6.0 INTERPRETATIONS AND SUPPLEMENTAL INFORMATION
BC § 6.0
6.1 Substitutions and Additions to UL 465, Standard for Safety, Central Cooling Air Conditioners. 6.1.1 To Section 1.1 add: Liquid chillers as described in this procedure are normally installed in systems classified as "Indirect Systems" as described in Section 4.4 of ANSI B9.1, Safety Code for Mechanical Refrigeration, where there is no direct interface between the refrigerant and the air serving the conditioned space. 6.1.2 In Section 1.3 change maximum voltage to 15,000 volts. 6.1.3 To Section 3.2 add: Where the compressor motor controller and overload protective device are not furnished by the manufacturer of the chiller, the manufacturer shall provide a specification for these components for the customer. The specification shall include information as to the required controller rating, sequencing of start, overload protection trip current and connections to the chiller control system. If a current transformer to provide a signal input circuit to the chiller control system is to be included, the specification is to include the requirements for the current transformer and its shunting device, if any. 6.1.4 To Section 8.19 thru 8.26 add: If the field-wiring enclosure of the motor or that portion of the wiring enclosure to which a field-wiring system (conduit) is to be connected can be readily removed and replaced in the field, an opening or knockout for connection of a wiring system to the motor is not required to be provided. The surface of the enclosure to which the field-wiring system is to be connected shall be of adequate size to accommodate the number and size of conduits which may be required for the installation. 6.1.5 To Section 10.24 add: Soldering lugs or pressure terminal connectors are not required to be provided by the manufacturer for connection of the field wiring to hermetic motor power supply terminals. Threaded studs of adequate size and length are to be used. Nuts for the studs shall be provided to adequately secure at least one terminal connector to each threaded stud. 6.1.6 To Section 11 add: Wiring to hermetic motors shall be with copper conductors only unless it can be determined that galvanic corrosion due to condensation at the terminals will not occur. 6.1.7 To Section 12 add: A. A Signal input circuit derived from a current transformer sensing the motor current and located in the (remote) motor controller is considered to be a National Electrical Code Class 1 circuit. It shall be segregated or separate from other circuits. B. Unless provided with insulation rated for the highest voltage involved, terminals for temperature sensors, when furnished on motors, shall be located in a separate enclosure or shall be separated by substantial barriers from the space provided for field wiring to the power supply connections on the motor. C. Factory wiring to such sensing devices shall be protected from damage during installation of field wiring to the motor. 6.1.8 To Table 13.1 add the conductor sizes for larger current ratings from Table 250–95 of National Electric Code NFPA No. 70. 6.1.9 To Section 16 add: A. Insulating materials used inside hermetic motors shall be compatible with the refrigerants and oil used. They shall also be compatible with each other and with other materials used within the motor. B. Compliance with paragraph (A) is to be judged in the same manner as for materials used in hermetic motor-compressors as judged under the Standard for Sealed (Hermetic Type) Motor-Compressors, UL 984. 6.1.10 To Section 23 add: A. For hermetic motors rated 600 volts or less, the spacings inside the motor shall conform with the requirements in the Standard for Sealed (Hermetic Type) Motor-Compressors, UL 984. B. For hermetic motors rated more than 600 volts, the spacings shall conform with paragraphs (C) thru (E) inside and outside the enclosure. C. Except as indicated in paragraph (E), the spacing between uninsulated live parts of different polarity shall not be less than the value indicated in Table 6–1. TABLE 6–1Minimum Spacings Between Uninsulated Live Parts of Different Polarity Rating Volts Through Space Inches Oversurface Inches Rating Volts Through Space Inches Oversurface Inches 601– 1,000 3/8 1/2 1,001– 2,000 3/4 1 3/8 2,001– 3,000 1 1/2 2 1/2 3,001– 5,000 3 1/44 1/2 5,001– 7,500 4 1/25 1/2 7,501–12,500 5 1/47 1/2 12,501–15,000 6 1/28 1/2 D. Except as indicated in paragraph (E), the spacing between uninsulated live parts and dead-metal parts including the enclosure shall not be less than the value indicated in Table 6–2. TABLE 6–2Minimum Spacings Between UninsulatedLive Parts and Dead-Metal Parts Rating Volts Through Space Inches Oversurface Inches Rating Volts Through Space Inches Oversurface Inches 601– 1,000 3/8 1/2 1,001– 2,000 3/41 3/8 2,001– 3,000 1 1/22 1/2 3,001– 5,000 2 1/23 1/2 5,001– 7,500 3 1/23 1/2 7,501–12,500 4 3/85 1/212,501–15,000 5 1/25 3/4 E. Linings or barriers of suitable insulating materials may be employed where the spacings are less than the values specified in Tables 6–1 and 6–2 provided that the linings or barriers are securely fastened in place. F. Spacings inside hermetic type oil pump assemblies shall comply with the spacing requirements for inside hermetic motors. See paragraph (A). Spacings in non-hermetic motors shall comply with the Safety Standard for Electric Motors, NEMA Publication MG–2. G. A signal input circuit at a low level of voltage or current to the chiller control system which is derived from a current transformer sensing the motor current and located in the (remote) motor controller is not considered to