1、NEMA Standards PublicationNational Electrical Manufacturers AssociationNEMA FU 1-2012Low Voltage Cartridge FusesNEMA FU 1-2012 Low Voltage Cartridge Fuses Published by National Electrical Manufacturers Association 1300 North 17th Street, Suite 900 Rosslyn, Virginia 22209 www.nema.org 2013 National E
2、lectrical Manufacturers Association. All rights, including translation into other languages, reserved under the Universal Copyright Convention, the Berne Convention for the Protection of Literary and Artistic Works, and the International and Pan American copyright conventions. FU 1-2012 Page ii 2013
3、 National Electrical Manufacturers Association NOTICE AND DISCLAIMER The information in this publication was considered technically sound by a consensus among persons engaged in its development at the time it was approved. Consensus does not necessarily mean there was unanimous agreement among every
4、 person participating in the development process. The National Electrical Manufacturers Association (NEMA) standards and guideline publications, of which the document herein is one, are developed through a voluntary standards development process. This process brings together volunteers and/or seeks
5、out the views of persons who have an interest in the topic covered by this publication. Although NEMA administers the process and establishes rules to promote fairness in the development of consensus, it does not write the documents, nor does it independently test, evaluate, or verify the accuracy o
6、r completeness of any information or the soundness of any judgments contained in its standards and guideline publications. NEMA disclaims liability for any personal injury, property, or other damages of any nature, whether special, indirect, consequential, or compensatory, directly or indirectly res
7、ulting from the publication, use of, application, or reliance on this document. NEMA disclaims and makes no guaranty or warranty, express or implied, as to the accuracy or completeness of any information published herein, and disclaims and makes no warranty that the information in this document will
8、 fulfill any particular purpose(s) or need(s). NEMA does not undertake to guarantee the performance of any individual manufacturers or sellers products or services by virtue of this standard or guide. In publishing and making this document available, NEMA is not undertaking to render professional or
9、 other services for or on behalf of any person or entity, nor is NEMA undertaking to perform any duty owed by any person or entity to someone else. Anyone using this document should rely on his or her own independent judgment or, as appropriate, seek the advice of a competent professional in determi
10、ning the exercise of reasonable care in any given circumstance. Information and other standards on the topic covered by this publication may be available from other sources, which the user may wish to consult for additional views or information not covered by this publication. NEMA has no power, nor
11、 does it undertake to police or enforce compliance with the contents of this document. NEMA does not certify, test, or inspect products, designs, or installations for safety or health purposes. Any certification or other statement of compliance with any health- or safety-related information in this
12、document shall not be attributable to NEMA and is solely the responsibility of the certifier or maker of the statement. FU 1-2012 Page iii 2013 National Electrical Manufacturers Association TABLE OF CONTENTS Page Foreword . v Section 1 GENERAL 1.1 Scope .1 Section 2 DEFINITIONS AND ABBREVIATIONS 2.1
13、 Definitions .2 Section 3 SERVICE CONDITIONS 3.1 Usual Service Conditions 4 3.2 Unusual Service Conditions .4 Section 4 RATINGS 4.1 Current Ratings of Non Time-Delay Fuses 5 4.2 Current Ratings of Time-Delay Fuses .6 4.3 AC Voltage Ratings 6 4.4 DC Voltage Ratings 7 4.5 AC Interrupting Ratings .7 4.
14、6 DC Interrupting Ratings .7 4.7 Frequency Rating .7 Section 5 FUSE CLASSES 5.1 Summary of Fuse Classes 8 5.2 Class G Fuses (Current Limiting) 0-60 Amperes, 480 V and 600 V Alternating Current .8 5.3 Class H Fuses 0-600 Amperes, 250 V and 600 V Alternating Current8 5.4 Class J Fuses (Current Limitin
15、g) 0-600 Amperes, 600 V, Alternating Current .8 5.5 Class K Fuses 0-600 Amperes, 250 V and 600 V, Alternating Current.8 5.6 Class L Fuses (Current Limiting) 601-6000 Amperes, 600 V, Alternating Current 8 5.7 Class R Fuses (Current Limiting) 0-600 Amperes, 250 V and 600 V, Alternating Current .8 5.8
16、Class T Fuses (Current Limiting) 0-1200 Amperes, 300 V and 600 V, Alternating Current9 5.9 Class CC Fuses (Current Limiting) 0-30 Amperes, 600 Volts, Alternating Current .9 5.10 Fuses for Photovoltaic Systems (Current Limiting) PV fuses 9 Section 6 PERFORMANCE 6.1 General . 22 6.2 Current Carrying C
