1、UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULDECEMBER 8, 20141UL 2877Outline of Investigation for Power Supplies, Medium VoltageIssue Number: 1December 8, 2014Summary of TopicsThis first issue of the Outline of Investigation for Power Suppl
2、ies, MediumVoltage, UL 2877, covers requirements for power supplies with inputvoltage ratings greater than 1000 V, to 15 kV.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 Inv
3、estigation 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 ULDECE
4、MBER 8, 2014UL 28772No Text on This PageUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULCONTENTSINTRODUCTION1 Scope .52 Glossary .53 Components 64 Units of Measurement .65 Undated References 6CONSTRUCTION6 General 67 Enclosures .78 Grounding a
5、nd Bonding 109 Protective Devices .1210 Isolating Means .1211 Interlocking 1211.1 Isolating means interlocks .1211.2 Drawout element interlocks 1311.3 Door interlocks .1412 Automatic Restarting 1413 Wiring and Connections .1514 Insulating Materials .1815 Field Installed Accessories .1916 Spacings 19
6、16.1 General .1916.2 Circuits of 1000 V or less to ground 2116.3 Spacings to SELV circuits .2216.4 Spacings for printed wiring boards in accordance with the Standard for InsulationCoordination Including Clearances and Creepage Distances for Electrical Equipment, UL840 .2217 Current Carrying Parts 24
7、18 SELV Circuits 2418.1 General requirements .2418.2 Voltages under normal conditions 2418.3 Voltages under single fault conditions .2518.4 Separation from hazardous voltages 2519 Modular Constructions .25PERFORMANCE20 General 2621 Temperature Test .2721.1 General .2721.2 Test conditions .2922 Overl
8、oad Test 2923 Overvoltage Test .3024 Mechanical Tests .3025 Output Short Circuit Test 3126 Dielectric Voltage-Withstand Tests (Power Frequency and Impulse) 3326.1 Power-frequency voltage withstand test .33DECEMBER 8, 2014 UL 2877 3UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDIS
9、TRIBUTION WITHOUT PERMISSION FROM UL26.2 Impulse withstand tests .3427 Switching Capacity Test - Isolating Means .3627.1 Non-interlocked isolating means 3627.2 Interlocked isolating means 3728 Mechanical Tests of Viewing Panes .3729 Rod Entry Test .3730 Enclosure Ground Integrity Test 3831 Driven Ra
10、in Test 3832 Shutter Integrity Test 3833 Inoperative Blower Motor Test 3834 Clogged Filter Test 3835 Breakdown of Components Test .3836 Verification of SELV Circuits Test .40RATING37 General 40MARKING38 General 4139 General Markings for Power Supplies .4140 Conditional Markings 4241 Additional Equip
11、ment Information .44DECEMBER 8, 2014UL 28774UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULINTRODUCTION1 Scope1.1 These requirements cover power supplies having ac input voltage ratings above 1000 V, up to 15 kV,and ac or dc output voltage ra
12、tings up to 15 kV, including power supplies that provide one or more outputsclassified as safety extra low voltage (SELV).1.2 These requirements cover equipment intended for use in ordinary locations in accordance with theNational Electrical Code.1.3 These requirements also cover open type, or parti
13、ally enclosed power supplies intended to beinstalled in equipment where the overall assembly is investigated using this outline of investigation, oranother applicable standard for medium voltage equipment.2 Glossary2.1 The definitions in UL 347 are applicable. Where definitions in this outline confl
14、ict with definitions inUL 347, the definitions in this outline take precedence.2.2 SELV CIRCUIT A secondary circuit with voltages that do not exceed a safe value under normaloperating conditions and single fault conditions.NOTE: The voltage limits for SELV circuits are specified in 18.1.2.3 BASIC IN
15、SULATION Insulation to provide protection against electric shock.2.4 DOUBLE INSULATION Insulation consisting of basic insulation, plus supplementary insulation.2.5 MODULAR CONSTRUCTION POWER SUPPLIES Power supplies using multiple modules, eachwith low voltage input and output voltage ratings. Refer
16、to 19.1.2.6 REINFORCED INSULATION A single insulation that provides equivalent protection against electricshock as double insulation.2.7 STANDBY CURRENT The current that flows in the input circuit of a power supply when the powersupply is connected to a source of rated voltage, but is not delivering
17、 load current.2.8 SUPPLEMENTARY INSULATION Insulation that is independent of, and in addition to, basicinsulation, that provides the same level of insulation as the basic insulation, should the basic insulationfail.DECEMBER 8, 2014 UL 2877 5UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUC
