UL 50-2003 Enclosures for Electrical Equipment.pdf

1、UL 50ISBN 1-55989-909-3Enclosures for ElectricalEquipmentUnderwriters Laboratories Inc. (UL)333 Pfingsten RoadNorthbrook, IL 60062-2096UL Standard for Safety for Enclosures for Electrical Equipment, UL 50Eleventh Edition, Dated October 19, 1995Revisions: This Standard contains revisions through and

2、including September 12, 2003.Summary of TopicsThis revision to ANSI/UL 50 is being issued to update the Title Page to indicate approval as anAmerican National Standard.UL Standards for Safety are developed and maintained in the Standard Generalized Markup Language(SGML). SGML - an international stan

3、dard (ISO 8879-1986) - is a descriptive markup language thatdescribes a documents structure and purpose, rather than its physical appearance on a page. Due toformatting differences resulting from the use of ULs new electronic publishing system, please note thatadditional pages (on which no requireme

4、nts have been changed) may be included in revision pages dueto relocation of existing text and reformatting of the Standard.Text that has been changed in any manner is marked with a vertical line in the margin. Changes inrequirements are marked with a vertical line in the margin and are followed by

5、an effective date noteindicating the date of publication or the date on which the changed requirement becomes effective.The revised requirements are substantially in accordance with ULs Bulletin(s) on this subject datedFebruary 13, 2003 and July 8, 2003. The bulletin(s) is now obsolete and may be di

6、scarded.The revisions dated September 12, 2003 include a reprinted title page (page1) for this Standard.As indicated on the title page (page 1), this UL Standard for Safety is an American National Standard.Attention is directed to the note on the title page of this Standard outlining the procedures

7、to be followedto retain the approved text of this ANSI/UL Standard.As indicated on the title page (page1), this UL Standard for Safety has been adopted by the Departmentof Defense.The master for this Standard at ULs Northbrook Office is the official document insofar as it relates to aUL service and

8、the compliance of a product with respect to the requirements for that product and service,or if there are questions regarding the accuracy of this Standard.ULs Standards for Safety are copyrighted by UL. Neither a printed copy of a Standard, nor the distributiondiskette for a Standard-on-Diskette an

9、d the file for the Standard on the distribution diskette should bealtered in any way. All of ULs Standards and all copyrights, ownerships, and rights regarding thoseStandards shall remain the sole and exclusive property of UL.All rights reserved. No part of this publication may be reproduced, stored

10、 in a retrieval system, ortransmitted in any form by any means, electronic, mechanical photocopying, recording, or otherwisewithout prior permission of UL.Revisions of UL Standards for Safety are issued from time to time. A UL Standard for Safety is currentonly if it incorporates the most recently a

11、dopted revisions.SEPTEMBER 12, 2003 UL 50 tr1UL provides this Standard as is without warranty of any kind, either expressed or implied, including butnot limited to, the implied warranties of merchantability or fitness for any purpose.In no event will UL be liable for any special, incidental, consequ

12、ential, indirect or similar damages,including loss of profits, lost savings, loss of data, or any other damages arising out of the use of or theinability to use this Standard, even if UL or an authorized UL representative has been advised of thepossibility of such damage. In no event shall ULs liabi

13、lity for any damage ever exceed the price paid forthis Standard, regardless of the form of the claim.UL will attempt to answer support requests concerning electronic versions of its Standards. However, thissupport service is offered on a reasonable efforts basis only, and UL may not be able to resol

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17、k of a single personal computer, or on a single LAN file-server or the permanent storagedevice of a multiple-user computer in such a manner that this Standard may only be accessed by one userat a time and for which there is no possibility of multiple concurrent access.If a multiple-user version elec

18、tronic Standard was purchased, one copy of the Standard may be stored ona single LAN file-server, or on the permanent storage device of a multiple-user computer, or on an Intranetserver. The number of concurrent users shall not exceed the number of users authorized.Electronic Standards are intended

19、for on-line use, such as for viewing the requirements of a Standard,conducting a word search, and the like. Only one copy of the Standard may be printed from eachsingle-user version of an electronic Standard. Only one copy of the Standard may be printed for eachauthorized user of a multiple-user ver

20、sion of an electronic Standard. Because of differences in thecomputer/software/printer setup used by UL and those of electronic Standards purchasers, the printedcopy obtained by a purchaser may not look exactly like the on-line screen view or the printed Standard.An employee of an organization purch

21、asing a UL Standard can make a copy of the page or pages beingviewed for their own fair and/or practical internal use.The requirements in this Standard are now in effect, except for those paragraphs, sections, tables, figures,and/or other elements of the Standard having future effective dates as ind