17、apacity and Temperature Rise Tests . 22 6.3 Overload Opening Time . 25 6.4 Interrupting Tests at Rated Voltage 25 6.4.1 Overload Tests .27 6.4.2 10,000 Amperes Short Circuit Tests 27 FU 1-2012 Page iv 2013 National Electrical Manufacturers Association 6.4.3 Interrupting Rating and Intermediate Inter
18、ruption Level Tests 27 6.5 Maximum Energy . . 35 6.6 Maximium Threshold Ratio 35 6.7 Direct Current Tests . 35 6.7.1 Overload Test. 35 6.7.2 Short Circuit Test 35 6.8 Direct Current Tests for Photovoltaic Fuses . 36 6.8.1 Verification of Temperature Rise and Current-Carrying Capacity 36 6.8.2 Verifi
19、cation of Overload Operation .36 6.8.3 Verification of Operation Rated Voltage . 37 6.8.4 Verification of Peak Let-Through Characteristics and 2t .37 6.8.5 Verification of Freedom From Unacceptable Levels of Thermally Induced Drift .37 6.8.6 Verification of Functionality at Temperature Extremes 37 6
20、.8.7 Current Cycling-Temperature. 37 6.8.8 Current Cycling-Humidity 38 FU 1-2012 Page v 2013 National Electrical Manufacturers Association Foreword These standards have been developed by the Low Voltage Fuse Section of NEMA. The purpose of this standards publication is to assist in the proper select
21、ion and application of the different classes of low voltage cartridge fuses. User needs have been considered throughout the development of these standards. NEMA standards publications are subject to periodic review. They are revised frequently to meet changing conditions and technical progress. The
22、user should secure the latest editions. Proposed or recommended revisions should be submitted to: Senior Technical Director, Operations National Electrical Manufacturers Association 1300 North 17th Street, Suite 900 Rosslyn, VA 22209 This standards publication was developed by the Fuse Section. Sect
23、ion approval of the standard does not necessarily imply that all section members voted for its approval or participated in its development. At the time it was approved, the group/section was composed of the following members: Cooper Bussmann St. Louis, MO Ferraz Shawmut Newburyport, MA Littelfuse De
24、sPlaines, IL Eagle Long Island, NY FU 1-2012 Page 1 2013 National Electrical Manufacturers Association Section 1 GENERAL 1.1 SCOPE This standards publication covers the following fuses: a. Class G, H, J, K, L, R, T, and CC low voltage cartridge fuses rated 600 volts or less, alternating current and
25、direct current. b. Fuses for photovoltaic systems rated 1500 volts or less direct current. FU 1-2012 Page 2 2013 National Electrical Manufacturers Association Section 2 DEFINITIONS AND ABBREVIATIONS 2.1 DEFINITIONS ambient temperature: The temperature of the air surrounding the fuse. arcing time: Th
26、e time from the instant the fuse element or link has melted and arcing is initiated until final circuit interruption by the fuse. body: The part of the fuse that encloses the fuse elements and supports the contacts. Also referred to as cartridge, tube, or case. cartridge fuse: A fuse consisting of a
27、 current responsive element inside a fuse body with contacts on both ends. cartridge or body size: The set of dimensions of fuses within a fuse class or system. Each individual size covers a given range of rated currents for which the specified dimensions of the fuse remain unchanged. clearing I2t (
28、ampere squared seconds): The measure of heat energy developed during current interruption from the initiation of an overcurrent until the fuse clears the circuit. “I2“ stands for the square of the effective (rms) let-through current and “t“ stands for the time of current flow in seconds. The term I2
29、t also applies during the melting or arcing portions of the clearing time and is referred to as melting or arcing I2t respectively. Clearing I2t is the sum of melting I2t and arcing I2t. contacts: The external metallic parts of the fuse used to complete the circuit. Also referred to as ferrules, cap
30、s, blades, or terminals. current-limiting fuse: A fuse that, within a specified overcurrent range, limits the clearing time at rated voltage to an interval equal to or less than the first major or symmetrical current loop duration; and limits peak let-through current to a value less than the availab
31、le peak fault current. current-limiting range: The range of currents from the threshold current to the interrupting current rating of a fuse. current rating (In): The nominal rms AC or DC ampere rating, based on specified conditions, which is assigned to a fuse. element: The fusible portion of the f
32、use that melts during an overcurrent condition to clear the circuit. Also referred to as a link. filler: A material used to fill a section or sections of a fuse. fuse: A protective device that opens a circuit during specified overcurrent conditions by means of a current responsive element. interrupt
