UL SUBJECT 3004-2018 Outline of Investigation for Medium Voltage Junction Boxes (Issue 1).pdf

1、UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULAUGUST 1, 20181UL 3004Outline of Investigation for Medium Voltage Junction BoxesIssue Number: 1August 1, 2018Summary of TopicsThis First Issue of UL 3004, the Outline of Investigation for MediumV

2、oltage Junction Boxes, covers requirements for junction boxes used fortermination of medium voltage conductors.ULs Outlines of Investigation are copyrighted by UL LLC. Neither a printed norelectronic copy of an Outline of Investigation should be altered in any way. All ofULs Outlines of Investigatio

3、n and all copyrights, ownerships, and rights regardingthose Outlines of Investigation shall remain the sole and exclusive property of ULLLC.COPYRIGHT 2018 UL LLCUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULAUGUST 1, 2018UL 30042No Text on T

4、his PageUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULCONTENTSINTRODUCTION1 Scope .52 Components 53 Units of Measurement .64 Undated References 65 Glossary .65.1 General .65.2 Equipment ratings 7CONSTRUCTION6 Enclosure 76.1 General .76.2 Ext

5、erior doors, covers, and similar parts of enclosures 86.3 Inspection windows .86.4 Enclosure category .97 Wire Bending Space 97.1 Wire-bending space for field-installed conductors .98 Wiring Terminals .108.1 Connection of current-carrying conductors 108.2 Connection of conductor shields .109 Bus Bar

6、s 1010 Insulating Materials .1111 Provisions for Bonding and Grounding 1111.1 Grounding of exposed metal parts 1111.2 Provision for ground termination 1112 Spacings 13PERFORMANCE13 Low Voltage Auxiliary and Control Equipment 13PERFORMANCE14 Short-Time Withstand Current and Peak Withstand Current Tes

7、ts 1414.1 General .1414.2 Short-time withstand current test .1414.3 Short-time withstand current test on ground bus .1614.4 Short-time withstand current test on neutral bus 1714.5 Peak withstand current test 1815 Dielectric Tests .1915.1 General .1915.2 Impulse withstand tests .2015.3 Power-frequenc

8、y voltage withstand test .2215.4 Test for bus bar insulation .2316 Driven Rain Test 2316.1 General .2316.2 Test method .2316.3 Evaluation .24AUGUST 1, 2018 UL 3004 3UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM UL17 Mechanical Tests of Viewing

9、 Panes .2417.1 General .2417.2 Pressure test 2417.3 Impact test 25RATINGS18 General 25MARKINGS AND INSTRUCTIONS19 General 2520 External Conditions .2621 Terminals 2622 Special Openings .27APPENDIX AA.1 Standards for Components or Standards Referenced A1AUGUST 1, 2018UL 30044UL COPYRIGHTED MATERIAL N

10、OT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULINTRODUCTION1 Scope1.1 These requirements cover medium voltage junction boxes. Medium voltage junction boxes are ratedover 1000 V ac, up to 38,000 V ac, contain insulators, and bus bars or other means, such as separablei

11、nsulated connector systems, to connect medium voltage conductors. These boxes may also include otherassociated junction boxes such as mechanical supports, ground bus for cable shields, for the purpose ofconnecting medium voltage conductors. These junction boxes are intended to be used in accordance

12、withthe National Electrical Code, NFPA 70.1.2 The conductors may be routed through knockouts or openings in the enclosure for cable, conduit, orelectrical metallic tubing. These junction boxes may also have special openings to match with similaropenings in other equipment such as medium voltage moto

13、r controllers, switchgear, switch or circuitbreaker enclosures, wireways, and the like.1.3 Medium voltage junction boxes are not intended to be used as pull boxes, where cables pass throughthe enclosure without terminating within the enclosure.2 Components2.1 Except as indicated in 2.2, a component

14、of a product covered by this outline shall comply with therequirements for that component. See Appendix A for a list of standards covering components generallyused in the products covered by this outline.2.2 A component is not required to comply with a specific requirement that:a) Involves a feature

15、 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 Specific components are incompl

16、ete 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.AUGUST 1, 2018 UL 3004 5UL COPYRIGHTED MATERIA

17、L 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 to a code or standard appe

18、aring in the requirements of this outline shall beinterpreted as referring to the latest edition of that code or standard.5 GlossaryFor the purpose of this outline, the following definitions apply.5.1 General5.1.1 CLEARANCE The distance between two conductive parts along a string stretched the short

