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1、UL 943A 73 7275795 0560374 TO7 E UL 943A Copyright Underwriters Laboratories Inc. Provided by IHS under license with ULLicensee=North Carolina State University/5618801100 Not for Resale, 10/14/2006 11:09:52 MDTNo reproduction or networking permitted without license from IHS -,-,- UL 943A 93 m 927579
2、5 0560375 943 m Northbrook, Illinois. (708) 272-8800 Melville, New York. (516) 271-6200 Santa Clara, California. (408) 985-2400 Research Triangle Park, North Carolina. (919) 549-1400 O Underwriters Laboratories Inc., Underwriters Laboratories Inc., founded in 1894, is chartered as a not-for-profit o
3、rganization without capital stock, under the laws of the State of Delaware, to establish, maintain, and operate laboratories for the examination and testing of devices, systems and materials to determine their relation to hazards to life and property, and to ascertain, define and publish standards,
4、classifications and specifications for materials, devices, products, equipment, constructions, methods, and systems affecting such hazards. UL Standards for Safety are developed under a procedure which provides for participation and comment from the affected public as well as industry. The procedure
5、 takes into consideration a survey of known existing standards and the needs and opinions of a wide variety of interests concerned with the subject matter of the standard. Thus manufacturers, consumers, individuals associated with consumer-oriented organizations, academicians, government officials,
6、industrial and commercial users, inspection authorities, insurance interests and others provide input to UL in the formulating of UL Standards for Safety, to keep them consonant with social and technological advances. A not-for-profit organization dedicated to public safety and committed to quality
7、service Copyright Underwriters Laboratories Inc. Provided by IHS under license with ULLicensee=North Carolina State University/5618801100 Not for Resale, 10/14/2006 11:09:52 MDTNo reproduction or networking permitted without license from IHS -,-,- UL 943A 73 9275795 0560376 88T = nderwriters Laborat
8、ories 1nc.B A not-for-profa organization dedicated t o public safety and committed t o qwi service December 2 9 , 1993 Standard for Leakage Current Protection Devices UL 943A, First Edition . Accompanying this transmittal notice is a copy of the First edition of UL 943A. THIS EDITION OF THE STANDARD
9、 I S NOW IN EFFECT. The requirements in this standard are substantially in accordance with Urs bulletin on this subject dated February 10, 1993. This bulletin is now obsdete and may be discarded. Revised and/or additional pages may be issued from time to time. Subscribers to ULs services in the area
10、 covered by this standard will receive these revised and/or additional pages automatically. Others may receive such pages by subscribing to ULs subscription service for revisions. See ULs CATALOG OF STANDARDS FOR SAFEpr for a description of the revision subscription service, the cost of the service
11、for this standard, and ordering information. Copyright Underwriters Laboratories Inc. Provided by IHS under license with ULLicensee=North Carolina State University/5618801100 Not for Resale, 10/14/2006 11:09:52 MDTNo reproduction or networking permitted without license from IHS -,-,- UL 943A 93 W 92
12、75795 0560377 736 W DECEMBER 29, 1993 1 UL 943A Reference Standard for Leakage Current Protection Devices First Edition December 29, 1993 An effective date induded as a note immediately following cei in requirements is one established by Underwriters Laboratories Inc. Revisions of this standard will
13、 be made by issuing revised or additional pages bearing their date of issue. A UL Standard is current only if it incorporates the most recently adopted revisions, all of which are itemized on the transmittal notice that accompanies the latest published set of revision pages. ISBN 1-55989-521-7 COPYR
14、IGHT 01993 UNDERWRITERS LABORATORIES INC. ULs Standards for Safety are copyrighted to protect ULs publication rights, not to restrict their use in product design or evaluation. See paragraph E of the Foreword. Il - 12/29/93 - 12/29/93) Copyright Underwriters Laboratories Inc. Provided by IHS under l
15、icense with ULLicensee=North Carolina State University/5618801100 Not for Resale, 10/14/2006 11:09:52 MDTNo reproduction or networking permitted without license from IHS -,-,- UL 943A 93 9275795 05bOL78 652 DEaiMBER 29,1093 LEAKAGE CURRENT PROTECTION DEVICES - UL 943A 3 CONTENTS FOREWORD INTRODUCTIO
16、N 1 scope 5 2 Glossary 5 3 General 9 4 Installation and Use of Ground-Fault Circuit-Interrupters 12 Copyright Underwriters Laboratories Inc. Provided by IHS under license with ULLicensee=North Carolina State University/5618801100 Not for Resale, 10/14/2006 11:09:52 MDTNo reproduction or networking p
