1、UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULUNDERWRITERS LABORATORIES INC. CERTIFICATION REQUIREMENT DECISIONThis Certification Requirement Decision is prepared by UL LLC. It is normative for the applicable ULProduct Certification Program(
2、s); however, it is currently not part of the UL Standard(s) referencedbelow.Product Category (CCN): ZCTT/ZCTT7Standard Number: UL 2157Standard Title: Standard for Electric Clothes Washing Machines and ExtractorsEdition Date: November 2, 2015Edition Number: 3Section / Paragraph Reference: 20.2.10Subj
3、ect: Metal Enclosure Thickness (where power-supply conductors enter theenclosure)DECISION:20.2.10 At a point where the power-supply conductors enter the enclosure, sheet metal shall not be lessthan 0.81 mm thick if uncoated steel, not less than 0.86 mm if galvanized steel, not less than 1.09 mm ifco
4、pper or brass, and not less than 1.12 mm if aluminum.20.2.10.1 Sheet metal enclosures with the dimensions specified in Tables 17.1 and 17.2 are consideredto comply with the intent of Clause 20.2.10.Table 17.1Thickness of carbon steel or stainless steel enclosuresWithout supporting frameaWith support
5、ing frame orequivalent reinforcingaMinimum thickness, mm (inch)MaximumwidthbMaximumlengthcMaximumwidthbMaximum length Uncoated Metal Coatedmm (inches) mm (inches) mm (inches) mm (inches)102 (4) Not limited 159 (6-1/4) Not limited0.51 (0.020)0.58 (0.023)121 (4-3/4) 146 (5-3/4) 171 (6-3/4) 210 (8-1/4)
6、152 (6) Not limited 241 (9-1/2) Not limited0.66 (0.026)0.74 (0.029)178 (7) 222 (8-3/4) 254 (10) 318 (12-1/2)NOTE - This table is based on a uniform deflection of the enclosure surface for any given load concentrated at thecenter of the surface regardless of metal thickness.aA supporting frame is a s
7、tructure of angle or channel or a folded rigid section of sheet metal that is rigidlyattached to and has essentially the same outside dimensions as the enclosure surface and that has sufficienttorsional rigidity to resist the bending moments that may be applied via the enclosure surface when it is d
8、eflected.Construction that is considered to have equivalent reinforcing may be accomplished by a structure that is as rigidas one built with a frame of angles or channels. Construction considered to be without supporting frame includes:Single sheet with single formed flanges (formed edges); a single
9、 sheet that is corrugated or ribbed; and Anenclosure surface loosely attached to a frame, for example, with spring clips.bThe width is the smaller dimension of a rectangular sheet metal piece that is part of an enclosure. Adjacentsurfaces of an enclosure are not prohibited from having supports in co
10、mmon and being made of a single sheet.cNot limited applies only where the edge of the surface is flanged at least 12.7 mm or fastened to adjacentsurfaces not normally removed in use.UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULTable 17.2Thi
11、ckness of aluminum, copper, or brass enclosuresWithout supporting frameaWith supporting frame or equivalentreinforcingaMinimum thicknessMaximum widthbMaximum lengthcMaximum widthbMaximum lengthmm (inches) mm (inches) mm (inches) mm (inches) mm (inches)76 (3) Not limited 178 (7) Not limited 0.58 (0.0
12、23)89 (3-1/2) 102 (4) 216 (8-1/2) 241 (9-1/2)102 (4) Not limited 254 (10) Not limited 0.74 (0.029)127 (5) 152 (6) 267 (10-1/2) 343 (13-1/2)152 (6) Not limited 356 (14) Not limited 0.91 (0.036)165 (6-1/2) 203 (8) 381 (15) 457 (18)NOTE - This table is based on a uniform deflection of the enclosure sur
13、face for any given load concentrated at thecenter of the surface regardless of metal thickness.aA supporting frame is a structure of angle or channel or a folded rigid section of sheet metal that is rigidlyattached to and has essentially the same outside dimensions as the enclosure surface and that
14、has sufficienttorsional rigidity to resist the bending moments that may be applied via the enclosure surface when it is deflected.Construction that is considered to have equivalent reinforcing may be accomplished by a structure that is as rigidas one built with a frame of angles or channels. Constru
15、ction considered to be without supporting frame includes:Single sheet with single formed flanges (formed edges); a single sheet that is corrugated or ribbed; and Anenclosure surface loosely attached to a frame, for example, with spring clips.bThe width is the smaller dimension of a rectangular sheet
16、 metal piece that is part of an enclosure. Adjacentsurfaces of an enclosure are not prohibited from having supports in common and being made of a single sheet.cNot limited applies only when the edge of the surface is flanged at least 12.7 mm (1/2 inch) or fastened toadjacent surfaces not normally re
17、moved in use.RATIONALE FOR DECISION:Clause 20.2.10 of UL 2157 specifies certain minimum thicknesses for sheet metal enclosures, dependingon the type of metal used.Other UL standards specify minimum thicknesses of metal enclosures that are also dependent on the sizeof the enclosure, namely the length
18、 and width of the enclosure, and whether the enclosure has asupporting frame. The dimensions in the above tables are based on a uniform deflection of the enclosuresurface for any given load concentrated at the center of the surface regardless of metal thickness, andcan be found in UL 1004-1 and UL 1
19、995, as well as other UL standards.This Certification Requirement Decision is intended to allow the same minimum thickness requirementsfound in other UL standards, and documents present practice in the application of these requirements.Copyright 2017 UL LLCUL LLC, in performing its functions in acco
20、rdance with its objectives, does not guarantee or warrant thecorrectness of Certification Requirement Decisions it may issue or that they will be recognized or adoptedby anyone. Certification Requirement Decisions are the opinion of UL LLC. in practically applying therequirements of the standard. Th
21、ey do not represent formal interpretations of the standard underAmerican National Standards Institute (ANSI) processes. UL LLC shall not be responsible to anyone forthe use of or reliance upon Certification Requirement Decisions by anyone. UL LLC shall not incur anyobligation or liability for damage
22、s, including consequential damages, arising out of or in connection withthe use or reliance upon Certification Requirement Decisions. The electronic version of the CertificationRequirement Decision is the current version and previously printed copies may be outdated.STANDARD NUMBER: UL 2157 -2-UL CO
23、PYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULThis document is published as a service to ULs certification customersSTANDARD NUMBER: UL 2157 -3-UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULSTANDARD NUMBER: UL 2157 -4-No Text on This Page
