ft) or more above the floor Exception: Live parts of motors operating at more than 50 volts between terminals shall not require additional guarding for stationary motors that have commutators, collectors, and brush rigging located inside of motor-end brackets and not conductively connected to supply circuits operating at more than 150 volts to ground. 430.233 Guards for Attendants. Where live parts of motors or motor controllers operating at over 50 volts to ground are guarded against accidental contact only by location as specified in 430.232, and where adjustment or other attendance could be necessary during the operation of the apparatus, suitable insulating mats or platforms shall be provided so that the attendant cannot readily touch live parts unless standing on the mats or platforms. Informational Note: See 110.26 and 110.34 for information on working space. Part XIII. Grounding — All Voltages 430.241 General. Part XIII specifies the grounding of exposed non–current-carrying metal parts, likely to become energized, of motor and motor controller frames to limit voltage to ground in the event of accidental contact between energized parts and frames. Insulation, isolation, or guarding are suitable alternatives to grounding of motors under certain conditions. 430.242 Stationary Motors. The frames of stationary motors shall be grounded under any of the following conditions: (1) Where supplied by metal-enclosed wiring Where in a wet location and not isolated or guarded If in a hazardous (classified) location If the motor operates with any terminal at over 150 volts to ground Where the frame of the motor is not grounded, it shall be permanently and effectively insulated from the ground. 430.243 Portable Motors. The frames of portable motors that operate over 150 volts to ground shall be guarded or grounded. Informational Note No. 1: See 250.114(4) for grounding of portable appliances in other than residential occupancies. Informational Note No. 2: See 250.119(D) for color of equipment grounding conductor in flexible cords. Exception No. 1: Listed motor-operated tools, listed motor-operated appliances, and listed motor-operated equipment shall not be required to be grounded where protected by a system of double insulation or its equivalent. Double-insulated equipment shall be distinctively marked. Exception No. 2: Listed motor-operated tools, listed motor-operated appliances, and listed motor-operated equipment connected by a cord and attachment plug other than those required to be grounded in accordance with 250.114. 430.244 Motor Controllers. Motor controller enclosures shall be connected to the equipment grounding conductor regardless of voltage. Motor controller enclosures shall have means for attachment of an equipment grounding conductor termination in accordance with 250.8. Exception: Enclosures attached to ungrounded portable equipment shall not be required to be grounded. 430.245 Method of Grounding. Connection to the equipment grounding conductor shall be done in accordance with Part VI of Article 250. ENHANCED CONTENT Collapse Most motors are subject to vibration. This could require that the wiring to motors that are fixed be installed with a short section of liquidtight flexible metal conduit, liquidtight flexible nonmetallic conduit, or flexible metal conduit to the motor terminal housing to minimize the impact of the vibration. Under these conditions of use, a wire-type equipment grounding conductor (EGC) must be installed (see 250.118). Grounding Through Terminal Housings. Where the wiring to motors is metal-enclosed cable or in metal raceways, junction boxes to house motor terminals shall be provided, and the armor of the cable or the metal raceways shall be connected to them in accordance with 250.96(A) and 250.97. Separation of Junction Box from Motor. The junction box required by 430.245(A) shall be permitted to be separated from the motor by not more than 1.8 m (6 ft) if the leads to the motor are stranded conductors within Type AC cable, interlocked metal tape Type MC cable where listed and identified in accordance with 250.118(A)(10)b., or armored cord or are stranded leads enclosed in liquidtight flexible metal conduit, flexible metal conduit, intermediate metal conduit, rigid metal conduit, or electrical metallic tubing not smaller than metric designator 