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Theoretical Calculation of Current carrying capacity of Aluminium Busbars

I. 400A Aluminium Busbars with 1 Run of rectangular busbars :-

1. We use Electrical Conductivity Grade, WP/T6 (Range 1) – 56.5% of IACS

Aluminium Busbars.2 . Size of the Bus bars used for 400 A rating is 1RX50X10 mm.

Formula: I = 1.02 x A 0.5 x p

0.39 x Ө 0.61

[(1+α Ө)ρ] 0.5

Where:

I = Current in Amps

A = Cross sectional area of busbars in sq.mm = 50 X 10 =500sq.mm

p= Perimeter of bus bar in mm. = (50+10)2 =120 mm.

Ө = Temperature difference between conductor

and the ambient air at 35o C = 45 deg C

α = Resistance Temperature co-efficient of Aluminium at the ambient Temperature / degC = 0.00364

ρ = Resistivity of Aluminium at the ambient

Temperature-μΩcm = 3.133

I = 1.02 x 500 0.5 x 120 0.39 x 45 0.61

[(1+0.00364 x 45)3.133] 0.5

= 1504.62

1.909

= 788.17 Amps For calculation purpose parameters are considered for D50S – WP grade busbar, the conductivity of

which is of 55%. Where as we are using busbar of WP/T6 (Range 1) “Hindalco” busbar, theconductivity of which is of 56.5%.

Therefore % of increase in conductivity is 100 x 56.5 = 102.72%

55

Hence extra % of conductivity for the bus bars used = 2.72 %

Therefore the total current carrying capacity for WP/T6 (Range 1 )” Hindalco” busbars

= 788.17+2.72 x 788.17= 809.61 A

100

Current carrying capacity of single 50 x 10 mm. busbar is = 809.16A

Enclosure correction factor is applicable only for enclosures of Non Magnetic Materials.

However to be on safer side a correction factor of 0.8 can be considered.

Therefore current carrying capacity of 1RX50X10 mm. Al busbars = 809.61 X 0.8

=647.69 Amps.

Hence the Busbars provided by us (ie; 1Rx50x10mm) are more than adequate as per the above design

calculations.

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II. 600A Aluminium Busbars with 1 Run of rectangular busbars :-

1. We use Electrical Conductivity Grade, WP/T6 (Range 1) – 56.5% of IACS

Aluminium Busbars.2 . Size of the Bus bars used for 600 A rating is 1RX75X10 mm.

Formula: I = 1.02 x A 0.5 x p

0.39 x Ө 0.61

[(1+α Ө)ρ] 0.5

Where:

I = Current in Amps

A = Cross sectional area of busbars in sq.mm = 75 X 10 =750sq.mm

p= Perimeter of bus bar in mm. = (75+10)2 =170 mm.

Ө = Temperature difference between conductor

and the ambient air at 35o C = 45 deg C

α = Resistance Temperature co-efficient of Aluminium at the ambient Temperature / degC = 0.00364

ρ = Resistivity of Aluminium at the ambient

Temperature-μΩcm = 3.133

I = 1.02 x 750 0.5 x 170 0.39 x 45 0.61

[(1+0.00364 x 45)3.133] 0.5

= 2110.89

1.909

= 1105.76 Amps For calculation purpose parameters are considered for D50S – WP grade busbar, the conductivity of

which is of 55%. Where as we are using busbar of WP/T6 (Range 1) “Hindalco” busbar, theconductivity of which is of 56.5%.

Therefore % of increase in conductivity is 100 x 56.5 = 102.72%

55

Hence extra % of conductivity for the bus bars used = 2.72 %

Therefore the total current carrying capacity for WP/T6 (Range 1 )” Hindalco” busbars

= 1105.76+2.72 x 1105.76= 1135.84 A

100

Current carrying capacity of single 75 x 10 mm. busbar is = 1135.84 A

Enclosure correction factor is applicable only for enclosures of Non Magnetic Materials.

However to be on safer side a correction factor of 0.8 can be considered.

Therefore current carrying capacity of 1RX75X10 mm. Al busbars = 1135.84 X 0.8

=908.67 Amps.

Hence the Busbars provided by us (ie; 1Rx75x10mm) are more than adequate as per the above design

calculations.

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III. 800A Aluminium Busbars with 1 Run of rectangular busbars :-

1. We use Electrical Conductivity Grade, WP/T6 (Range 1) – 56.5% of IACS

Aluminium Busbars.

