1、UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULNOVEMBER 3, 20151UL 2748Outline of Investigation for Arcing Fault Quenching EquipmentIssue Number 3November 3, 2015Summary of TopicsThis is the Third issue of the Outline of Investigation for Arc
2、ing FaultQuenching Equipment. These requirements cover devices intended toquench arcing faults by creating a lower impedance current path, locatedwithin a controlled compartment, to cause the arcing fault to transfer tothe new current path. The major revisions included in this issue include:1) Expla
3、nation of arc transfer times, including refinement of thetest methods to determine the actual arc transfer time(s),2) Clarify test methods for open type devices that are intended forinstallation in complete equipment, and3) Clarify that the internal arcing fault test and the arc transfer testcan be
4、combined into one test under certain conditions.ULs Outlines of Investigation are copyrighted by UL. Neither a printed norelectronic copy of an Outline of Investigation should be altered in any way. All ofULs Outlines of Investigation and all copyrights, ownerships, and rights regardingthose Outline
5、s of Investigation shall remain the sole and exclusive property of UL.COPYRIGHT 2015 UNDERWRITERS LABORATORIES INC.UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULNOVEMBER 3, 2015UL 27482No Text on This PageUL COPYRIGHTED MATERIAL NOT AUTHORIZ
6、ED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULCONTENTSINTRODUCTION1 Scope .42 Components 43 Units of Measurement .54 Undated References 55 Glossary .5CONSTRUCTION6 General 67 Enclosure 68 Primary or Power Carrying Circuits 69 Grounding 710 Control and Secondary Wiring .711 Cre
7、epage and Clearance Distance .712 Wiring 813 Operation .8RATINGS14 General .9MARKING15 General 10INSTRUCTIONS16 General 11PERFORMANCE17 General 1118 Continuous Current Test .1119 Power-Frequency Withstand Voltage Tests 1220 Maximum Arcing Fault Current Test .1221 Internal Arcing Fault Test 1322 Arc
8、Transfer Test .14NOVEMBER 3, 2015 UL 2748 3UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULINTRODUCTION1 Scope1.1 These requirements cover equipment intended to quench arcing faults by creating a lower impedancecurrent path, located within a c
9、ontrolled compartment, to cause the arcing fault to transfer to the newcurrent path.1.2 These requirements cover equipment that may either be completely enclosed units or intended to beinstalled within power distribution equipment.1.3 These requirements cover equipment rated up to 38 kV ac maximum.1
10、.4 This outline does not include the requirements for sensors intended to detect arcing fault, devicesintended to trigger the functioning of the arc quenching equipment, or devices that are intended tointerrupt arcing fault currents.1.5 This outline does not include all the requirements for integrat
11、ion and testing of arc quenchingequipment within equipment it is intended to protect.2 Components2.1 Except as indicated in 2.2, a component of a product covered by this outline shall comply with therequirements for that component.2.2 A component is not required to comply with a specific requirement
12、 that:a) Involves a feature or characteristic not required in the application of the component in theproduct covered by this outline; orb) Is superseded by a requirement in this outline.2.3 A component shall be used in accordance with its rating established for the intended conditions ofuse.2.4 Spec
13、ific components are incomplete in construction features or restricted in performance capabilities.Such components are intended for use only under limited conditions, such as certain temperatures notexceeding specified limits, and shall be used only under those specific conditions.NOVEMBER 3, 2015UL
14、27484UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM UL3 Units of Measurement3.1 Values stated without parentheses are the requirement. Values in parentheses are explanatory orapproximate information.4 Undated References4.1 Any undated reference
15、 to a code or standard appearing in the requirements of this outline shall beinterpreted as referring to the latest edition of that code or standard.5 Glossary5.1 For the purpose of this outline, the following definitions apply.5.2 ARCING FAULT A non-intentional discharge of electrical energy in air
16、 or other gas, includingdischarges across the surface of an insulating material.5.3 ARC TRANSFER TIME The interval between triggering of the arc quenching device and thequenching of the arc.5.4 CONTROLLED COMPARTMENT A portion of equipment, intended to enclose the new currentpath when an arcing faul
17、t is transferred. This compartment may be provided with openings or flaps forpressure relief.5.5 LOW VOLTAGE A voltage of 1000 V ac or less.5.6 MEDIUM VOLTAGE A voltage of greater than 1000 V ac, up to 38 kV ac.5.7 POLLUTION DEGREE 2 MICROENVIRONMENT An area where normally, only nonconductivepolluti