be a low-voltage circuit. The spacings on the basis of the maximum available voltage or current at the component from the signal circuit with the motor operating at rated load current assuming this is a high-voltage circuit, and as described in paragraph (I). Consideration shall also be given to the voltage and current available during starting and stalled rotor conditions. H. The terms "low-voltage circuit" and "high-voltage circuit" are defined in UL 465, paragraph 2.2. I. Provision shall be made for limiting the potential (voltage) in the chiller control assembly resulting from an open secondary circuit of a remote current transformer, such as described in paragraph (G) to a potential (voltage) for which the chiller control components in this circuit are acceptable. J. The open secondary circuit may result from an open remote shunt resistor or from a disconnected or broken conductor at the connection to the chiller control circuit. 6.1.11 For Section 27.5 substitute 8.3.1 of ANSI B9.1 Safety Code for Mechanical Refrigeration. 6.1.12 For Section 27.10 substitute the following: The dial of a pressure gauge permanently connected to the high side of a refrigeration system shall be graduated up to not less than 1.2 times the design pressure of the high side of the system. 6.1.13 In Section 28.5 change maximum setting of pressure-limiting device to 90% of the design pressure of the high side of the refrigeration system for positive displacement compressors and 100% of the design pressure of the high side of the refrigeration system for non-positive displacement compressors. 6.1.14 For Section 29 substitute Section 10, Pressure Relief Protection, of ANSI B9.1 Safety Code for Mechanical Refrigeration. 6.1.15 For Section 34.1 substitute: A. During the Input Test the chiller shall be run at design operating conditions as stipulated on the equipment submittal drawings. B. During the Temperature and Pressure Test, the chiller shall be run at the design chilled water leaving temperature and flow rate conditions as stipulated on the equipment submittal drawings and the chiller loaded to the rated current of the motor by adjusting the condenser water or air flow rate and/or temperature. If a variable speed drive is furnished, the compressor is to run at its design operating speed. 6.1.16 To Section 35 add: An input test is not required if the chiller is provided with a current-limiting control for the motor or if the compressor is driven by a prime mover other than an electric motor. 6.1.17 To Section 36.1 and Table 36.1 add: The temperature on the winding of an hermetic motor shall not exceed a value appropriate for the insulation system or for the refrigerant and oil employed. 6.1.18 To Section 39 add: The dielectric withstand test on the main motor may be conducted by the Laboratory at the motor manufacturer's plant if an open drive motor, or the chiller manufacturer's plant if an hermetic motor after final assembly of the motor in its enclosure. During the test low voltage circuits, motor sensor elements, and signal input circuits are to be connected to the enclosure. 6.1.19 To Section 39.1 add: C. Test potential may be 20% higher for a period of one second when the test is performed in the manufacturer's plant. D. Test potential shall be 85% of that in A, B, or C when the test is performed in the field. 6.1.20 For Section 51.3 substitute: Parts exposed to high side refrigerant pressure shall withstand, without failure, a pressure equal to five times the factory test pressure for the high side of the refrigeration system. 6.1.21 For Section 51.5 substitute: A refrigerant-containing component having a marked design pressure shall withstand, without failure, a pressure equal to three times the working pressure. 6.1.22 For Section 51.6 substitute: High side parts of a liquid chiller provided with a pressure limiting device required for compliance with Section 28.1 shall withstand, without failure, a pressure equal to three times the maximum setting to which the pressure limiting device may be readily adjusted by the adjusting means provided for centrifugal and screw equipment and five and one-half times for reciprocating equipment. 6.1.23 For Section 51.13 substitute: Parts exposed to low side refrigerant pressure shall withstand, without failure, a pressure equal to three times the design pressure of the low side of the refrigeration system. 6.1.24 To Section 51.15 add: If results of tests of samples of a refrigerant containing part are not readily available from the manufacturer, the Laboratory shall be responsible for obtaining samples and for testing. Samples subjected to such strength tests may not be used on the equipment being investigated. 6.1.25 For Section 55 substitute the following: Every liquid chilling unit, whether assembled in the manufacturer's plant or erected on the premises, shall be subjected to the Field Test stipulated in Section 12 of ANSI B9.1 Safety Code for Mechanical Refrigeration. 6.2 Deletions. 6.2.1 The following sections of UL 465 Standard for Safety, Central Air Conditioners are not applicable to liquid chilling units described in this procedure since such chillers do not include components located in the air stream serving the conditioned space: 9, 21.2, 21.3, 24.3, 27.8, 32.1, 33, 36.10, 42 and 55.3. 6.2.2 The provisions of Section 5 of NEMA Standards Publication Nos. 21 and 22 covering turbine sound pressure levels are not included as a requirement in this procedure. 6.2.3 The provisions of Section 91 of ANSI B176.1 (NFPA No. 37) covering fire extinguishers are not included as a requirement in this procedure.