2 . Size of the Bus bars used for 800 A rating is 1RX100X10 mm.

Formula: I = 1.02 x A 0.5 x p

0.39 x Ө 0.61

[(1+α Ө)ρ] 0.5

Where:

I = Current in Amps

A = Cross sectional area of busbars in sq.mm = 100 X 10 =1000sq.mm

p= Perimeter of bus bar in mm. = (100+10)2 =220 mm.

Ө = Temperature difference between conductor

and the ambient air at 35o C = 45 deg C

α = Resistance Temperature co-efficient of

Aluminium at the ambient Temperature / degC = 0.00364

ρ = Resistivity of Aluminium at the ambientTemperature-μΩcm = 3.133

I = 1.02 x 1000 0.5 x 220 0.39 x 45 0.61

[(1+0.00364 x 45)3.133] 0.5

= 2695.29

1.909

= 1411.51 Amps For calculation purpose parameters are considered for D50S – WP grade busbar, the conductivity of

which is of 55%. Where as we are using busbar of WP/T6 (Range 1) “Hindalco” busbar, the

conductivity of which is of 56.5%.

Therefore % of increase in conductivity is 100 x 56.5 = 102.72%

55

Hence extra % of conductivity for the bus bars used = 2.72 %

Therefore the total current carrying capacity for WP/T6 (Range 1 )” Hindalco” busbars

= 1411.51+2.72 x 1411.51= 1449.91 A

100

Current carrying capacity of single 100 x 10 mm. busbar is = 1449.91 A

Enclosure correction factor is applicable only for enclosures of Non Magnetic Materials.

However to be on safer side a correction factor of 0.8 can be considered.

Therefore current carrying capacity of 1RX100X10 mm. Al busbars = 1449.91 X 0.8

=1159.93 Amps.

Hence the Busbars provided by us (ie; 1Rx100x10mm) are more than adequate as per the above

design calculations.

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IV. 1000A Aluminium Busbars with 1 Run of rectangular busbars :-

1. We use Electrical Conductivity Grade, WP/T6 (Range 1) – 56.5% of IACS

Aluminium Busbars.

2 . Size of the Bus bars used for 1000 A rating is 1RX125X10 mm.

Formula: I = 1.02 x A 0.5 x p

0.39 x Ө 0.61

[(1+α Ө)ρ] 0.5

Where:

I = Current in Amps

A = Cross sectional area of each busbar in sq.mm = 125 X 10 =1250sq.mm

p= Perimeter of bus bar in mm. = (125+10)2 = 270 mm.

Ө = Temperature difference between conductor

and the ambient air at 35o C = 45 deg C

α = Resistance Temperature co-efficient of Aluminium at the ambient Temperature / degC = 0.00364

ρ = Resistivity of Aluminium at the ambient

Temperature-μΩcm = 3.133

I = 1.02 x 1250 0.5 x 270 0.39 x 45 0.61

[(1+0.00364 x 45)3.133] 0.5

= 3263.97

1.909

= 1709.78 Amps

For calculation purpose parameters are considered for D50S – WP grade busbar, the conductivity of which is of 55%. Where as we are using busbar of WP/T6 (Range 1) “Hindalco” busbar, the

conductivity of which is of 56.5%.

Therefore % of increase in conductivity is 100 x 56.5 = 102.72%

55

Hence extra % of conductivity for the bus bars used = 2.72 %

Therefore the total current carrying capacity for WP/T6 (Range 1 )” Hindalco” busbars

= 1709.78 +2.72 x 1709.78= 1756.28 A

100

Current carrying capacity of single 125 x 10 mm. busbar is = 1756.28 A

Enclosure correction factor is applicable only for enclosures of Non Magnetic Materials.

However to be on safer side a correction factor of 0.8 can be considered.

Therefore current carrying capacity of 1RX125X10 mm. Al busbars = 1756.28 X 0.8

=1405.02 Amps.

Hence the Busbars provided by us (ie; 1Rx125x10mm) are more than adequate as per the above design

calculations.

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V. 1600A Aluminium Busbars with 2 Runs of rectangular busbars :-

1. We use Electrical Conductivity Grade, WP/T6 (Range 1) – 56.5% of IACS

Aluminium Busbars.

2 . Size of the Bus bars used for 1600 A rating is 2RX100X10 mm.