18、on occurs, but where occasional, temporary conductivity may be expected. Typical constructionsthat reduce the possibilities of conductive pollution and condensation or high humidity are;a) Un-ventilated enclosures that are provided with continuous application of heat through theuse of heaters or thr
19、ough continuous energization of the equipment, with interruptions such thatcooling to the point of condensation does not occur orb) The use of ventilated enclosures where all openings are provided with filters.5.8 QUENCHING DEVICE Equipment that is used to extinguish or redirect an arcing fault.NOVE
20、MBER 3, 2015 UL 2748 5UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULCONSTRUCTION6 General6.1 Where referenced in this outline of investigation, requirements contained in the Standard forMetal-Enclosed Low-Voltage Power Circuit Breaker Switch
21、gear, UL 1558, are applicable to low voltagequenching devices, and the requirements contained in the Standard for Metal-Enclosed Switchgear,ANSI/IEEE C37.20.3 are applicable to medium voltage quenching devices.7 Enclosure7.1 Other than as noted in 7.2, quenching devices shall comply with the require
22、ments of 7.3 7.6.7.2 Devices covered by this outline of investigation that are intended for installation completely within theenclosure of other equipment need not be provided with an enclosure.7.3 Low voltage devices provided with complete enclosures shall comply with the enclosure requirementsof t
23、he Standard for Metal-Enclosed Low-Voltage Power Circuit Breaker Switchgear, UL 1558, ANSIC37.20.1. Medium voltage devices provided with complete enclosures shall comply with the enclosurerequirements of the Standard for Metal-Enclosed Interrupter Switchgear, ANSI/IEEE C37.20.3.7.4 Where a portion o
24、f the quenching device is intended to fill or protrude through an opening, orotherwise form a portion of the enclosure of the overall equipment, it shall be investigated in accordancewith the enclosure requirements of the standard for the overall equipment.7.5 Devices described in 7.3 and 7.4 may be
25、 assigned one or more enclosure type designations inaccordance with 15.10. The devices shall comply with the requirements of the Standard for Enclosure forElectrical Equipment, Environmental Considerations, UL 50E for each assigned type designation wheninstalled.7.6 Gaskets relied upon to maintain t
26、he environmental rating of the equipment shall comply with thegasket requirements of the Standard for Enclosure for Electrical Equipment, EnvironmentalConsiderations, UL 50E.8 Primary or Power Carrying Circuits8.1 Low voltage equipment shall comply with Section 6 of the Standard for Metal-Enclosed L
27、ow-VoltagePower Circuit Breaker Switchgear, UL 1558.8.2 Medium voltage equipment shall comply with Section 7.1, Buses and primary connections, of theStandard for Metal-Enclosed Interrupter Switchgear, ANSI/IEEE C37.20.3.NOVEMBER 3, 2015UL 27486UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRO
28、DUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM UL9 Grounding9.1 There shall be provision for grounding all dead metal parts of the equipment. In addition, the followingparts shall be grounded:a) The metal case of a frame or instrument transformer;b) The metal case of an instrument, meter or relay; o
29、rc) The secondary circuit of a current or voltage transformer.9.2 The case of an instrument, relay, meter, or similar device, if mounted on a grounded metal surfaceand secured thereto by means of metal screws, is considered to be grounded.10 Control and Secondary Wiring10.1 An insulated conductor pr
30、ovided as part of a control circuit or secondary wiring shall be rated for theparticular application and shall have an ampacity not less than the continuous current rating of the circuitin which it is connected. Where loads are of an intermittent nature, such as in trip circuits, conductors shallbe
31、sized to provide their intended function with respect to voltage drop and mechanical strength.11 Creepage and Clearance Distance11.1 Section 12 of the Standard for Metal-Enclosed Low-Voltage Power Circuit Breaker Switchgear, UL1558 applies to the power circuits of low voltage quenching equipment, ot
32、her than as noted in 11.3.11.2 No minimum creepage or clearance distances are specified for medium voltage circuits in quenchingequipment, other than distances sufficient to meet the dielectric requirements specified in this outline forthe voltage rating of the equipment.11.3 No minimum creepage or
33、clearance distances are specified across the contacts of the quenchingmeans when these contacts are contained within a pollution degree 2 microenvironment, and thequenching equipment meets the dielectric test requirements of this outline with the quenching device inthe open position.11.4 Creepage an