33、ing rating: The highest prospective rms symmetrical alternating current or direct current that the fuse is required to interrupt under specified conditions verified by operation at rated voltage. FU 1-2012 Page 3 2013 National Electrical Manufacturers Association maximum energy: A test condition tha
34、t causes a fuse to experience maximum energy during interruption within the first cycle. melting time: The time from the initiation of an overcurrent to the instant arcing of the element begins. overcurrent: Any current in excess of the fuse current rating. peak arc voltage: The maximum peak voltage
35、 across the fuse during the arcing time. peak let-through current Ip: The maximum instantaneous current through a fuse during interruption in its current-limiting range. rating: A designated limit of an operating characteristic under defined conditions. recovery voltage: The normal frequency rms vol
36、tage impressed upon the fuse after the circuit has been interrupted. rejection feature: A physical characteristic of a fuse and fuse holder (slot, groove, pin, or overall dimension) that normally prevents substitution by other rating or classes of fuses. renewal element (renewal link): That part of
37、a renewable fuse that is replaced after each interruption. renewable fuse: A fuse that may be readily restored for service after interruption by the replacement of the renewal elements. threshold current: The lowest prospective rms symmetrical current for which the fuse is current limiting, under sp
38、ecific test conditions. threshold ratio: The threshold current divided by the fuse current rating. time-delay fuse: A fuse capable of carrying a specified overcurrent for a specified minimum time. voltage rating: The maximum rms AC voltage or DC voltage for which the fuse is designed to operate.FU 1
39、-2012 Page 4 2013 National Electrical Manufacturers Association Section 3 SERVICE CONDITIONS 3.1 USUAL SERVICE CONDITIONS Fuses conforming to these standards shall operate in a clean, dry environment within their ratings provided: a. The temperature of the air surrounding the fuse is within the rang
40、e of -40 C to +55 C whether or not the fuse is in an enclosure. b. The altitude does not exceed 3030 m (10,000 feet). 3.2 UNUSUAL SERVICE CONDITIONS For unusual service conditions the manufacturer should be consulted. FU 1-2012 Page 5 2013 National Electrical Manufacturers Association Section 4 RATI
41、NGS 4.1 CURRENT RATINGS OF NON TIME-DELAY FUSES The typical current ratings of Non Time-Delay fuses shall be as shown in Table 4-1. Table 4-1 CURRENT RATINGS OF NON TIME-DELAY FUSES Cartridge Size Current Ratings (Amperes) (Amperes) 0-30 1, 3, 6, 10, 15, 20, 25, 30 31-60 35, 40, 45, 50, 60 61-100 70
42、, 80, 90, 100 101-200 110, 125, 150, 175, 200 201-400 225, 250, 300, 350, 400 401-600 450, 500, 600 601-800 601, 700, 800 801-1200 1000, 1200 1201-1600 1600 1601-2000 2000 2001-2500 2500 2501-3000 3000 3001-4000 4000 4001-5000 5000 5001-6000 6000 FU 1-2012 Page 6 2013 National Electrical Manufacture
43、rs Association 4.2 CURRENT RATINGS OF TIME-DELAY FUSES The typical current ratings of Time-Delay fuses shall be as shown in Table 4-2. Table 4-2 CURRENT RATINGS OF TIME-DELAY FUSES Cartridge Size Current Ratings (Amperes) (Amperes) 0-30 1/10, 15/100, 2/10, 3/10, 4/10, 1/2, 6/10, 8/10, 1, 1 1/8, 1 1/
44、4, 1-4/10, 1-6/10, 1-8/10, 2, 2-1/4, 2-1/2, 2-8/10, 3, 3-2/10, 3-1/2, 4, 4-1/2, 5, 5-6/10, 6, 6-1/4, 7, 8, 9, 10, 12, 15, 17-1/2,20, 25, 30 31-60 35, 40, 45, 50, 60 61-100 70, 80, 90, 100 101-200 110, 125, 150, 175, 200 201-400 225, 250, 300, 350, 400 401-600 450, 500, 600 601-800 601, 700, 800 801-
45、1200 1000, 1200 1201-1600 1600 1601-2000 2000 2001-2500 2500 2501-3000 3000 3001-4000 4000 4001-5000 5000 5001-6000 6000 4.3 AC VOLTAGE RATINGS The alternating current voltage ratings for time-delay and non-time-delay fuses shall be as shown in Table 4-3. Table 4-3 AC VOLTAGE RATINGS TIME-DELAY AND
46、NON-TIME-DELAY FUSES 125 V 250 V 300 V 480 V 600 V FU 1-2012 Page 7 2013 National Electrical Manufacturers Association 4.4 DC VOLTAGE RATINGS The preferred direct current voltage ratings for time delay and non-time-delay fuses shall be as shown in Table 4-4. Table 4-4 DC VOLTAGE RATINGS TIME-DELAY A
47、ND NON-TIME-DELAY FUSES 60 V 125 V 160 V 250 V 300 V 400 V 500 V 600 V 750 V 1000 V 1250 V 1500 V 4.5 AC INTERRUPTING RATINGS The alternating current interrupting ratings for both time-delay and non-time-delay fuses in AC amperes shall be as shown in Table 4-5. Table 4-5 AC INTERRUPTING RATINGS TIME
48、-DELAY AND NON-TIME-DELAY FUSES 10,000 A 50,000 A 100,000 A 200,000 A 300,000 A 4.6 DC INTERRUPTING RATINGS The preferred direct current interrupting ratings for time-delay and non-time-delay fuses in DC amperes shall be as shown in Table 4-6. Table 4-6 DC INTERRUPTING RATINGS TIME-DELAY AND NON-TIME-DELAY FUSES 10,000 A 20,000 A 50,000 A 100,000 A 150,000 A 200,000 A 4.7 FREQUENCY RATING The alternating current frequency rating shall be 48-62 Hertz. FU 1-2012 Page 8 2013 National Elect