Formula: I = 1.02 x A 0.5 x p

0.39 x Ө 0.61

[(1+α Ө)ρ] 0.5

Where:

I = Current in Amps

A = Cross sectional area of busbars in sq.mm = 100 X 10 =1000sq.mm

p= Perimeter of bus bar in mm. = (100+10)2 =220 mm.

Ө = Temperature difference between conductor

and the ambient air at 35o C = 45 deg C

α = Resistance Temperature co-efficient of

Aluminium at the ambient Temperature / degC = 0.00364ρ = Resistivity of Aluminium at the ambient

Temperature-μΩcm = 3.133

I = 1.02 x 1000 0.5 x 220 0.39 x 45 0.61

[(1+0.00364 x 45)3.133] 0.5

= 2695.29

1.909

= 1411.51 Amps For calculation purpose parameters are considered for D50S – WP grade busbar, the conductivity of

which is of 55%. Where as we are using busbar of WP/T6 (Range 1) “Hindalco” busbar, the

conductivity of which is of 56.5%.

Therefore % of increase in conductivity is 100 x 56.5 = 102.72%

55

Hence extra % of conductivity for the bus bars used = 2.72 %

Therefore the total current carrying capacity for WP/T6 (Range 1 )” Hindalco” busbars

= 1411.51+2.72 x 1411.51= 1449.91 A

100

Current carrying capacity of single 100 x 10 mm. busbar is = 1449.91 ATherefore current carrying capacity of two busbars with air gap space equal to the Busbar thickness,

considering multiplying factor of 1.8, for 2 lamination = 1449.91 x 1.8

= 2609.84 Amps.

Enclosure correction factor is applicable only for enclosures of Non Magnetic Materials.

However to be on safer side a correction factor of 0.8 can be considered.

Therefore current carrying capacity of 2RX100X10 mm. Al busbars = 2609.84 X 0.8

=2087.87 Amps.

Hence the Busbars provided by us (ie; 2Rx100x10mm) are more than adequate as per the above

design calculations.

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VI. 3200A Aluminium Busbars with 4 Runs of rectangular busbars :-

1. We use Electrical Conductivity Grade, WP/T6 (Range 1) – 56.5% of IACS

Aluminium Busbars.

2 . Size of the Bus bars used for 3200 A rating is 4RX100X10 mm.

Formula: I = 1.02 x A 0.5 x p

0.39 x Ө 0.61

[(1+α Ө)ρ] 0.5

Where:

I = Current in Amps

A = Cross sectional area of busbars in sq.mm = 100 X 10 =1000sq.mm

p= Perimeter of bus bar in mm. = (100+10)2 =220 mm.

Ө = Temperature difference between conductor

and the ambient air at 35o C = 45 deg C

α = Resistance Temperature co-efficient of

Aluminium at the ambient Temperature / degC = 0.00364ρ = Resistivity of Aluminium at the ambient

Temperature-μΩcm = 3.133

I = 1.02 x 1000 0.5 x 220 0.39 x 45 0.61

[(1+0.00364 x 45)3.133] 0.5

= 2695.29

1.909

= 1411.51 Amps For calculation purpose parameters are considered for D50S – WP grade busbar, the conductivity of

which is of 55%. Where as we are using busbar of WP/T6 (Range 1) “Hindalco” busbar, the

conductivity of which is of 56.5%.

Therefore % of increase in conductivity is 100 x 56.5 = 102.72%

55

Hence extra % of conductivity for the bus bars used = 2.72 %

Therefore the total current carrying capacity for WP/T6 (Range 1 )” Hindalco” busbars

= 1411.51+2.72 x 1411.51= 1449.91 A

100

Current carrying capacity of single 100 x 10 mm. busbar is = 1449.91 A

Therefore current carrying capacity of four busbars with air gap space equal to the Busbar thickness,

considering multiplying factor of 3.2, for 4 lamination = 1449.91 x 3.2

= 4639.71 Amps.

Enclosure correction factor is applicable only for enclosures of Non Magnetic Materials.

However to be on safer side a correction factor of 0.8 can be considered.

Therefore current carrying capacity of 4RX100X10 mm. Al busbars = 4639.71 X 0.8

=3711.77 Amps.

Hence the Busbars provided by us (ie; 4Rx100x10mm) are more than adequate as per the above

design calculations.

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VII. 4000A Aluminium Busbars with 4 Runs of rectangular busbars :-

1. We use Electrical Conductivity Grade, WP/T6 (Range 1) – 56.5% of IACS

Aluminium Busbars.

