1、UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULDECEMBER 18, 20151UL 508IOutline of Investigation for Disconnect Switches Intended for Use inPhotovoltaic SystemsIssue Number: 2December 18, 2015Summary of TopicsThis second issue of the Outline
2、of Investigation for Disconnect SwitchesIntended for Use in Photovoltaic Systems, UL 508I, revises the scope toinclude electromechanical disconnect switches intended for disconnectingthe output of DC photovoltaic (PV) panels. The title of the outline wasrevised to reflect this change. Other revision
3、s include changing theambient temperature from 60C to 50C as well as adding tests forOvervoltage and Undervoltage, Alternate Overload and Minimum LoadOvervoltage.ULs Outlines of Investigation are copyrighted by UL. Neither a printed norelectronic copy of an Outline of Investigation should be altered
4、 in any way. All ofULs Outlines of Investigation and all copyrights, ownerships, and rights regardingthose Outlines of Investigation shall remain the sole and exclusive property of UL.COPYRIGHT 2015 UNDERWRITERS LABORATORIES INC.UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTR
5、IBUTION WITHOUT PERMISSION FROM ULDECEMBER 18, 2015UL 508I2No Text on This PageUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULCONTENTSINTRODUCTION1 Scope .42 Glossary .4CONSTRUCTION3 General 5PERFORMANCE REQUIREMENTS4 General 65 Temperature T
6、est .76 Overvoltage and Undervoltage Test .77 Overload .87.1 General .87.2 Alternate overload 87.3 Minimum load overvoltage test .88 Endurance Test .99 Dielectric Voltage Withstand 910 Short Circuit Withstand Test .1011 Voltage Withstand Test 10RATING12 General 11MARKING13 General 11DECEMBER 18, 201
7、5 UL 508I 3UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULINTRODUCTION1 Scope1.1 This outline of investigation covers open and enclosed manual and electromechanical disconnectswitches intended for disconnecting the output of DC photovoltaic (
8、PV) panels.1.2 Manual disconnect switches are intended for installation in accordance with Part III of Article 690 ofthe National Electrical Code, NFPA 70.1.3 Power operable (electromechanical) disconnect switches are intended for use as disconnectingpurposes supplementary to manual disconnecting me
9、ans that are required by Part III of Article 690 of theNational Electrical Code, NFPA 70.1.4 These requirements cover devices rated 1500 V or less and are intended for use in an ambienttemperature of -20C 50C unless specifically indicated for use in other conditions.1.5 These devices are intended fo
10、r use on the load side of PV branch protection devices.1.6 These requirements are intended to be used in conjunction with the Standard for Industrial ControlEquipment, UL 508, except as modified or supplemented by the following requirements.2 Glossary2.1 PV Photovoltaic.2.2 PV DISCONNECTAPVcontrolle
11、r that has been evaluated for use as a disconnect means in a PVsystem.2.3 PV MAXIMUM OPEN CIRCUIT VOLTAGE The maximum voltage the photovoltaic panel can deliverunder a no load condition. The open circuit voltage from a PV panel is typically 150 percent or more ofthe maximum operating power voltage.2
12、.4 PV MAXIMUM OPERATING POWER CURRENT The current associated with the point wheremaximum power is delivered from the photovoltaic panel.2.5 PV MAXIMUM OPERATING POWER VOLTAGE The voltage associated with the point wheremaximum power is delivered from the photovoltaic panel.2.6 PV MAXIMUM SHORT CIRCUI
13、T CURRENT The maximum current the photovoltaic panel iscapable of delivering under a continued short circuit condition. The short circuit voltage usually drops tonear zero under a short circuit condition.DECEMBER 18, 2015UL 508I4UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTR
14、IBUTION WITHOUT PERMISSION FROM ULCONSTRUCTION3 General3.1 The construction of these devices shall be in accordance with the requirements as specified forManual Motor Controllers intended for use as motor disconnecting means in the Standard for IndustrialControl Equipment, UL 508, Part III for Manua
15、l Motor Controllers or Part II for Magnetic Motor Controllers,as applicable, unless specified elsewhere in this outline.3.2 Spacing distance requirements shall be in accordance with the requirements outlined in the Standardfor Industrial Control Equipment, UL 508, Table 36.1, Column A or Table 36.1A
16、 as appropriate for thevoltage rating.3.3 Other than as noted in 3.4 and 3.5, as an alternative approach to the spacing requirements specifiedin 3.2, clearances and creepage distances may be evaluated in accordance with the requirements in theStandard for Insulation Coordination Including Clearance
17、and Creepage Distances for ElectricalEquipment, UL 840, as described in the Standard for Industrial Control Equipment, UL 508, Section 39.Clearances and creepages may be evaluated to Overvoltage Category IV and the switch markedaccording to 13.5.3.4 Clearances between an uninsulated live part and th