34、d clearance distances within low voltage control circuits of quenching devices shallcomply with the creepage and clearance distance requirements of the Standard for Industrial ControlEquipment, UL 508. Creepage and clearance distances between low voltage control circuits and mediumvoltage control ci
35、rcuits shall be no smaller than the creepage and clearance distances required from thelow voltage circuit to grounded metal, and shall also be sufficient to meet the dielectric requirementsspecified in this outline for the maximum voltage rating of the equipment, with the control circuits groundeddu
36、ring testing.11.5 The pollution degree 2 microenvironment specified in 11.3 need not be maintained during or afterthe quenching of an arcing fault if servicing of the quenching means is required after an arcing fault event,and the quenching means is marked in accordance with 15.5.NOVEMBER 3, 2015 UL
37、 2748 7UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM UL11.6 For printed wiring boards, the creepage and clearance distances shall comply with requirements ofthe Standard for Insulation Coordination Including Clearance and Creepage Distances fo
38、r ElectricalEquipment, UL 840. For the purpose of this investigation, quenching devices shall be considered to belocated within circuits of overvoltage category 3. All quenching devices are considered to be installed inpollution degree 3 environments, except for portions of the device located in a p
39、ollution degree 2microenvironment.11.7 Pollution Degree 2 shall be considered to exist on a printed-wiring board where a coating providesan uninterrupted covering of the conductive material for at least one of two conductive materials andcovers the entire space between the two conductive materials f
40、or which the spacing is being evaluated.12 Wiring12.1 Insulated conductors provided as part of a quenching device shall be rated for the particularapplication and shall have an ampacity no less than the maximum current rating of the circuit to which theyare connected.12.2 Wiring shall be located or
41、protected to prevent contact with any sharp edge or moving part that coulddamage the insulation.12.3 Insulated conductors shall be separated from wiring and uninsulated live parts connected to othercircuits, unless both circuits are provided with insulation rated for the highest voltage.13 Operation
42、13.1 Quenching devices with adjustable sensitivity shall comply with the requirements of this outline ofinvestigation over the entire range of possible settings.13.2 Quenching devices that have provisions for disabling the quenching function shall have provisionsfor local and remote indication that
43、the device has been disabled. Devices with provisions for intentionallydelaying the time between detection of an arcing fault and operation of the quenching function shall haveprovisions for local and remote indication that operation of the quenching function will be intentionallydelayed.13.3 Quench
44、ing devices shall be provided with visual indication that the quenching function has operated.Devices shall also have provisions for remote indication of quenching function operation.13.4 Quenching devices that are intended to be replaced or serviced after every quenching functionoperation shall hav
45、e provisions for interlocking such that the circuit protected by the quenching devicecannot be reenergized until the quenching device has been replaced or serviced. These devices shall bemarked in accordance with 15.5.NOVEMBER 3, 2015UL 27488UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODU
46、CTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULRATINGS14 General14.1 Quenching devices shall have the following ratingsa) Maximum rated voltage;b) Maximum arcing fault current;c) Minimum arcing fault current (if a minimum current is required for proper operation);d) Short time (fault current) withst
47、and duration;e) Maximum number of operations (if the quenching device is reusable);f) Dielectric withstand voltage;g) Basic impulse withstand (medium voltage equipment only);h) Rated control voltage;i) Enclosure type rating(s), where applicable, unless intended for installation completely withinmeta
48、l-enclosed switchgear or similar equipment.j) Continuous current rating, when the device is part of the continuous current path duringnormal operation. Devices that carry current only while performing the quenching function haveno continuous current rating.14.2 Arc transfer times for quenching devic
49、es shall be provided by the manufacturer in accordance withone of the following:a) Quenching devices that require a minimum arcing fault current for proper operation shall beprovided with time-current curves that provide the maximum transfer times for all arcing faultcurrents between the minimum rated arcing fault current and the maximum rated arcing faultcurrent. These time-current curves shall be verified during the Arc Transfer Test, Section 22.b) Quenching devices that do not require a minimum arcing fault current for proper operationshall have a maximum rated