17、ermitted without license from IHS -,-,- UL 943A 93 = 9275795 0560179 599 4 LEAKAGECURRENTPROTECTIONDEVICES - UL943A DECEMBER a, 1993 FOREWORD A. This Standard contains basic requirements for products covered by Underwriters Laboratories Inc. (UL) under its Fdlow-p Service for this category within th
18、e limitations given below and in the Scope section of this Standard. These requirements are based upon sound engineering principles, research, records of tests and field experience, and an appreciation of the problems o f manufacture, installation, and use derived from consultation with and informat
19、ion obtained from manufacturers, users, inspection authorities, and others having specialized experience. They are subject to revision as further experience and investigation may show is necessary or desirable. B. continued coverage of the manufacturers product. The observance of the requirements of
20、 this Standard by a manufacturer is one of the conditions of the C. A product which complies with the text of this Standard will not necessarily be judged to comply with the Standard if, when examined and tested, it is found to have other features which impair the level of safety contemplated by the
21、se requirements. D. A product employing materials or having forms of construction differing from those detailed in the requirements of this Standard may be examined and tested according to the intent of the requirements and, if found to be substantially equivalent, may be judged to comply with the S
22、tandard. E . UL, in performing its functions in accordance with its objectives, does not assume or undertake to discharge any responsibility of the manufacturer or any other party. The opinions and findings of UL represent its professional judgment given with due consideration to the necessary limit
23、ations of practical operation and state of the art at the time the Standard i s processed. UL shall not be responsible to anyone for the use of or reliance upon this Standard by anyone. UL shall not incur any obligation or liability for damages, including consequential damages, arising out of or in
24、connection with the use, interpretation of, or reliance upon this Standard. , F. personnel and property shall be employed in conducting such tests. Many tests required by the Standards of UL are inherently hazardous and adequate safeguards for Copyright Underwriters Laboratories Inc. Provided by IHS
25、 under license with ULLicensee=North Carolina State University/5618801100 Not for Resale, 10/14/2006 11:09:52 MDTNo reproduction or networking permitted without license from IHS -,-,- UL 943A 93 m 9275795 05bOLO 200 m DECEMBER 29,1963 =GE CURRENT PROTECTION DEVICES - UL M3A 5 INTRODUCTION 1 Scope 1.
26、1 This standard is intended to address the use and applications of leakage current protection devices. It describes the different types of leakage current protection devices available, including their features and limitations. 1.2 This standard does not contain any construction or performance requir
27、ements for leakage current protection devices. Ground-fault circuit-interrupters, equipment leakage current interrupters, and appliance leakage circuit interrupters are investigated in accordance with the Standard for Ground-Faul Circuit- Interrupters, UL 943. Immersiondetection circuit-interrupters
28、 are investigated in accordance with the Standard for Immersion-Detection Circuit-Interrupters, UL 1664. 1.3 A product that contains features, characteristics, components, materials, or systems new or different from those in use when the Standard was developed, and that involves a risk of fire, elec
29、tric shock, or injury to persons, shall be evaluated using the appropriate additional component and end-product requirements as determined necessary to maintain the level of safety for the user of the product as originally anticipated by the intent of this Standard. 2 Glossary 2.1 For the purposes o
30、f this Standard, the following definitions apply. 2.2 APPLIANCE LEAKAGE CURRENT INTERRUPTER (ALCI) - An ALCI is a device intended to be used in conjunction with an electrical appliance whose function is to interrupt both conductors of the electric circuit to a load when a fault current to ground exc
31、eeds 4 - 6 mA and is less than that required to operate the overcurrent protection device of the circuit. The ALCI is intended to be used only in a circuit that has a solidly grounded neutral conductor, and is not intended to be used in place of a GFCI in applications where the GFCI is required. ALC
32、ls are considered “personal protection“ devices and contain the following features: a) Can function in either line polarity, and b) Other features may or may not be provided. 2.3 attended; for example, electric kniies, can openers, hair dryers, and the like. ATTENDED INTERMITTENT-DUTY - Intended for
