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tion current shall be used instead of the rated-load current in determining the highest rated (largest) motor-compressor. 440.8 Single Machine and Location. An air-conditioning or refrigerating system shall be considered to be a single machine under the provisions of 430.87, Exception No. 1, and 430...

tion current shall be used instead of the rated-load current in determining the highest rated (largest) motor-compressor. 440.8 Single Machine and Location. An air-conditioning or refrigerating system shall be considered to be a single machine under the provisions of 430.87, Exception No. 1, and 430.112, Exception. The motors shall be permitted to be located remotely from each other. Air-conditioning and refrigeration equipment shall not be installed within a zone measured 900 mm (3 ft) horizontally and 2.5 m (8 ft) vertically from the top of a bathtub rim or shower stall threshold. The zone shall be all-encompassing and include the space directly over the tub or shower stall. 440.9 Grounding and Bonding. Where equipment is installed outdoors on a roof, an equipment grounding conductor of the wire type shall be installed in outdoor portions of metallic raceway systems that use compression-type fittings. ENHANCED CONTENT Collapse Metal raceway systems with compression fittings listed for use in wet locations that are installed on rooftops to supply air-conditioning and refrigeration equipment could be subject to movement and physical damage. This is a result of rooftop activities such as snow removal or roof repair/replacement. These activities can lead to inadvertent separation of the raceway system, compromising the ground-fault return path. The installation of a wire-type equipment grounding conductor provides redundancy of the ground-fault return path to facilitate the operation of the circuit overcurrent protective device (OCPD) in the event of a line-to-ground fault at the air-conditioning or refrigeration equipment. 440.10 Short-Circuit Current Rating. (A) Installation. Motor controllers or industrial control panels of multimotor and combination-load equipment shall not be installed where the available fault current exceeds its short-circuit current rating as marked in accordance with 440.4(B). Documentation. When motor controllers or industrial control panels of multimotor and combination-load equipment are required to be marked with a short circuit current rating, the available fault current and the date the available fault current calculation was performed shall be documented and made available to those authorized to inspect, install, or maintain the installation. Part II. Disconnecting Means 440.11 General. Disconnecting means shall be capable of disconnecting air-conditioning and refrigerating equipment, including motor-compressors and controllers, from the circuit conductors. If the disconnecting means is readily accessible to unqualified persons, any enclosure door or hinged cover of a disconnecting means enclosure that exposes energized parts when open shall require a tool to open or be capable of being locked. 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. Ampere Rating. The ampere rating shall be at least 115 percent of the nameplate rated-load current or branch-circuit selection current, whichever is greater. Exception: A listed unfused motor circuit switch, without fuseholders, having a horsepower rating not less than the equivalent horsepower determined in accordance with 440.12(A)(2) shall be permitted to have an ampere rating less than 115 percent of the specified current. (2) Equivalent Horsepower. To determine the equivalent horsepower in complying with the requirements of 430.109, the horsepower rating shall be selected from Table 430.248, Table 430.249, or Table 430.250 corresponding to the rated-load current or branch-circuit selection current, whichever is greater, and also the horsepower rating from Table 430.251(A) or Table 430.251(B) corresponding to the locked-rotor 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 430.248, Table 430.249, Table 430.250, Table 430.251(A), or Table 430.251(B), 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. Combination Loads. Where the combined load of two or more hermetic refrigerant motor-compressors or one or more hermetic refrigerant motor-compressor with other motors or loads may be simultaneous on a single disconnecting means, the rating for the disconnecting means shall be determined in accordance with 440.12(B)(1) and (B)(2). Horsepower Rating. The horsepower rating of the disconnecting means shall be determined from the sum of all currents, including resistance loads, at the rated-load condition and also at the locked-rotor condition. The combined 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 required by 440.12(B)(1)(a) and (B)⁠(1)⁠(b). 