CURRENT CAPACITY AND SIZE OF CABLES FOR DISTRIBUTION TRANSFORMERS
Distribution transformer KVA
Full load current 400 volts side Amps
Size of PVC cable Aluminium sq.mm
1
1.44
4 x 25
10
14.40
4 x 4
25
39.10
4 x 10
50
72.2
4 x 16
75
108.3
3 1/2 x 35
100
144.4
3 1/2 x 50
200
289.3
3 1/2 x 185
300
433.0
3 1/2 x 300
500
800
3 1/2 x 500
CURRENT RATINGS FOR COPPER CONDUCTORS
Nominal cross-sectional area sq.mm
No and Dia of wires mm
250 - 440 Grade
650 - 1100V Grade
Twin amp
Three Core amp
Four Core amp
Twin amp
Three Core amp
Four Core amp
0.5
16/-200
10
9
8
11
9
9
0.75
24/-200
13
12
10
14
12
11
1.00
32/-200
15
13
12
15
13
12
1.5
48/-200
20
17
16
21
18
16
2.5
80/-200
27
24
22
28
24
22
4.0
128/-200
37
32
29
37
32
29
ECE and Chemical Equivalents
Substance
ECE
Atomic Weight
Valency
Chemical equivalent
Hydrogen
0.1040
1.008
1
1.008
Silver
1.1180
107.88
1
107.88
Nickel
0.3040
58.68
2
29.34
Aluminium
0.0938
26.97
3
9.03
Copper
0.3290
63.57
2
31.78
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