12 (trade size 3⁄8), with the armor or raceway being connected both to the motor and to the box. Liquidtight flexible nonmetallic conduit and rigid nonmetallic conduit shall be permitted to enclose the leads to the motor if the leads are stranded and the required equipment grounding conductor is connected to both the motor and to the box. Where stranded leads are used, protected as specified above, each strand within the conductor shall be not larger than 10 AWG and shall comply with other requirements of this Code for conductors to be used in raceways. Grounding of Motor Controller-Mounted Devices. Instrument transformer secondaries and exposed non–current-carrying metal or other conductive parts or cases of instrument transformers, meters, instruments, and relays shall be grounded in accordance with 250.170 through 250.178. Part XIV. Tables Table 430.247 Full-Load Current in Amperes, Direct-Current Motors The following values of full-load currents* are for motors running at base speed. Horsepower Armature Voltage Rating 90 Volts 120 Volts 180 Volts 240 Volts 500 Volts 550 Volts The following values of full-load currents are for motors running at base speed. 1⁄ 4 4.0 3.1 2.0 1.6 — — 1⁄ 3 5.2 4.1 2.6 2.0 — — 1⁄ 2 6.8 5.4 3.4 2.7 — — 3⁄ 4 9.6 7.6 4.8 3.8 — — 1 12.2 9.5 6.1 4.7 — — 11⁄2 — 13.2 8.3 6.6 — — 2 — 17 10.8 8.5 — — 3 — 25 16 12.2 — — 5 — 40 27 20 — — 71⁄2 — 58 — 29 13.6 12.2 10 — 76 — 38 18 16 15 — — — 55 27 24 20 — — — 72 34 31 25 — — — 89 43 38 30 — — — 106 51 46 40 — — — 140 67 61 50 — — — 173 83 75 60 — — — 206 99 90 75 — — — 255 123 111 100 — — — 341 164 148 125 — — — 425 205 185 150 — — — 506 246 222 200 — — — 675 330 294 *These are average dc quantities. Table 430.248 Full-Load Currents in Amperes, Single-Phase Alternating-Current Motors The following values of full-load currents are for motors running at usual speeds and motors with normal torque characteristics. The voltages listed are rated motor voltages. The currents listed shall be permitted for system voltage ranges of 110 to 120 and 220 to 240 volts. Horsepower 115 Volts 200 Volts 208 Volts 230 Volts The following values of full-load currents are for motors running at usual speeds and motors with normal torque characteristics. The voltages listed are rated motor voltages. The currents listed shall be permitted for system voltage ranges of 110 to 120 and 220 to 240 volts. 1⁄ 6 4.4 2.5 2.4 2.2 1⁄ 4 5.8 3.3 3.2 2.9 1⁄ 3 7.2 4.1 4.0 3.6 1⁄ 2 9.8 5.6 5.4 4.9 3⁄ 4 13.8 7.9 7.6 6.9 1 16 9.2 8.8 8.0 11⁄2 20 11.5 11.0 10 2 24 13.8 13.2 12 3 34 19.6 18.7 17 5 56 32.2 30.8 28 71⁄2 80 46.0 44.0 40 10 100 57.5 55.0 50 Table 430.249 Full-Load Current, Two-Phase Alternating-Current Motors (4-Wire) Horsepower Induction-Type Squirrel Cage and Wound Rotor (Amperes) 115 Volts 230 Volts 460 Volts 575 Volts 2300 Volts The following values of full-load current are for motors running at speeds usual for belted motors and motors with normal torque characteristics. Current in the common conductor of a 2-phase, 3-wire system will be 1.41 times the value given. The voltages listed are rated motor voltages. The currents listed shall be permitted for system voltage ranges of 110 to 120, 220 to 240, 440 to 480, 550 to 600, and 2300 to 2400 volts. 1⁄ 2 4.0 2.0 1.0 0.8 — 3⁄ 4 4.8 2.4 1.2 1.0 — 1 6.4 3.2 1.6 1.3 — 11⁄2 9.0 4.5 2.3 1.8 — 2 11.8 5.9 3.0 2.4 — 3 — 8.3 4.2 3.3 — 5 — 13.2 6.6 5.3 — 71⁄2 — 19 9.0 8.0 — 10 — 24 12 10 — 15 — 36 18 14 — 20 — 47 23 19 — 25 — 59 29 24 — 30 — 69 35 28 — 40 — 90 45 36 — 50 — 113 56 45 — 60 — 133 67 53 14 75 — 166 83 66 18 100 — 218 109 87 23 125 — 270 135 108 28 150 — 312 156 125 32 200 — 416 208 167 43 Table 430.250 Full-Load Current, Three-Phase Alternating-Current Motors Horsepower Induction-Type Squirrel Cage and Wound Rotor (Amperes) Synchronous-Type Unity Power Factor* (Amperes) 115 Volts 200 Volts 208 Volts 230 Volts 460 Volts 575 Volts 2300 Volts 230 Volts 460 Volts 575 Volts 2300 Volts The following values of full-load currents are typical for motors running at speeds usual for belted motors and motors with normal torque characteristics. The voltages listed are rated motor voltages. The currents listed shall be permitted for system voltage ranges of 110 to 120, 220 to 240, 440 to 480, 550 to 600, and 2300 to 2400 volts. 