19、estway between these conductive parts.5.1.2 COVER An unhinged portion of an enclosure that covers an opening.5.1.3 CREEPAGE DISTANCE The shortest distance along the surface of an insulating materialbetween two conductive parts.5.1.4 DISRUPTIVE DISCHARGE The phenomena associated with the failure of i

20、nsulation underelectric stress; these include a collapse of voltage and the passage of current. The term applies toelectrical breakdown in solid, liquid, and gaseous dielectrics, and combinations of these dielectrics.5.1.5 DOOR A hinged portion of an enclosure that covers an opening.5.1.6 ENCLOSURE

21、A surrounding case constructed to provide a degree of protection to personnelagainst incidental contact with the enclosed equipment and to provide a degree of protection to theenclosed equipment against specified environmental conditions.5.1.7 PROSPECTIVE CURRENT The current that would flow in the c

22、ircuit if each pole of the circuitwere replaced by a conductor of negligible impedance.NOTE: For testing, the prospective current is determined by calibrating the test circuit with a short circuit placed directly across thetest station terminals. During the actual test, the sample is allowed to be w

23、ired using a maximum of 8 ft of cable connected to boththe line and load side terminals.AUGUST 1, 2018UL 30046UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM UL5.2 Equipment ratings5.2.1 RATED CONTINUOUS CURRENT (Ith) The rated continuous curren

24、t is the maximum currentcarried on a continuous basis.5.2.2 RATED DURATION OF SHORT-TIME (tk) The rated duration of short-time withstand current isthe interval of time for which the equipment can carry a current equal to its rated short-time withstandcurrent (Ik). The preferred rated duration is 2 s

25、econds.5.2.3 RATED FREQUENCY (fr) The rated frequency is the supply frequency for which the junction boxis designed and to which the other characteristic values correspond. The standard values of the ratedfrequency are 50 Hz and 60 Hz. The preferred rated frequency is 60 Hz.5.2.4 RATED INSULATION LE

26、VEL (Ud), (Up) The rated insulation level is the impulse test voltage (BIL)(Up) and the power-frequency withstand test voltage (Ud) from Table 15.1 that the junction box is expectedto withstand.5.2.5 RATED MAXIMUM VOLTAGE (Ur) The rated maximum voltage indicates the upper limit of thehighest voltage

27、 of the system voltage for which the junction box or junction box is intended. Standardvalues of rated voltages are 2.5 kV, 3.6 kV, 5 kV, 7.2 kV, 12 kV, 15 kV, 27 kV, and 38 kV.5.2.6 RATED PEAK WITHSTAND CURRENT (Ip) The rated peak withstand current is the prospectivepeak current associated with the

28、 first major loop of the rated short-time withstand current that the junctionbox can withstand during the fault interruption test. The prospective peak current value shall be equal to2.6 times (60 Hz) or 2.5 times (50 Hz or below) the rated short-time withstand current. This may also bereferred to a

29、s the rated momentary withstand current.5.2.7 RATED SHORT-TIME WITHSTAND CURRENT (Ik) The rated short-time withstand current is themaximum symmetrical rms value of the short-circuit current that equipment can withstand for the ratedduration (tk). The preferred values are 40 kA and 50 kA.CONSTRUCTION

30、6 Enclosure6.1 General6.1.1 Unless specified otherwise in this standard, the enclosure shall comply with the Standard forEnclosures for Electrical Equipment, Non-Environmental Considerations, UL 50.6.1.2 The enclosure may be constructed with a special opening for connection to other equipment if the

31、enclosure is provided with mating surfaces of at least 9.5 mm (3/8 inch) on each side of the specialopening and is provided with instructions and markings as specified in Section 22.6.1.3 Enclosures shall be metallic. Portions of the enclosure may be of insulating material, provided thatmedium-volta

32、ge parts are completely enclosed by grounded metallic covers.AUGUST 1, 2018 UL 3004 7UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM UL6.1.4 The enclosure shall have no openings that are not closed when mounted as intended.6.1.5 Enclosures may b

33、e evaluated to specific enclosure types as specified in the Standard forEnclosures for Electrical Equipment, Environmental Considerations, UL 50E. Enclosures rated with anoutdoor type environmental rating shall be subjected to the driven rain test described in Section 16, inaddition to the appropria