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 440.6(B) shall be selected from Table 430.248, Table 430.249, or Table 430.250. These full-load currents shall be added to the motor-compressor rated-load current(s) or branch-circuit 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. The locked-rotor current equivalent to the horsepower rating of each motor, other than a hermetic refrigerant motor-compressor, shall be selected from Table 430.251(A) or Table 430.251(B), and, for fan and blower motors of the shaded-pole or permanent split-capacitor type marked with the locked-rotor 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) Full-Load Current Equivalent. The ampere rating of the disconnecting means shall be at least 115 percent of the sum of all currents at the rated-load condition determined in accordance with 440.12(B)(1). Exception: A listed unfused motor circuit switch, without fuseholders, having a horsepower rating not less than the equivalent horsepower determined by 440.12(B)(1) shall be permitted to have an ampere rating less than 115 percent of the sum of all currents. (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 430.247, Table 430.248, Table 430.249, or Table 430.250, the locked-rotor current shall be assumed to be six times the rated-load current. Disconnecting Means. Every disconnecting means in the refrigerant motor-compressor circuit between the point of attachment to the feeder and the point of connection to the refrigerant motor-compressor shall comply with the requirements of 440.12. Disconnecting Means Rated in Excess of 100 Horsepower. Where the rated-load or locked-rotor current as determined above would indicate a disconnecting means rated in excess of 100 hp, 430.109(E) shall apply. 440.13 Cord-Connected Equipment. For cord-connected equipment such as room air conditioners, household refrigerators and freezers, drinking water coolers, and beverage dispensers, a separable connector or an attachment plug and receptacle shall be permitted to serve as the disconnecting means. Informational Note: See 440.63 for room air conditioners. 440.14 Location. Disconnecting means shall be located within sight from, and readily accessible from, the air-conditioning or refrigerating equipment. The disconnecting means shall be permitted to be installed on or within the air-conditioning or refrigerating equipment. Disconnecting means shall meet the working space requirements of 110.26(A). The disconnecting means shall not be located on panels that are designed to allow access to the air-conditioning or refrigeration equipment or where it obscures the equipment nameplate(s). Exception No. 1: Where the disconnecting means provided in accordance with 430.102(A) is lockable in accordance with 110.25 and the refrigerating or air-conditioning equipment is essential to an industrial process in a facility with written safety procedures, and where the conditions of maintenance and supervision ensure that only qualified persons service the equipment, a disconnecting means within sight from the equipment shall not be required. Exception No. 2: Where an attachment plug and receptacle serve as the disconnecting means in accordance with 440.13, their location shall be accessible but shall not be required to be readily accessible. Informational Note: See Parts VII and IX of Article 430 for additional requirements. ENHANCED CONTENT Collapse Exception No. 1 accommodates special conditions associated with process refrigerating equipment. Typically, this equipment is very large, so rated disconnects might not be available. Additionally, this equipment could be in a hazardous (classified) location, and locating the disconnecting means within sight of the motor could introduce additional hazards. The means to lock the disconnecting means in the open position must remain in place with or without the lock installed. The means to lock the disconnecting means in the open position must remain in place with or without the lock installed. An example of locking hardware meeting this requirement is shown below. (Courtesy of Schneider Electric) The references to Parts VII and IX of Article 430 in Informational Note No. 1 are intended to call attention to the additional disconnect location requirements in 430.102, 430.107, and 430.113. The requirement of 440.14 mandates that the equipment disconnecting means be within sight from and readily accessible from the equipment, even if a remote disconnect is capable of being locked in the “open” position, in accordance with the exception to 430.102(B)(2). This special requirement for air-conditioning and refrigerating equipment covered by Article 440 is more stringent than the requirements in Article 430. It provides protection for service personnel working on equipment located in attics, on roofs, or outside in a remote location where it is difficult to gain access to a remote lockable disconnect. Part III. Branch-Circuit Short-Circuit and Ground-Fault Protection 440.21 General. Part III specifies devices intended to protect the branch-circuit conductors, control apparatus, and motors in circuits supplying hermetic refrigerant motor-compressors against overcurrent due to short circuits and ground faults. They are in addition to or amendatory of the overcurrent protection requirements found elsewhere in this Code. ENHANCED CONTENT Collapse Where an air conditioner is listed by a qualified electrical testing laboratory with a nameplate that reads “maximum fuse size,” the listing restricts the use of the unit to fuse protection only and does not cover its use with circuit breakers. If the air conditioner has been evaluated for both fuses and circuit breakers, it is marked to indicate that both types of protective devices are acceptable. Molded-case circuit breakers, evaluated to UL 489, Molded-Case Circuit Breakers, Molded-Case Switches and Circuit-Breaker Enclosures, are certified for group motor protection in accordance with 430.53. The equipment covered by Article 440 quite often consists of hermetic refrigerant motors plus other types of motors, equipment, and controls. If supplemental overcurrent protection is provided within the heating, air-conditioning, and refrigeration (HACR) equipment control panel, the