1⁄ 2 4.4 2.5 2.4 2.2 1.1 0.9 — — — — — 3⁄ 4 6.4 3.7 3.5 3.2 1.6 1.3 — — — — — 1 8.4 4.8 4.6 4.2 2.1 1.7 — — — — — 11⁄2 12.0 6.9 6.6 6.0 3.0 2.4 — — — — — 2 13.6 7.8 7.5 6.8 3.4 2.7 — — — — — 3 — 11.0 10.6 9.6 4.8 3.9 — — — — — 5 — 17.5 16.7 15.2 7.6 6.1 — — — — — 71⁄2 — 25.3 24.2 22 11 9 — — — — — 10 — 32.2 30.8 28 14 11 — — — — — 15 — 48.3 46.2 42 21 17 — — — — — 20 — 62.1 59.4 54 27 22 — — — — — 25 — 78.2 74.8 68 34 27 — 53 26 21 — 30 — 92 88 80 40 32 — 63 32 26 — 40 — 120 114 104 52 41 — 83 41 33 — 50 — 150 143 130 65 52 — 104 52 42 — 60 — 177 169 154 77 62 16 123 61 49 12 75 — 221 211 192 96 77 20 155 78 62 15 100 — 285 273 248 124 99 26 202 101 81 20 125 — 359 343 312 156 125 31 253 126 101 25 150 — 414 396 360 180 144 37 302 151 121 30 200 552 528 480 240 192 49 400 201 161 40 250 — — — — 302 242 60 — — — — 300 — — — — 361 289 72 — — — — 350 — — — — 414 336 83 — — — — 400 — — — — 477 382 95 — — — — 450 — — — — 515 412 103 — — — — 500 — — — — 590 472 118 — — — — *For 90 and 80 percent power factor, the figures shall be multiplied by 1.1 and 1.25, respectively. Table 430.251(A) Conversion Table of Single-Phase Locked-Rotor Currents for Selection of Disconnecting Means and Controllers as Determined from Horsepower and Voltage Rating For use only with 430.110, 440.12, 440.41, and 455.8(C). Rated Horsepower Maximum Locked-Rotor Current in Amperes, Single-Phase 115 Volts 208 Volts 230 Volts For use only with 430.110, 440.12, 440.41, and 455.8(C). 1⁄ 2 58.8 32.5 29.4 3⁄ 4 82.8 45.8 41.4 1 96 53 48 11⁄2 120 66 60 2 144 80 72 3 204 113 102 5 336 186 168 71⁄2 480 265 240 10 1000 332 300 Table 430.251(B) Conversion Table of Polyphase Design B, C, and D Maximum Locked-Rotor Currents for Selection of Disconnecting Means and Controllers as Determined from Horsepower and Voltage Rating and Design Letter For use only with 430.110, 440.12, 440.41, and 455.8(C). Rated Horsepower Maximum Motor Locked-Rotor Current in Amperes, Two- and Three-Phase, Design B, C, and D 115 Volts 200 Volts 208 Volts 230 Volts 460 Volts 575 Volts B, C, D B, C, D B, C, D B, C, D B, C, D B, C, D For use only with 430.110, 440.12, 440.41, and 455.8(C). 1⁄ 2 40 23 22.1 20 10 8 3⁄ 4 50 28.8 27.6 25 12.5 10 1 60 34.5 33 30 15 12 11⁄2 80 46 44 40 20 16 2 100 57.5 55 50 25 20 3 — 73.6 71 64 32 25.6 5 — 105.8 102 92 46 36.8 71⁄2 — 146 140 127 63.5 50.8 10 — 186.3 179 162 81 64.8 15 — 267 257 232 116 93 20 — 334 321 290 145 116 25 — 420 404 365 183 146 30 — 500 481 435 218 174 40 — 667 641 580 290 232 50 — 834 802 725 363 290 60 — 1001 962 870 435 348 75 — 1248 1200 1085 543 434 100 — 1668 1603 1450 725 580 125 — 2087 2007 1815 908 726 150 — 2496 2400 2170 1085 868 200 — 3335 3207 2900 1450 1160 250 — — — — 1825 1460 300 — — — — 2200 1760 350 — — — — 2550 2040 400 — — — — 2900 2320 450 — — — — 3250 2600 500 — — — — 3625 2900 Design A motors are not limited to a maximum starting current or locked rotor current. Article 440 Air-Conditioning and Refrigerating Equipment ENHANCED CONTENT Collapse Article 440 provides special considerations necessary for the branch circuits supplying hermetic refrigerant motor-compressors and is in addition to or amendatory of the requirements of Article 430 and other applicable articles. However, many requirements for disconnecting means, controllers, single or group installations, and sizing of conductors, for example, are the same as or similar to those applied in Article 430. The rules for sizing conductors and overcurrent protection of feeder conductors supplying multiple air-conditioning or refrigeration units employing hermetic refrigerant motor-compressors are the same rules from Parts II and V in Article 430 that are used for sizing conductors and overcurrent protection for feeder circuits supplying multiple motors. Part I. General 440.1 Scope. This article applies to electric motor-driven air-conditioning and refrigerating equipment and to the branch circuits and controllers for such equipment. It provides for the special considerations necessary for circuits supplying hermetic refrigerant motor-compressors and for any air-conditioning or refrigerating equipment that is supplied from a branch circuit that supplies a hermetic refrigerant motor-compressor. ENHANCED CONTENT Collapse Definitions. Each of the following terms has a definition in Article 100 that is unique to its use in Article 440: Branch-circuit selection current Leakage-current detector-interrupter Rated-load current 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 motor-compressor nameplate. Where a thermal protector complying with 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 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 440.52(A)(4) and (B)(4) is specified, the equipment nameplate shall be appropriately marked. 