BS 1361:1971

Cooperating organizations
Foreword
Specification
1. General
1.1 Scope
1.2 Service conditions
1.3 Definitions
2. Fuse Links
2.1 Ratings
2.1.1 Rating of fuse link
2.1.2 Rated voltages
2.1.3 Breaking capacity rating
2.1.4 Current rating
2.1.5 Fusing factor
2.2 Performance
2.2.1 Power loss
2.2.2 Time/current zones
2.2.3 Time/current characteristic
2.2.4 Fusing factor
2.2.5 Breaking performance
2.2.6 Discrimination
2.3 Construction
2.3.1 Dimensions
2.3.2 End caps
2.4 Marking
2.5 Type tests
2.5.1 Type II fuse links of lower current rating
2.5.2 Power loss tests
2.5.3 Tests of time/current characteristics and
        fusing factor
2.5.4 Preparation of fuses for breaking capacity tests
2.5.5 Breaking capacity tests
2.5.6 Criteria of failure in breaking capacity tests
2.5.7 Verification of discrimination
3. Fuse Carriers and Bases
3.1 Ratings
3.1.1 Ratings of fuse carriers and bases
3.1.2 Voltage rating
3.1.3 Current rating
3.2 Performance
3.2.1 Temperature rise at current rating
3.3 Construction
3.3.1 Dimensions
3.3.2 Mechanical Strength
3.3.3 Contacts
3.3.4 Terminals
3.3.5 Non-metallic parts
3.3.6 Non-interchangeability
3.3.7 Shielding
3.4 Type tests
3.4.1 General
3.4.2 Tests for insulation resistance
3.4.3 Tests for temperature rise at current rating
3.4.4 High voltage test
3.4.5 Tests for mechanical strength
3.5 Marking
Appendices
A. Notes on terms
B. Standard graph sheet for the presentation of time/
     current characteristics
C. Test rig for tests for breaking capacity
D. Standard test rig for power loss tests
E. Measurement of prospective current and cut-off
     current
F. Computation of power factor from oscillograms
G. Measurement of recovery voltage and arc voltage
J. Application of fuse links
L. Information to be included in a report of type
     tests for breaking capacity on cartridge fuse
     links
M. Power loss
Tables
1. Breaking capacity and power factor
2. Current ratings
3. Test conductor sizes and maximum power loss
4. Dimensions of fuse links
5. Colour coding for Type I fuse links
6A. Values for pre-arcing and total I2t of Type I fuse
     links
6B. Values for pre-arcing I2t of Type II fuse links
7. Sizes of test conductors and terminal bores
8. Test currents for mechanical strength of Type II
     fuses
Figures
1. Dimensions of fuse link
2. Diagram of connections for tests for duty
3. Standard test rigs for power loss tests
4. Arrangement of test rig for breaking capacity test
5a. Time/current zones for 5 A, 20 A and 45 A fuse
     links
5b. Time/current zones for 15 A and 30 A fuse links
5c. Time/current zones for 80 A fuse links
5d. Time/current zones for 60 A and 100 A fuse links
6. Typical oscillogram for large a.c. prospective
     current
7. Typical oscillogram for moderate a.c. prospective
     current
8. Measurement of prospective current
9. Typical time/current characteristics of cartridge
     fuse links of different current ratings
10. Measurement of recovery voltage
11. Computation of power factor

Requirements, ratings and tests for fuse links, fuse bases and carriers. Dimensions and time/current zones for fuse links. Type I-rated 240 V and 5 A to 45 A for replacement by domestic consumers; Type II-rated 415 V and 60 A, 80 A or 100 A for use by the supply authority in the incoming unit of domestic and similar premises.