manufacturer will have marked the equipment with specific information on the type of branch-circuit overcurrent protective device that can be used on the line side of the HACR unit in order to provide the necessary level of short-circuit and ground-fault protection for the equipment and controls internal to the HACR unit. Section 110.3(B) requires listed equipment to be installed and used in accordance with instructions included in the listing. In the case of air-conditioning equipment, it is important to carefully read the nameplate so that the correct type of short-circuit, ground-fault protective device is selected. The acronym “HACR” as a prefix to circuit breaker may still be found on the nameplates of legacy HACR equipment. This abbreviation indicated that the HACR equipment manufacturer wanted to specify that if circuit breakers were used, only those evaluated for group motor applications were suitable for the branch-circuit short-circuit, and ground-fault protection. However, because UL 489 required all circuit breakers to be evaluated for protection of group installations, the HACR marking on circuit breakers was not required by the product standard. However, because legacy HACR equipment still includes nameplates specifying the specially marked circuit breakers, some circuit breaker manufacturers continue to mark their molded case circuit breakers with “HACR Type,” even though it is not required by the product certification standard. Illustrated below are three examples of supply circuit configurations in which fuses can be used to protect HACR equipment if such protection is specified on the equipment nameplate. Current-limiting overcurrent devices, which may reduce the amount of fault current to which the equipment is subjected, can be installed in the branch circuit supplying the equipment. See also Article 100 for the definition of current-limiting overcurrent protective device and its enhanced content explaining short-circuit damage. For the installation and use of listed or labeled equipment and the selection of OCPDs (such as fuses and circuit breakers), see 110.3(B) and 110.10 and its enhanced content. 440.22 Application and Selection. Rating or Setting for Individual Motor-Compressor. The motor-compressor branch-circuit short-circuit and ground-fault protective device shall be capable of carrying the starting current of the motor. A protective device having a rating or setting not exceeding 175 percent of the motor-compressor rated-load current or branch-circuit selection current, whichever is greater, shall be permitted. Exception No. 1: If the values for branch-circuit short-circuit and ground-fault protection in accordance with 440.22(A) do not correspond to the standard sizes or ratings of fuses, nonadjustable circuit breakers, thermal protective devices, or available settings of adjustable circuit breakers, a higher size, rating, or available setting that does not exceed the next higher standard ampere rating shall be permitted. Exception No. 2: If the values for branch-circuit short-circuit and ground-fault protection in accordance with 440.22(A) or the rating modified by Exception No. 1 is not sufficient for the starting current of the motor, the rating or setting shall be permitted to be increased but shall not exceed 225 percent of the motor rated-load current or branch-circuit selection current, whichever is greater. Exception No. 3: The rating of the branch-circuit short-circuit and ground-fault protective device shall not be required to be less than 15 amperes. (B) Rating or Setting for Equipment. The equipment branch-circuit short-circuit and ground-fault protective device shall be capable of carrying the starting current of the equipment. Where the hermetic refrigerant motor-compressor is the only load on the circuit, the protection shall comply with 440.22(A). Where the equipment incorporates more than one hermetic refrigerant motor-compressor or a hermetic refrigerant motor-compressor and other motors or other loads, the equipment short-circuit and ground-fault protection shall comply with 430.53 and 440.22(B)(1) and (B)(2). Motor-Compressor Largest Load. Where a hermetic refrigerant motor-compressor is the largest load connected to the circuit, the rating or setting of the branch-circuit short-circuit and ground-fault protective device shall not exceed the value specified in 440.22(A) for the largest motor-compressor plus the sum of the rated-load current or branch-circuit selection current, whichever is greater, of the other motor-compressor(s) and the ratings of the other loads supplied. Motor-Compressor Not Largest Load. Where a hermetic refrigerant motor-compressor is not the largest load connected to the circuit, the rating or setting of the branch-circuit short-circuit and ground-fault protective device shall not exceed a value equal to the sum of the rated-load current or branch-circuit selection current, whichever is greater, rating(s) for the motor-compressor(s) plus the value specified in 430.53(C)(4) where other motor loads are supplied, or the value specified in 240.4 where only nonmotor loads are supplied in addition to the motor-compressor(s). Exception No. 1: Equipment that starts and operates on a 15- or 20-ampere 120-volt, or 15-ampere 208- or 240-volt single-phase branch circuit, shall be permitted to be protected by the 15- or 20-ampere overcurrent device protecting the branch circuit, but if the maximum branch-circuit short-circuit and ground-fault protective device rating marked on the equipment is less than