The following table is based on the information given in the I.E.E. Regulations 12^th Edition 1950 table 21 Approximate sixes of fuse elements composed of tinned copper for use in semi enclosed fuses. The figures are an approximate guide only the current at which the fuse will blow will depend upon the construction of the fuse holder inn which wire is used.

S.W.G

Current rating of Fuse in Amperes

Approximate fusing Current

40

1.5

3

39

2.5

4

38

3

5

37

3.5

6

36

4.5

7

35

5

8

34

5.5

9

33

6

10

32

7

11

31

8

12

30

8.5

13

29

10

16

28

12

18

27

13

23

26

14

28

25

15

30

24

17

33

23

20

38

22

24

48

21

29

58

20

34

70

19

38

81

18

45

106

17

65

135

16

73

166

15

78

197

14

102

230

13

130

295

H.G. FUSE RATINGS FOR TRANSFORMERS

Capacity of transformer

 in KVA

H.T. Voltage

Size of T.C. fuse

wire in S.W.g

Horn gap length

in mm (inches)

1500

33 KV

2 x20

385 (15)

3000/3150

-

20

-

1500/1600

-

21

-

1000

-

22

-

750

-

23

-

500

-

26

-

500

11 KV

20

205 (8)

250

-

23

-

100

-

33

-

75

-

33

-

63

-

33

-

50

-

33

-

25

-

38

-