2 . Size of the Bus bars used for 4000 A rating is 4RX125X10 mm.

Formula: I = 1.02 x A 0.5 x p

0.39 x Ө 0.61

[(1+α Ө)ρ] 0.5

Where:

I = Current in Amps

A = Cross sectional area of busbars in sq.mm = 125 X 10 =1250sq.mm

p= Perimeter of bus bar in mm. = (125+10)2 =270 mm.

Ө = Temperature difference between conductor

and the ambient air at 35o C = 45 deg C

α = Resistance Temperature co-efficient of

Aluminium at the ambient Temperature / degC = 0.00364

ρ = Resistivity of Aluminium at the ambientTemperature-μΩcm = 3.133

I = 1.02 x 1250 0.5 x 270 0.39 x 45 0.61

[(1+0.00364 x 45)3.133] 0.5

= 3263.97

1.909

= 1709.78 Amps For calculation purpose parameters are considered for D50S – WP grade busbar, the conductivity of

which is of 55%. Where as we are using busbar of WP/T6 (Range 1) “Hindalco” busbar, the

conductivity of which is of 56.5%.

Therefore % of increase in conductivity is 100 x 56.5 = 102.72%

55

Hence extra % of conductivity for the bus bars used = 2.72 %

Therefore the total current carrying capacity for WP/T6 (Range 1 )” Hindalco” busbars

= 1709.78 +2.72 x 1709.78= 1756.29 A

100

Current carrying capacity of single 125 x 10 mm. busbar is = 1756.29 A

Therefore current carrying capacity of four busbars with air gap space equal to the Busbar thickness,

considering multiplying factor of 3.2, for 4 lamination = 1756.29 x 3.2

= 5620.13 Amps.

Enclosure correction factor is applicable only for enclosures of Non Magnetic Materials.

However to be on safer side a correction factor of 0.8 can be considered.

Therefore current carrying capacity of 4RX125X10 mm. Al busbars = 5620.13 X 0.8

=4496.10 Amps.

Hence the Busbars provided by us (ie; 4Rx125x10mm) are more than adequate as per the above

design calculations.

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VIII. 6000A Aluminium Busbars with 4 Runs of rectangular busbars :-

1. We use Electrical Conductivity Grade, WP/T6 (Range 1) – 56.5% of IACS

Aluminium Busbars.

2 . Size of the Bus bars used for 6000 A rating is 4RX200X10 mm.Formula:

I = 1.02 x A 0.5 x p0.39 x Ө 0.61

[(1+α Ө)ρ] 0.5

Where:

I = Current in Amps

A = Cross sectional area of each busbar in sq.mm = 200 X 10 = 2000sq.mm

p= Perimeter of bus bar in mm. = (200+10)2 = 420 mm.

Ө = Temperature difference between conductor

and the ambient air at 35o C = 45 deg C

α = Resistance Temperature co-efficient of

Aluminium at the ambient Temperature / degC = 0.00364

ρ = Resistivity of Aluminium at the ambientTemperature-μΩcm = 3.133

I = 1.02 x 2000 0.5 x 420 0.39 x 45 0.61

[(1+0.00364 x 45)3.133] 0.5

= 4905.03

1.909

= 2569.42 Amps For calculation purpose parameters are considered for D50S – WP grade busbar, the conductivity of

which is of 55%. Where as we are using busbar of WP/T6 (Range 1) “Hindalco” busbar, the

conductivity of which is of 56.5%.

Therefore % of increase in conductivity is 100 x 56.5 = 102.72%

55

Hence extra % of conductivity for the bus bars used = 2.72 %

Therefore the total current carrying capacity for WP/T6 (Range 1 )” Hindalco” busbars

= 2569.42 +2.72 x 2569.42 = 2639.30 A

100

Current carrying capacity of single 200 x 10 mm. busbar is = 2639.30 A

Therefore current carrying capacity of Four busbars with air gap space equal to the Busbar thickness,

considering multiplying factor of 3.2 for 4 laminations = 2639.30 X 3.2

= 8445.79 Amps. Enclosure correction factor is applicable only for enclosures of Non Magnetic Materials.

However to be on safer side a correction factor of 0.8 can be considered.

Therefore current carrying capacity of 4RX200X10 mm. Al busbars =8445.79 X 0.8

= 6756.62 Amps. Hence the Busbars provided by us (ie; 4Rx200x10mm) are adequate as per the above design

calculations.