CSA C22.2 No. 248.1:11

National Standard of Canada

(reaffirmed 2020)

Low-voltage fuses — Part 1: General requirements

REVISED SEPTEMBER 2020

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Revision History

CSA C22.2 No. 248.1:11, Low-voltage fuses — Part 1: General requirements

National Standard of Canada — September 2020

Outside front cover, National Standard of Canada text, and title page.

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National Standard of Canada

CSA C22.2 No. 248.1:11

Low-voltage fuses — Part 1: General requirements

®A trademark of the Canadian Standards Association, operating as “CSA Group”

ICS 29.120.50

ISBN 978-1-55491-642-9

Association of Standardization and Certification NMX-J-009/248/1-ANCE

Second Edition

Canadian Standards Association CSA C22.2 No. 248.1-11

Third Edition

Underwriters Laboratories Inc. UL 248-1

Third Edition

Low-Voltage Fuses – Part 1: General Requirements

May 13, 2011

(Title Page Reprinted: June 16, 2017)

ANSI/UL 248-1-2017

Update No. 2

C22.2 No. 248.1-11

May 2017

Note: For information about the Standards Update Service or if you are missing any updates, go to

shop.csa.ca or e-mail techsupport@csagroup.org.

Title: Low-voltage fuses – Part 1: General requirements — originally published May 2011

Revisions issued: Update No. 1 — August 2011

The following revisions have been formally approved and are marked by a vertical line in the margin on the attached replacement pages:

• Update your copy by inserting these revised pages.

• Keep the pages you remove for reference.

Association of Standardization and Certification NMX-J-009/248/1-ANCE

Second Edition

Canadian Standards Association CSA C22.2 No. 248.1-11

Third Edition

Underwriters Laboratories Inc. UL 248-1

Third Edition

Low-Voltage Fuses – Part 1: General Requirements

May 13, 2011

(Title Page Reprinted: June 22, 2011)

ANSI/UL 248-1-2011

MAY 13, 2011 NMX-J-009/248/1-ANCE  CSA C22.2 NO. 248.1-11  UL 248-1 3

CONTENTS

Preface 5

1. General 7

   1. Scope 7

   2. Object 7

2. Definitions 7

   1. Fuse 7

   2. General terms 8

   3. Characteristic quantities 10

3. Service conditions 12

4. Classification 12

5. Characteristics 12

   1. Summary of Characteristics 12

   2. Voltage rating 13

   3. Current rating 13

   4. Frequency rating 13

   5. Interrupting rating 13

   6. Peak let-through current and clearing I2t characteristics 13

6. Marking 13

   1. Marking of fuses 13

   2. Marking symbols 14

7. Construction 14

   1. Dimensions 14

   2. Current-carrying parts 14

   3. Connections 14

   4. Adhesives 14

   5. Contact alignment 15

   6. Body 15

   7. Corrosion protection 15

8. Tests 15

   1. General 15

   2. Verification of temperature rise and current-carrying capacity 17

   3. Verification of overload operation 20

   4. Verification of operation at rated voltage 21

   5. Verification of peak let-through current and clearing I2t characteristics 26

ANNEX A (normative)

Circuit calibration for interrupting rating tests

A1 Galvanometers 27

A2 Circuit calibration 28

A3 DC circuit calibration example 30

4 NMX-J-009/248/1-ANCE  CSA C22.2 NO. 248.1-11  UL 248-1 MAY 13, 2011

ANNEX B (normative)

Instrumentation for interrupting rating tests

B1 Power factor determination 32

B2 Available current 34

B3 Peak let-through current 34

B4 Recovery voltage 36

B5 Comparison of instrumentation 39

B6 Determination of I2t 39

B7 Oscillogram example 39

MAY 13, 2011 NMX-J-009/248/1-ANCE  CSA C22.2 NO. 248.1-11  UL 248-1 7

Low-Voltage Fuses – Part 1: General Requirements

1. General

   
   

   1. Scope

      
      

      1. This Standard applies to low-voltage fuses rated 1000 V or less, AC and/or DC, with interrupting ratings up to 200 kA. These fuses are intended to be used in accordance with the Canadian Electrical Code, Part I (CEC), and the National Electrical Code, NFPA 70 (NEC).

         
         

   2. Object

      
      

      1. This Standard and its subsequent Parts establish the characteristics, construction, operating conditions, markings, and test conditions for each of the fuse classes so that initial investigation and follow-up verification can be performed in an orderly manner.

         
         

2. Definitions

   
   

   The following definitions apply in this Standard.

   
   

   Note: The Clauses in Definitions, Clause 2, are numbered corresponding to the Clause numbers for definitions for the similar items contained in the International Electrotechnical Commission Publication 269-1: Low-voltage fuses, Part 1: General requirements. Some Clause numbers are omitted.

   
   

   1. Fuse

2.1.3 Fuse

A protective device which opens a circuit during specified overcurrent conditions by means of a current responsive element.

2.1.3.1 Body

The part of the fuse which encloses the fuse elements and supports the contacts. Also referred to as cartridge, tube, or case.