these values, the circuit protective device shall not exceed the value marked on the equipment nameplate. Exception No. 2: The nameplate marking of cord-and-plug-connected equipment rated not greater than 250 volts, single-phase, such as household refrigerators and freezers, drinking water coolers, and beverage dispensers, shall be used in determining the branch-circuit requirements, and each unit shall be considered as a single motor unless the nameplate is marked otherwise. (C) Protective Device Rating Not to Exceed the Manufacturer’s Values. Where maximum protective device ratings shown on a manufacturer’s overload relay table for use with a motor controller are less than the rating or setting selected in accordance with 440.22(A) and (B), the protective device rating shall not exceed the manufacturer’s values marked on the equipment. Part IV. Circuit Conductors 440.31 General. Part IV and adjustments made in accordance with Part III of Article 310 specify ampacities of conductors required to carry the motor current without overheating under the conditions specified, except as modified in 440.6(A), Exception No. 1. These articles shall not apply to integral conductors of motors, to motor controllers and the like, or to conductors that form an integral part of approved equipment. 440.32 Single Motor-Compressor. Branch-circuit conductors supplying a single motor-compressor shall have an ampacity not less than the greater of the following: (1) 125 percent of the motor-compressor rated-load current 125 percent of the branch-circuit selection current For a wye-start, delta-run connected motor-compressor, the selection of branch-circuit conductors between the motor controller and the motor-compressor shall be permitted to be based on 72 percent of either the motor-compressor rated-load current or the branch-circuit selection current, whichever is greater. Informational Note: The multiplier of 72 percent is obtained by multiplying 58 percent by 1.25 because the individual motor circuit conductors of wye-start, delta-run connected motor-compressors carry 58 percent of the rated-load current. ENHANCED CONTENT Collapse See also 430.22(C) and its enhanced content for more information on wye-start, delta-run motors. 440.33 Motor-Compressor(s) With or Without Additional Motor Loads. Conductors supplying one or more motor-compressor(s) with or without an additional motor load(s) shall have an ampacity not less than the sum of each of the following: (1) The sum of the rated-load or branch-circuit selection current, whichever is greater, of all motor-compressor(s) The sum of the full-load current rating of all other motors 25 percent of the highest motor-compressor or motor full load current in the group Exception No. 1: Where the circuitry is interlocked so as to prevent the starting and running of a second motor-compressor or group of motor-compressors, the conductor size shall be determined from the largest motor-compressor or group of motor-compressors that is to be operated at a given time. Exception No. 2: The branch-circuit conductors for room air conditioners shall be in accordance with Part VII of Article 440. ENHANCED CONTENT Collapse Branch circuits for listed air-conditioning and refrigerating equipment that have a nameplate marked with the branch-circuit conductor size and branch-circuit short-circuit protective device size are not required to have the branch-circuit conductors sized in accordance with 440.33. The product standard includes the 25-percent increase for the largest motor or compressor in the group plus the other nonmotor or noncompressor load; therefore, the actual nameplate full-load amperes for the complete assembly can be used to size the branch-circuit conductors. 440.34 Combination Load. Conductors supplying a motor-compressor load(s) in addition to other load(s) shall have an ampacity sufficient for the other load(s) plus the required ampacity for the motor-compressor load(s).The motor compressor load(s) shall be determined in accordance with 440.32 or 440.33. The other load(s) shall be calculated from branch-circuit, feeder, and service load calculations. Exception: Where the circuitry is interlocked to prevent simultaneous operation of the motor-compressor(s) and all other loads connected, the conductor size shall be determined from the largest size required for the motor-compressor(s) and other loads to be operated at a given time. 440.35 Multimotor and Combination-Load Equipment. The ampacity of the conductors supplying multimotor and combination-load equipment shall not be less than the minimum circuit ampacity marked on the equipment in accordance with 440.4(B). Part V. Controllers for Motor-Compressors 440.41 Rating. (A) Motor-Compressor Controller. A motor-compressor controller shall have both a continuous-duty full-load current rating and a locked-rotor current rating not less than the nameplate rated-load current or branch-circuit selection current, whichever is greater, and locked-rotor current, respectively, of the compressor. In case the motor controller is rated in horsepower but is without one or both of the foregoing current ratings, equivalent currents shall be determined from the ratings as follows. Table 430.248, Table 430.249, and Table 430.250 shall be used to determine the equivalent full-load current rating. Table 430.251(A) and Table 430.251(B) shall be used to determine the equivalent locked-rotor current ratings. Controller Serving More Than One Load. A controller serving more than one motor-compressor or a motor-compressor a