1、UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULMAY 29, 20141UL 2748AOutline of Investigation for Arcing Fault Interrupting DevicesIssue Number: 2May 29, 2014Summary of TopicsThis Second issue of the Outline of Investigation is being published
2、 toinclude revisions to the requirements for the Internal Arcing Fault Testand for the Arcing Fault Interruption Test.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 Investiga
3、tion and all copyrights, ownerships, and rights regardingthose Outlines of Investigation shall remain the sole and exclusive property of UL.COPYRIGHT 2014 UNDERWRITERS LABORATORIES INC.UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULMAY 29, 20
4、14UL 2748A2No Text on This PageUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULCONTENTSINTRODUCTION1 Scope .42 Components 43 Units of Measurement .54 Undated References 55 Glossary .5CONSTRUCTION6 General 67 Creepage and Clearance Distance 68
5、Wiring .79 Operation 7RATINGS10 General .8MARKING11 General .8INSTRUCTIONS12 General .9PERFORMANCE13 General .914 Continuous Current Test 1015 Power-Frequency Withstand Voltage Tests 1016 Internal Arcing Fault Test .1017 Arcing Fault Interruption Test .11MAY 29, 2014 UL 2748A 3UL COPYRIGHTED MATERIA
6、L NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULINTRODUCTION1 Scope1.1 These requirements cover fast operating devices intended to interrupt currents associated with arcingfaults, having interrupting times faster than conventional overcurrent devices.1.2 These requ
7、irements cover open type devices that are intended to be installed within powerdistribution equipment.1.3 These requirements cover devices rated up to 38 kV ac maximum.1.4 This outline does not include the requirements for sensors intended to detect arcing faults, devicesintended to trigger the func
8、tioning of the arc interrupting device, or devices intended to quench arcingfaults by transferring the arc to a lower impedance path.1.5 This outline does not include requirements for integration and testing of arcing fault interruptingdevices within equipment it is intended to protect.2 Components2
9、.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 that:a) Involves a feature or characteristic not required in the application of the component in
10、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 Specific components are incomplete in construction features or restricted in performance capabilities.
11、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.MAY 29, 2014UL 2748A4UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSIO
12、N 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 to a code or standard appearing in the requirements of this outline shall beinterpreted as referring
13、 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 or other gas, includingdischarges across the surface of an insulating material.5.3 INTERRUPTING DEVI
14、CE A device that is used to interrupt an arcing fault.5.4 LOW VOLTAGE A voltage of 1000 V ac or less.5.5 MEDIUM VOLTAGE A voltage of greater than 1000 V ac, up to 38 kV ac.5.6 OPEN TYPE DEVICE A device not provided with an overall enclosure. An open type device isintended to be field installed withi
15、n an end-product equipment enclosure.5.7 POLLUTION DEGREE 2 MICROENVIRONMENT An area where normally only nonconductivepollution occurs, but where occasional, temporary conductivity may be expected. Typical constructionsthat reduce the possibilities of conductive pollution and condensation or high hu
16、midity are:a) Non-ventilated enclosures that are provided with continuous application of heat through theuse of heaters or through continuous energization of the device, with interruptions such thatcooling to the point of condensation does not occur; orb) The use of ventilated enclosures where all o
17、penings are provided with filters.5.8 RESETTABLE Capable of being returned to a closed position by pushing a button, moving ahandle, or similar means. Devices that cannot possibly be returned to a closed position withoutreplacing parts using special tools are not considered resettable.5.9 STANDARD P
18、ROTECTIVE DEVICE A fuse, circuit breaker, or other device that providesprotection against overcurrents and that complies with standards that define the operatingcharacteristics for the overcurrent device.MAY 29, 2014 UL 2748A 5UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIB
19、UTION WITHOUT PERMISSION FROM ULCONSTRUCTION6 General6.1 Other than as noted in 6.2, interrupting devices that are intended to directly replace standardprotective devices shall comply with the dimensional requirements for the standard protective device thatwill be replaced.6.2 Interrupting devices t
20、hat are intended to directly replace standard protective devices may have overalldimensions that differ from standard device that will be replaced, providing the dimensional changes donot affect the electrical connections or mounting of the device when the replacement is made.6.3 Interrupting device
21、s that are not direct replacements for standard protective devices shall not havedimensions that would allow the device to be inserted in place of a standard protective device.7 Creepage and Clearance Distance7.1 A device intended to replace a standard protective device shall comply with the creepag
22、e andclearance distance requirements of the standard used to investigate the standard protective device.7.2 Creepage and clearance distances within low voltage control circuits of interrupting devices shallcomply with the creepage and clearance distance requirements of the Standard for Industrial Co
23、ntrolEquipment, UL 508. Creepage and clearance distances between low voltage control circuits and mediumvoltage control circuits shall be no less than the creepage and clearance distances required from the lowvoltage circuit to grounded metal, and shall also be sufficient to meet the dielectric requ
24、irements specifiedin this outline for the maximum voltage rating of the device, with the control circuits grounded duringtesting.7.3 For printed wiring boards, the creepage and clearance distances shall comply with requirements ofthe Standard for Insulation Coordination Including Clearances and Cree
25、page Distances for ElectricalEquipment, UL 840. For the purpose of this investigation, interrupting devices shall be considered to belocated within circuits of overvoltage category 3. All interrupting devices are considered to be installed inpollution degree 3 environments, except for portions of th
26、e device located in a pollution degree 2microenvironment.7.4 Pollution Degree 2 shall be considered to exist on a printed-wiring board where a coating provides anuninterrupted covering of the conductive material for at least one of two conductive materials and coversthe entire space between the two