22、icated in the note following theaffected item. The prior text for requirements that have been revised and that have a future effective dateare located after the Standard, and are preceded by a SUPERSEDED REQUIREMENTS notice.New product submittals made prior to a specified future effective date will

23、be judged under all of therequirements in this Standard including those requirements with a specified future effective date, unlessthe applicant specifically requests that the product be judged under the current requirements. However, ifSEPTEMBER 12, 2003 UL 50tr2the applicant elects this option, it

24、 should be noted that compliance with all the requirements in thisStandard will be required as a condition of continued Listing, Recognition, Classification, and Follow-UpServices after the effective date, and understanding of this should be signified in writing.Copyright 2003 Underwriters Laborator

25、ies Inc.This Standard consists of pages dated as shown in the following checklist:Page Date1-3.September 12, 20034-6 .November 19, 19997-8B .September 12, 20039-10B .November 19, 199911.October 19, 199512-14B.November 19, 199915-16 .October 1, 199617-18B.November 19, 199919.October 1, 199620.October

26、 19, 199521-22 .November 19, 199923.October 19, 199524-24B .November 6, 199725-28 .November 19, 199928A-29 .October 1, 199630.October 19, 199531-32B .November 6, 199733-34.September 12, 200335-36B .November 6, 199737.October 19, 199538-40A.November 19, 199940B-41 .October 1, 199642.October 19, 19954

27、3 .September 12, 200344-47 .October 19, 199548.October 1, 199649.November 19, 199950.October 19, 199551.August 19, 199752.October 19, 199553-60 .November 19, 199961.October 1, 199662.October 19, 1995SA1-SA2 .October 19, 1995SEPTEMBER 12, 2003 UL 50 tr3SEPTEMBER 12, 2003 UL 50tr4No Text on This PageO

28、CTOBER 19, 1995(Title Page Reprinted: September 12, 2003)1UL 50Standard for Enclosures for Electrical EquipmentThe First and Second editions were titled Standard for Cabinets and CutoutBoxes. The Third Ninth editions were titled Standard for Cabinets and Boxes.First Edition March, 1916Second Edition

29、 March, 1929Third Edition February, 1941Fourth Edition May, 1956Fifth Edition November, 1962Sixth Edition October, 1970Seventh Edition June, 1975Eighth Edition April, 1980Ninth Edition September, 1988Tenth Edition July, 1992Eleventh EditionOctober 19, 1995The most recent designation of ANSI/UL 50 as

30、 an American National Standard(ANSI) occurred on August 19, 2003.This ANSI/UL Standard for Safety, which consists of the Eleventh edition withrevisions through September 12, 2003, is under continuous maintenance,whereby each revision is ANSI approved upon publication. Comments orproposals for revisi

31、ons on any part of the Standard may be submitted to UL at anytime. Written comments are to be sent to UL-RTP Standard Department, 12Laboratory Dr., P.O. Box 13995, Research Triangle Park, NC, 27709-3995.The Department of Defense (DoD) has adopted UL 50 on April 5, 1982 . Thepublication of revised pa

32、ges or a new edition of this Standard will not invalidatethe DoD adoption.An effective date included as a note immediately following certain requirementsis one established by Underwriters Laboratories Inc.Revisions of this Standard will be made by issuing revised or additional pagesbearing their dat

33、e of issue. A UL Standard is current only if it incorporates themost recently adopted revisions, all of which are itemized on the transmittal noticethat accompanies the latest set of revised requirements.ISBN 1-55989-909-3COPYRIGHT 1988, 2003 UNDERWRITERS LABORATORIES INC.ANSI/UL 50-2003SEPTEMBER 12

34、, 2003ENCLOSURES FOR ELECTRICAL EQUIPMENT - UL 502No Text on This PageCONTENTSFOREWORD .6INTRODUCTION1 Scope .72 Glossary .73 References .8A4 Units of Measurement .8ACONSTRUCTIONGENERAL5 General .9ENCLOSURES6 General .107 Polymeric Enclosures/Parts .137.1 General .137.2 Bonding .147.3 Nonmetallic-sh

35、eathed cable clamps .157.4 Rigid nonmetallic conduit .157.5 Rigid metallic conduit .157.6 Provisions for support or mounting .158 Openings in Enclosures .158.1 General .158.2 Equipment openings .158.3 Drainage openings .168.4 Mounting openings .168.5 Conduit knockouts and conduit openings .178.6 Additional openings .179 Observation Windows .1810 Thickness of Cast-Metal Enclosures .1811 Thickness of Sheet-Metal Enclosures .1912 Joints and Fastenings .2113 Notches .2114 Gaskets .24BPROTECTION AGAINST CORROSION15 Outdoor Enclosures .