18、TION ORDISTRIBUTION WITHOUT PERMISSION FROM UL3 Components3.1 A component of a product covered by this Outline shall comply with the requirements for thatcomponent and shall be used in accordance with its recognized rating and other limitations of use. SeeAppendix A for a list of standards covering
19、components used in the products covered by this outline. Acomponent 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 theproduct covered by this outline, orb) Is superseded by a requirement in this o
20、utline.3.2 Components that provide isolation between medium voltage circuits and low voltage circuits (such astransformers, optical isolators, and the like) shall be provided with sufficient insulation to withstand therated power frequency dielectric voltage and rated impulse voltage between the cir
21、cuits.3.3 Components that provide isolation between medium voltage circuits and SELV circuits shall beprovided with double or reinforced insulation, and the insulation shall be sufficient to withstand 160% ofthe rated power frequency dielectric voltage and 160% of the rated impulse voltage between t
22、he circuits.4 Units of Measurement4.1 Values stated without parentheses are the requirement. Values in parentheses are explanatory orapproximate information.5 Undated References5.1 Any undated reference to a code or standard appearing in the requirements of this outline shall beinterpreted as referr
23、ing to the latest edition of that code or standard.CONSTRUCTION6 General6.1 Equipment as covered by this outline shall:a) Be so constructed as to provide for compliance with the rules for installation and use of suchequipment as given in the National Electrical Code, ANSI/NFPA 70; andb) Employ mater
24、ials that are acceptable for the particular use.DECEMBER 8, 2014UL 28776UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM UL7 Enclosures7.1 This section does not apply to open type power supplies. For partially enclosed power supplies, thissection
25、 applies to any portion of the power supply that may form part of the overall assembly enclosurewhen assembled into other equipment.7.2 In addition to the following, the enclosure requirements of UL 50 and UL 50E apply. If there is aconflict between the requirements in this outline and UL 50 or UL 5
26、0E, the requirements in this outlineapply.7.3 Enclosures shall be metallic, and built to the requirements of UL 50 and UL 50E, except thatenclosure thickness shall be in accordance with 7.15. External parts of the power supply may be ofinsulating material, provided that all medium-voltage parts are
27、completely enclosed by grounded metallicpartitions having material thickness equivalent to that required for the enclosure. This does not precludethe use of inspection windows or ventilation openings as detailed in 7.4 and 7.5, respectively.7.4 Inspection windows may be provided and form part of the
28、 enclosure when all of the followingconditions are met:a) The window shall an infrared viewport that complies with UL 50V, or shall be of clear safety-type glass, wire-reinforced glass, or another clear material found suitable with respect toflammability and UV resistance in accordance with UL 746C;
29、b) The window shall be secured in such a manner that it cannot be removed without tools; andc) The window shall meet the requirements of the impact and pressure tests for viewing panesspecified in Section 28.7.5 Ventilation openings may be provided when they comply with the following:a) Ventilation
30、openings, including perforations, louvers, and openings protected by means ofwire screening, expanded metal, or a perforated cover, shall comply with the rod entry testspecified in Section 29.b) Barriers shall be provided behind all ventilating openings into medium-voltage compartments.The barrier s
31、hall be effectively secured in place and shall prevent drawing a straight line fromany point outside the enclosure to any medium voltage live part, including insulated parts.c) The diameter of the wires of a screen covering a ventilation opening shall be not less than1.3 mm (0.050 in) if the screen
32、openings are 320 mm2(0.497 in2) or less in area, and shall benot less than 2.06 mm (0.081 in) for larger screen openings.d) Perforated sheet steel and sheet steel employed for expanded metal mesh shall be not lessthan 1.07 mm (0.042 in) thick for mesh openings or perforations 320 mm2(0.497 in2) or l
33、ess inarea, and shall be not less than 2.03 mm (0.080 in) thick for larger openings.DECEMBER 8, 2014 UL 2877 7UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM UL7.6 Enclosures with forced ventilation shall comply with 7.7 and 7.8.7.7 When ventila
34、tion is accomplished by one or more blowers within the enclosure that provide a positiveintake and exhaust, the ventilation openings shall be located such that the exhaust air is not directedtoward the area occupied by the equipment operator.7.8 When equipment incorporates a blower motor, it shall c