27、conductive materials for which the spacing is being evaluated.MAY 29, 2014UL 2748A6UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM UL8 Wiring8.1 Insulated conductors provided as part of an interrupting device shall be rated for the particularapp
28、lication and shall have an ampacity no less than the maximum current rating of the circuit to which theyare connected.8.2 Wiring shall be located or protected to prevent contact with any sharp edge or moving part that coulddamage the insulation.8.3 Insulated conductors shall be separated from wiring
29、 and uninsulated live parts connected to othercircuits, unless both circuits are provided with insulation rated for the highest voltage.9 Operation9.1 Interrupting devices with adjustable sensitivity shall comply with the requirements of this outline ofinvestigation over the entire range of possible
30、 settings.9.2 Interrupting devices that have provisions for disabling the arcing fault interrupting function shall haveprovisions for local and remote indication that the device has been disabled. Devices with provisions forintentionally delaying the time between detection of an arcing fault and ope
31、ration of the arcing faultinterrupting function shall have provisions for local and remote indication that operation of the interruptingfunction will be intentionally delayed.9.3 Interrupting devices that can be reset after an arcing fault has been interrupted shall be provided withvisual indication
32、 that the device has operated under an arcing fault condition and shall also haveprovisions for remote indication of arcing fault interruption function operation.9.4 Devices that cannot be reset after an arcing fault interruption, and must be replaced after interruption(such as a fusible element) ar
33、e not required to have such indication that the device has interrupted anarcing fault.9.5 Interrupting devices that are resettable, shall be marked in accordance with 11.5. Devices that cannotbe reset after an arcing fault interruption, and must be replaced after interruption (such as a fusibleeleme
34、nt) are not required to have such indication that the device has interrupted an arcing fault.MAY 29, 2014 UL 2748A 7UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULRATINGS10 General10.1 Interrupting devices shall have the following ratings:a)
35、Maximum rated voltage;b) Maximum arcing fault current;c) Minimum arcing fault current;d) Maximum number of operations (if the interrupting device is reusable);e) Power frequency (dielectric) withstand;f) Basic impulse withstand (medium voltage devices only);g) Rated control voltage;h) Continuous cur
36、rent 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.i) Devices intended to directly replace standard protective devices shall also have the ratingsrequired
37、 by the standard for the overcurrent device intended to be replaced.10.2 Interrupting devices shall be provided with time-current curves that provide the maximuminterruption times for all arcing fault currents between the minimum rated arcing fault current and themaximum rated arcing fault current.
38、These time-current curves shall be verified during the Arcing FaultInterruption Test, Section 17.MARKING11 General11.1 Devices shall be marked with the complete electrical ratings identified in 10.1.11.2 If fuseholders are provided in the control circuit, there shall be a marking near the fuseholder
39、specifying the voltage and current rating of replacement fuses. The marking shall also indicate themanufacturer and type designation of the fuse and may also include or equivalent.11.3 If a manufacturer produces or assembles interrupting devices at more than one factory, eachfinished section shall h
40、ave a distinctive marking that may be in code by which it may be identified asthe product of a particular factory.MAY 29, 2014UL 2748A8UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM UL11.4 Required markings shall be visible when the interruptin
41、g device is installed.11.5 Resettable interrupting devices shall be marked to indicate that the device is not to be returned toservice until after servicing has been completed. This marking shall include a reference to the appropriateinstruction manual, including the publication number and date (or
42、revision number) of the manual. Theinstruction manual shall provide detailed instructions on how to inspect the device for damage and how toservice the device such that it is restored to a fully functional condition in accordance with 12.3.11.6 Interrupting devices with adjustable settings shall be
43、provided with markings that clearly identify theposition of each setting.11.7 Interrupting devices with functions that can be disabled shall be provided with markings that clearlyindicate if the function is disabled or enabled.11.8 With respect to 11.6 and 11.7, if the settings or function status ar
44、e programmable, rather than set byphysical switches or dial positions, the interrupting device shall be provided with a display or otherindication of the settings and function status. The interrupting device shall also be marked with a referenceto the settings section of the appropriate instruction
45、manual, including the publication number and date (orrevision number) of the manual.INSTRUCTIONS12 General12.1 Interrupting devices shall be provided with instructions for proper installation, operation, andmaintenance. These instructions shall identify all accessories that have been investigated fo
46、r use with theinterrupting device, and shall provide details regarding the proper installation of these accessories.12.2 To provide for complete system performance testing, each device shall be provided with informationsheets describing system-testing instructions.12.3 Resettable devices shall be pr
47、ovided with instructions detailing the proper procedures for inspectionand restoration of the device to a fully functional condition.PERFORMANCE13 General13.1 Interrupting devices that are intended to directly replace standard protective devices shall complywith performance requirements for that sta
48、ndard protective device, including the required time-currentcharacteristics for overloads other than arcing faults.13.2 Interrupting devices shall comply with the requirements of Sections 14 17 with the interruptingdevice installed and connected in accordance with the manufacturers installation inst
49、ructions.13.3 Interrupting devices with adjustable settings shall be tested to demonstrate compliance with theperformance requirements over the range of possible settings, including minimum and maximum settings.MAY 29, 2014 UL 2748A 9UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM UL14 Continuous Current Test14.1 Devices intended to replace standard protective devices shall comply with the continuous current(temperature) test as required by the standard for the standard protective device.14.2 Low volt