34、te tests in UL 50Efor the assigned type rating(s).6.2 Exterior doors, covers, and similar parts of enclosures6.2.1 A part of the enclosure, such as a door or cover, shall be provided with means, such as latches,bolts or screws, for firmly securing it in place.6.2.2 Doors or covers shall require the

35、use of a tool to open them and may additionally have provisionsfor locking. A warning marking shall also be provided in accordance with 19.3.6.2.3 Doors shall be provided with a latch or with a captive fastener. Such fasteners shall be located orused in multiples so as to hold the cover closed over

36、its entire length. A door more than 1.2 m (4 ft) longon the hinged side shall have at least a two-point latch operated by a single knob or handle, or shall havetwo or more separate latches or captive fasteners.6.2.4 Doors and covers shall meet the following conditions:a) Doors shall be bolted on all

37、 unhinged sides with a minimum of two bolts per side;b) Covers shall be bolted with a minimum of two bolts per side;c) No bolts are operable by hand, without the use of a tool;d) All bolts are captive fasteners.6.2.5 All doors shall be capable of being opened to a minimum of 90 degrees from the clos

38、ed position.6.3 Inspection windows6.3.1 A transparent material covering an observation opening and forming a part of the enclosure shall:a) Be of clear safety-type glass or wire-reinforced glass or another clear material found suitablewith respect to flammability and UV resistance in accordance with

39、 the Standard for PolymericMaterials Use in Electrical Equipment Evaluations, UL 746C.b) Be secured in such a manner that it cannot be removed without tools; andc) Meet the requirements of impact and pressure tests for viewing panes specified in Section17.AUGUST 1, 2018UL 30048UL COPYRIGHTED MATERIA

40、L NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM UL6.4 Enclosure category6.4.1 All enclosures complying with 6.1 6.3 are considered to provide general protection againstincidental contact with live parts by unauthorized and untrained personnel. Enclosures intended to

41、provideadditional protection may be designated as Category A or B enclosures in accordance with 6.4.2 or 6.4.3.6.4.2 Category A enclosures are intended for installation in unsupervised areas accessible to the generalpublic where they may be subject to deliberate unauthorized acts to gain access to t

42、he interior of theenclosure. Such enclosures may be marked as Category A enclosures in accordance with 20.3, if theenclosure complies with all the requirements for Category A enclosures as detailed in Annex B of IEEEC37.20.2-2015.6.4.3 Category B enclosures are intended for installation in areas tha

43、t may be accessible to other thanauthorized personnel, but not expected to be subjected to deliberate unauthorized acts to gain access tothe interior of the enclosure. An enclosure may be marked as a Category B enclosure in accordance with20.4, if the enclosure complies with all the requirements for

44、 Category B enclosures as detailed in AnnexB of IEEE C37.20.2-2015.7 Wire Bending Space7.1 Wire-bending space for field-installed conductors7.1.1 Wire bending space shall be such that, during installation, field-installed conductors need not bebent to a radius less than:a) 8 times the overall diamet

45、er for non-shielded conductors; orb) 12 times the overall diameter for shielded or lead-covered conductors.Construction shall take into account the type and maximum size of wire, optional use of stress cones forfield terminations, and other instructions provided in accordance with 21.9.7.1.2 Junctio

46、n boxes rated over 5 kV shall always be provided with wire bending space based on the useof shielded conductors. Junction boxes rated 5 kV and below may be provided with wire bending spaceonly for non-shielded conductors when marked in accordance with 21.10.NOTE: Section 310.10 of NFPA 70 (National

47、Electrical Code) provides details for the use of shielded conductors.7.1.3 If the construction of the junction box is such that wire-bending space is available only on one sideof the termination point of the conductors, this shall be noted in the instructions provided in accordancewith 21.9.AUGUST 1

48、, 2018 UL 3004 9UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM UL8 Wiring Terminals8.1 Connection of current-carrying conductors8.1.1 Terminals for field connection of medium voltage conductors shall conform to any one of thefollowing:a) Bus ba

49、rs provided with hole patterns meeting the requirements of ANSI/NEMA CC1, ElectricPower Connection for Substations;b) Connectors complying with the Standard for Wire Connectors, UL 486A-486B, rated for theconductor size required based on the rated ampacity of the junction box; orc) Separable connectors complying with the Standard for Separable Insulated ConnectorSystems for Power Distribution Systems above 600 Volts, ANSI/IEEE 386, rated for theampacity of the junction box.8.2 Connection of conductor shields8.2.1 There shall be provisions for bondi