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, the maximum rating of the branch-circuit short-circuit and ground-fault protective device, and the short-circuit current rating of the motor controllers or industrial control panel. The ampacity shall be calculated by using Part IV and counting all the motors and other loads that will be operated at the same time. The branch-circuit short-circuit and ground-fault protective device rating shall not exceed the value calculated by using Part III. Multimotor or combination-load 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: The minimum supply circuit conductor ampacity and the maximum rating of the branch-circuit short-circuit and ground-fault protective device shall not be required to be marked on a room air conditioner complying with 440.62(A). Exception No. 3: Multimotor and combination-load equipment used in one- and two-family dwellings or cord-and-attachment-plug-connected equipment shall not be required to be marked with a short-circuit current rating. ENHANCED CONTENT Collapse Motor controllers or control panels associated with multi-motor and combination-load air-conditioning and refrigerating equipment are required by 440.4(B) to be marked with the short-circuit current rating. Where air-conditioning equipment is installed at large commercial, institutional, and industrial complexes, the controllers and control panels of air-conditioning and refrigerating equipment are often supplied from a point on the electrical distribution system where significant short-circuit current is available. As is the case with any electrical installation where high levels of short-circuit current are available, the short-circuit current rating marked on the air-conditioning equipment controllers and control panels provides those responsible for designing and approving the electrical installation with the necessary information to ensure compliance with the requirements of 110.9 and 110.10. Multi-motor and combination-load air-conditioning equipment used in one- and two-family dwellings and cord-and-attachment-plug-connected air-conditioning equipment are not required to be marked with their short-circuit current ratings. See also 430.8 for a similar requirement for marking the short-circuit current rating on motor controllers. Branch-Circuit Selection Current. A hermetic refrigerant motor-compressor, or equipment containing such a compressor, having a protection system that is approved for use with the motor-compressor that it protects and that permits continuous current in excess of the specified percentage of nameplate rated-load current given in 440.52(B)(2) or (B)(4) shall also be marked with a branch-circuit selection current that complies with 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 manufacturer’s name, trademark, or symbol; identifying designation; voltage; phase; full-load and locked-rotor current (or horsepower) rating; and 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 Table 310.16 through Table 310.19 or calculated in accordance with 310.14 as applicable. The required ampacity of conductors and rating of equipment shall be determined according to 440.6(A) and 440.6(B). 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 branch-circuit 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. 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: For cord-and-plug-connected equipment, the nameplate marking shall be used in accordance with 440.22(B), Exception No. 2. (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 430.24, 430.53(B) and 430.53(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 highest rated-load current, only one of them shall be considered as the highest rated (largest) motor. For other than hermetic refrigerant motor-compressors, and fan or blower motors as covered in 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 430.248, Table 430.249, or Table 430.250. Exception: Where so marked, the branch-circuit selec