33、 infrequent and short-time use, and used only while 2.4 in an attachment plug. CORD-CONNECTED - Connected to a power supply circuit by means of a flexible cord terminating 2.5 EQUIPMENT LEAKAGE CURRENT INTERRUPTER (ELCI) - The ELCI is a device intended to provide leakage current protection in applia
34、nces and utilization equipment whose function is to interrupt all ungrounded conductors of the supply circuit to electrical equipment in the event a current, in excess of the trip current, occurs between live parts and the grounded enclosure or other grounded parts. An ELCI is not intended to be use
35、d in place of a GFCI, ALCI or IDCI and may have any trip current value greater than 6 mA. The use of an ELCI is not intended to replace or supersede the overcurrent protection requirements of an appliance or the National Electrical Code. The basic standard used to investigate these products is the S
36、tandard for Ground-Fault Circuit-Interrupters, UL 943, excfuding requirements concerning trip current and time. ELCls are considered “equipment protection“ devices. Copyright Underwriters Laboratories Inc. Provided by IHS under license with ULLicensee=North Carolina State University/5618801100 Not f
37、or Resale, 10/14/2006 11:09:52 MDTNo reproduction or networking permitted without license from IHS -,-,- UL 943A 93 9275795 0560181 l Y 7 6 -GE CURRENT PROTECTION DEVICES - UL 943A DECEMBER 29,1993 a 2.6 GROUND-FAULT CIRCUTT-INTERRUPTER (GFCI) - A general use device intended to be used in accordance
38、 with the National Elecbical Code. The GFCI is a device whose function is to interrupt the electric circuit to a load when a fault current to ground exceeds 6 mA for class A and 20 mA for Class B GFCls. The trip current value is less than that required to operate the overcurrent protection device of
39、 the circuit. A GFCI is intended to be used only in a circuit that has a solidly grounded neutral conductor. GFCls do not need a grounding conductor to operate properiy. GFCls are considered “personai protection“ devices, and have the foilowing features: - a) normal. Portable GFCls and receptade-typ
40、e GFCls function with line polarity reversed as weil as b) Portable GFCls protect against open line neutrais. c) GFCls are required to provide grounded neutral protection. d) GFCls are manually resettable. e) GFCls operate in ambients from -%OC (-31 O F ) to +=OC (149OF). 9 breaker or in a separate
41、outlet box GFCls may be part of an attachment plug, the power supply cord, a receptacle, a circuit 2.7 GROUND FAULT SENSING AND RELAYING EQUIPMENT - These devices are intended for use in power distribution systems rated 600 volts maximum. These devices are considered “equipment protection“ devices a
42、nd operate to cause a disconnecting means to function at predetermined values of ground fault current in accordance with the National Electrical Code. The basic standard used to investigate these devices is the Standard for Ground Fault Sensing and Relaying Equipment, UL 1053. 2.8 GROUNDED NEUTRAL P
43、ROTECTION - Operation of the protective device is maintained when the neutral conductor, which is normaily grounded at the supply source in accordance with the National Electric Code, becomes grounded at the load side of the protective device. This condition might otherwise cause the protective devi
44、ce to become desensitized, and its ability to sense a ground fault and interrupt the circuit may have become impaired. This is illustrated in Figure 2.1. Copyright Underwriters Laboratories Inc. Provided by IHS under license with ULLicensee=North Carolina State University/5618801100 Not for Resale,
45、10/14/2006 11:09:52 MDTNo reproduction or networking permitted without license from IHS -,-,- UL 943A 93 9275795 05b0182 083 DECEMBER 29,1993 LEAKAGE CURRENT PROTECTION DEVICES - UL 943A 7 Black I , If - Ulf I/ c I - - Ground Fault Current If - - A portion of the Ground Fault Current returning throu
46、gh the ground to load neutral fault df flf - df) - - The reduced ground fault current Because the ground fault current (if) is reduced (by df), the protective device would ordinarily just respond to the lower fault current, (If - and possibly take longer to trip than it would with the full fault cur
47、rent (If). In general, protective devices with Grounded Neutral Protection will trip as soon as a grounded neutral condition is detected. 2.9 IMMERSION-DETECTION CIRCUIT-INTERRUPTER (IDCI) - The IDCI is a device intended to be used with dectric appliances whose function is to interrupt both conducto
48、rs of the electric circuit to a load in the event of an unintentional immersion of the appliance. It is intended to interrupt the circuit when the leakage current between the sense lead and either circuit conductor exceeds the trip current value. The trip current may be any value below 6 mA sufficient to detect immersion of the connected appliance. Its function is not to be dependent on the presence of a grounded object. The IDCI is considered to be a “personal protection“ device. IDCls are not intended to be used in place o