18、e walls of a metal enclosure, including fittings forconduit or armored cable, shall be in accordance with the requirements of 3.2. The clearances shall bedetermined by physical measurement.3.5 The clearance and creepage distance at field wiring terminals other than those which preclude thepossibilit
19、y of reduced spacing due to stray strands or improper wiring installation shall be in accordancewith the requirements of 3.2. The clearance and creepage distance at field wiring terminals which precludethe possibility of reduced spacing due to stray strands or improper wiring installation may be ina
20、ccordance with the requirements of 3.3.3.6 A PV disconnect device shall:a) Open all ungrounded conductors of the circuit to which it is connected, andb) Employ an operating handle that is accessible from outside of the enclosure or locatedbehind a hinged cover not requiring a tool for opening when t
21、he PV disconnect switch ismanually operated.3.7 Where the operating handle of a manually operated PV disconnect device is operated vertically ratherthan rotationally or horizontally, the up position of the handle shall be the on position.3.8 The operating means of a manually operated PV disconnect d
22、evice shall be provided with a methodof being locked in the off position.3.9 Wiring terminals shall be suitable for stranded copper wire in accordance with Section 25.5A,Evaluation of Pressure Wire Connectors, of the Standard for Industrial Control Equipment, UL 508.DECEMBER 18, 2015 UL 508I 5UL COP
23、YRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM UL3.10 A PV disconnect switch is also suitable for use with metric size, type PV wire within the AWG rangeof the wiring terminals in accordance with 3.9.3.11 Auxiliary contacts shall comply with Part X o
24、f the Standard for Industrial Control Equipment, UL 508,or with the Standard for Low-Voltage Switchgear and Controlgear Part 5-1: Control Circuit Devices andSwitching Elements Electromechanical Control Circuit Devices, UL 60947-5-1.PERFORMANCE REQUIREMENTS4 General4.1 A PV disconnect switch shall be
25、 subjected to the applicable tests described in this section. Tests thatare to be conducted in sequence are specified in Table 4.1. All testing except for short circuit testing shallbe conducted in a 50C ambient or at maximum rated ambient if higher than 50C. Short circuit testingcan be conducted at
26、 any convenient ambient between -20C and 50C.Table 4.1Sequence of tests for manual PV controllers used as disconnecting meansStandardreferenceSection TestSample Numbera12345cSequence Sequence Sequence Sequence Sequence5 Temperature 16Overvoltage andUndervoltage27.1 Overload 17.2AlternateOverload17.3
27、Minimum LoadOvervoltage28 Endurance 2 39 DielectricVoltageWithstand33 410 Short CircuitWithstand11b11 VoltageWithstand22aAll tests or any combination of test sequences are able to be conducted on a single sample when agreeable to thoseconcerned. More than one sample is able to be used when more than
28、 one rating is being tested. One sequence is not requiredto be completed as a prerequisite to the starting of another.bAn additional short circuit test per Section 10 is performed with the disconnect switch back-fed, that is, connected with theload side switch terminals to the supply and overcurrent
29、 protection and the leads connected to the line side terminals shortedtogether. Alternatively, a separate short circuit test sequence may be conducted on a separate sample with back-fedconnections. If the switch construction on both sides of the isolating contacts is identical (terminals, contacts,
30、internalconnections), a separate short circuit test with back-fed connections is not required.cTest sequence 5 may be used as an alternate or in addition to test sequence 2 for PV disconnect switches marked with thealternate ratings specified in 12.4.4.2 If agreeable to all concerned, the overload t
31、est may be conducted before the alternate overload teston the same sample for PV disconnect switches rated in accordance with both 12.1 and 12.4 as a meansto combine test sequences 2 and 5.DECEMBER 18, 2015UL 508I6UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT
32、 PERMISSION FROM UL5 Temperature Test5.1 A PV disconnect switch shall be subjected to the Temperature Test, Section 43, of the Standard forIndustrial Control Equipment, UL 508, while carrying a test current equal to the rated current.5.2 An electromagnetically operated PV disconnect switch shall be
33、tested with the rated contact currentflowing counter to the direction of flow through the energized coil as shown in Figure 5.1(B).Exception: An electromagnetically operated PV disconnect switch marked in accordance with 13.3 neednot be tested in accordance with this requirement.This is generated te