35、omply with the Inoperative Blower Motor Test,Section 33.7.9 When a power supply is provided with filters for ventilation openings, the construction shall complywith the Clogged Filter Test, Section 34, and with (a) or (b) below:a) The filters shall be located in a medium voltage compartment so that
36、the filters cannot bereplaced without opening a door or cover to the compartment. The door of the compartmentshall be interlocked in accordance with Section 11, Interlocking.b) The filters shall be located outside of a medium voltage compartment, so that the filters maybe replaced without opening th
37、e medium voltage compartment. During any period of filterreplacement, including with a filter access cover open and no filter installed, the constructionshall comply with 7.5.7.10 Enclosures shall comply with the rod entry test of Section 29.7.11 Doors and covers shall be provided with means such as
38、 latches, locks, interlocks, bolts or screwsfor firmly securing them in place. Covers of compartments containing medium-voltage components shallbe bolted closed.7.12 If uninsulated live parts are exposed by the opening of a door or cover, means shall be provided tosecure it in the closed position. T
39、his securement means shall require the use of a tool other than a keyto open the door or cover. If parts operating above 1000 V are exposed by the opening of a cover or door,a warning marking shall be provided in accordance 40.1(a).7.13 Parts mounted on the interior of a door shall be effectively gu
40、arded or enclosed to provide protectionagainst unintentional contact when the door is opened for maintenance of the equipment.7.14 The following requirements shall apply to power supplies intended for outdoor use:a) External hinged doors or covers shall be provided with stops to hold them in the ope
41、nposition;b) Enclosures shall be subjected to the driven rain test described in Section 31 in addition toany test requirements for the Type designation marked on the enclosure in accordance with UL50E;c) Enclosures shall have provisions for locking to prevent access to medium-voltagecompartments; an
42、dd) Consideration should be given to prevention of condensation and entry of snakes, rodents,etc.DECEMBER 8, 2014UL 28778UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM UL7.15 The thickness of a sheet-metal enclosure at points to which a wiring
43、system is to be connected shallbe not less than 0.8 mm thick for uncoated steel, 0.9 mm thick for zinc-coated steel, and 1.2 mm thick fornon-ferrous metal. Enclosure thickness at points other than where a wiring system is to be connected shallbe not less than that specified in Table 7.1 or Table 7.2
44、. With reference to Table 7.1 and Table 7.2, asupporting frame is a structure of angle or channel or folded section of sheet metal, which is attached toand has the same outside dimensions as the enclosure surface, and which has torsional rigidity to resistthe bending moments that are applied by the
45、enclosure surface when it is deflected. A structure which isas rigid as one built with a frame of angles or channels has equivalent reinforcing. Constructions withoutsupporting frame include:a) A single sheet with single formed flanges formed edges;b) A single sheet which is corrugated or ribbed;c)
46、An enclosure surface loosely attached to a frame, for example, with spring clips; andd) An enclosure surface having an unsupported edge.Table 7.1Thickness of sheet metal for enclosures: carbon steel or stainless steelWithout supporting frameaWith supporting frameaMinimum thicknessMaximum width Maxim
47、um length Maximum width Maximum lengthmmbmmcmmcmmcmm100 Not limited 160 Not limited 0.6d120 150 170 210150 Not limited 240 Not limited 0.75d180 220 250 320200 Not limited 310 Not limited 0.9230 290 330 410320 Not limited 500 Not limited 1.2350 460 530 640460 Not limited 690 Not limited 1.4510 640 74
48、0 910560 Not limited 840 Not limited 1.5640 790 890 1090640 Not limited 990 Not limited 1.8740 910 1040 1300840 Not limited 1300 Not limited 2.0970 1200 1370 16801070 Not limited 1630 Not limited 2.51200 1500 1730 21301320 Not limited 2030 Not limited 2.81520 1880 2130 26201600 Not limited 2460 Not
49、limited 3,01850 2290 2620 3230aSee 7.15.bThe width is the smaller dimension of a rectangular piece of sheet metal which is part of an enclosure. Adjacent surfaces ofan enclosure are able to have supports in common and be made of a single sheet.c“Not limited” applies only when the edge of the surface is flanged at least 12.7 mm or fastened to adjacent surfaces notnormally removed in use.dSheet steel for an enclosure intended for outdoor use shall be not less than 0.86 mm thick.DECEMBER 8, 2014 UL 2877 9UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION
