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Question
```How to calculate busbar size & what is the procedure we
make for determine that?```
Question Submitted By :: Electrical-Engineering
I also faced this Question!!     Answer Posted By

# 1
Generally current carrying capacity of Al. is 0.8A per
sqmm and Copper is 1.6A per Sqmm.

Suppose we need bus bar for 630A, and we are going with
Aluminium bus bar

= 80*10*.8=640A
where 80*10 is size if bus bar usually available is the
market.
so we can use 80x10sqmm al. busbar per phase for 630A.

for TPN- (3.5)x80x10

If we are going with Copper bus bar
than we will use = 40x10sqmm per phase

= 40x10x1.6=640A
where 40*10 is size if bus bar usually available is the
market.
so we can use 40x10sqmm copper busbar per phase for 630A.

for TPN- (3.5)x40x10

 Is This Answer Correct ? 88 Yes 12 No
Sujata Wagh

# 2
The busbar size will be determined by the total loads
connected to the bus.This will require a comprehensive
study of nature of loads plus the surroundings of place.
The general procedure will be such that the operating
parameters don't voilate the maximum safety limits of the
bus.

 Is This Answer Correct ? 120 Yes 52 No
Ashraf Majid

# 3
to calculate bus bar size normally for copper 1 sqmm =1.3 A
for aluminium 1 sqmm =0.8 Amps

 Is This Answer Correct ? 83 Yes 28 No
Kajajohn

# 4
i want to add in vijay answer that the qulity of copper also
depend on amper rating of coper bar

 Is This Answer Correct ? 45 Yes 16 No
Akmal

# 5
The bus bar size normally for copper 1sqmm=1.3Am and
aluminium is 1sqmm=0.8Amp

 Is This Answer Correct ? 42 Yes 15 No
Nikhan

# 6
current density= .8 amp/sqmm.that does mean 1sqmm can carry
0.8 amp current .if sisze of busbar is 100mmx 10 mm then it
can carry 800 amp.

 Is This Answer Correct ? 44 Yes 18 No
Jaydev Jena

# 7
busbar sizes can not be calculated only from overall size.
there are various derating factors like arrangment of
busbar, nos of busbar, spacing, enclouser size, ventilation
in room, temp rise, skin effect, proximity effect etc.
which need to be consider while designing the busbar.

 Is This Answer Correct ? 36 Yes 12 No
Bhavin Shah

# 8
can you give any example at any parameters?
 Is This Answer Correct ? 56 Yes 34 No
Balakrishnan

# 9
Generally current carrying capacity of Al. is 0.8A per
sqmm and Copper is 1.6A per Sqmm.

Suppose we need bus bar for 630A, and we are going with
Aluminium bus bar

= 80*10*.8=640A
where 80*10 is size if bus bar usually available is the
market.
so we can use 80x10sqmm al. busbar per phase for 630A.

for TPN- (3.5)x80x10

If we are going with Copper bus bar
than we will use = 40x10sqmm per phase

= 40x10x1.6=640A
where 40*10 is size if bus bar usually available is the
market.
so we can use 40x10sqmm copper busbar per phase for 630A.

for TPN- (3.5)x40x10

 Is This Answer Correct ? 21 Yes 6 No
Waves

# 10
Usually busbar sizes selection depends mainly on two
factors. Which is current + temperature. The size which you
are going to select must carry the current you need and
must not create much heat which excess the limits.

Our formula , we use 1.5 A / 1 sqmm.

 Is This Answer Correct ? 19 Yes 5 No
Khan

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