34、xt for figtxt.6 Overvoltage and Undervoltage Test6.1 An assembly using one or more electromagnetic switching components shall withstand 110 percentof the rated coil voltage without damage to the operating coil that prevents full closure of the switchedcontacts and shall operate at 80 percent of its
35、rated voltage when for use on direct current or 85 percentof its rated voltage when for use on alternating current.Figure 5.1Normal and Reverse Polarity TestingDECEMBER 18, 2015 UL 508I 7UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM UL6.2 An e
36、lectromagnet PV disconnect switch shall comply with the Overvoltage and Undervoltage Test,Section 45 of the Standard for Industrial Control Equipment, UL 508, except that the test shall beconducted with both normal and reverse direct current though the contact during the test as shown inFigure 5.1.7
37、 Overload7.1 General7.1.1 A PV disconnect switch shall comply with the Overload Test, Section 45 of the Standard forIndustrial Control Equipment, UL 508, for DC General Purpose, except the test is conducted at 200% ofrated current.7.1.2 The overload test on an electromagnetic disconnect switch shall
38、 be tested for half the total numberof required cycles in both normal and then for half the total number of required cycles in reverse polarityas shown in Figure 5.1 on the same sample. The cycle time may exceed more than 9 seconds off whenchanging from normal polarity to reverse polarity, but shall
39、 be as close to 9 seconds as practicable.7.2 Alternate overload7.2.1 For PV disconnect switches marked with the ratings specified in 12.4, the overload test, shall beconducted per 7.1 except under the following conditions:a) The load closed circuit voltage shall be at 75 to 80 percent of the maximum
40、 operatingvoltage that the PV disconnect switch is rated in accordance with 12.4,b) The load current shall be the median of the maximum operating current and the ratedmaximum short circuit current that the PV disconnect switch is rated in accordance with 12.4,c) The alternate overload shall be follo
41、wed by the Minimum Load Overvoltage Test, 7.3.7.3 Minimum load overvoltage test7.3.1 For PV disconnect switches marked with the ratings specified in 12.4, the overload test shall beconducted per 7.1 except under the following conditions following the alternate overload test:a) The load closed circui
42、t voltage shall be at 75 to 80 percent of the rated maximum opencircuit voltage that the PV disconnect switch is rated in accordance with 12.4, andb) The load current shall be the 75 percent of the rated maximum operating current that the PVdisconnect switch is rated in accordance with 12.4.DECEMBER
43、 18, 2015UL 508I8UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM UL8 Endurance Test8.1 A PV disconnect switch shall comply with the Endurance Test, Section 46 of the Standard forIndustrial Control Equipment, UL 508, for across-the-line motor sta
44、rting, except the endurance test cycles,cycle rate, and test parameters shall be as specified in Table 8.1.Table 8.1Endurance test cycles for PV controllers used as a disconnecting meansController rating inamperesaNumber of cycles ofoperation per minutebNumber of cycles of operationWith currentcWith
45、out current Total100 or less 6 6,000 4,000 10,000101 200 5 6,000 2,000 8,000201 400 4 1,000 5,000 6,000401 600 3 1,000 4,000 5,000aThe controller rating is the ampere rating marked on the product.bThe indicated number of cycles of operation per minute applies only to that part of the test performed
46、with current. When nocurrent is used, the manual PV disconnect switch is to be operated at any convenient speed.cTested at cycle rate indicated in Table 46.1 of the Standard for Industrial Control Equipment, UL 508, at rated current,resistive load.8.2 For PV disconnect switches marked with the ratin
47、gs specified in 12.4, the test voltage and currentshall be 100 to 110 percent of the maximum operating power voltage and current respectively that the PVdisconnect switch is rated in accordance with 12.4.8.3 The endurance test on an electromagnetic disconnect switch shall be tested for half the tota
48、l numberof required cycles in the normal polarity and then for half the total number of required cycles in reversepolarity as shown in Figure 5.1 on the same sample. The cycle time may exceed more than 9 seconds offwhen changing from normal polarity to reverse polarity, but shall be as close to 9 se
49、conds as practicable.Exception: An electromagnetic PV disconnect switch marked in accordance with 13.3 need not be testedwith both normal and reverse direct current though the contact during the test.9 Dielectric Voltage Withstand9.1 A PV disconnect switch shall comply with the Dielectric Voltage-Withstand Test, Section 49 of theStandard for Industrial Control Equipment, UL 508, and shall also withstand without dielectric breakdownthe test potential applied between line and load terminals of the PV disconnect switch with the disconnectcontacts open.D
