Busbar sizing

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jimk7525

New member
Hi,
I was wondering if there was a calculation to size a busbar according to wire size. I am trying to solve a calculation that doesn't give me any information to educate myself on this and so have turned to asking the forum. Thank you in advance. James
 
P

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
jimk7525 said:
Hi,
I was wondering if there was a calculation to size a busbar according to wire size. I am trying to solve a calculation that doesn't give me any information to educate myself on this and so have turned to asking the forum. Thank you in advance. James
Click to expand...

Have you considered checking the web site of the manufacturer of the bus bar?
 
ohmhead

ohmhead

Senior Member
Location
ORLANDO FLA
jimk7525 said:
Hi,
I was wondering if there was a calculation to size a busbar according to wire size. I am trying to solve a calculation that doesn't give me any information to educate myself on this and so have turned to asking the forum. Thank you in advance. James
Click to expand...

Well try this !

Bus bar ampere capacity

thickness x width= square inches


sq in x 1000 = amps per sq in of copper

sq in x700 = amps per sq in of aluminum


If the bar was 1/2 thick and 6 inches wide then

.5x6=3 then 3 x1000 = 3000 amps that how its done




A bus bar 1/8 thick and 1 wide lets change that to circular mils .

.7854 is area of sq inch



1/8 =.125 x 1000 = 125 mils

1 x 1000 = 1000 mils

125 mils x 1000 = 125,000 square mils

cm = 125,000 sq mil/.7854= 159,155cm

Now go to your NEC code book tables and find the closest cm this would be a
3/0 = 167,800 cm
 
chris kennedy

chris kennedy

Senior Member
Location
Miami Fla.
Occupation
60 yr old tool twisting electrician
ohmhead said:
It was a long time ago Chris in 1970 when you took the test they made you learn about sizing bus bars it was on the JR test .

That Orlando was a joke kinda !

So how are you southern boys doing !
Click to expand...

I checked your math with the AEH and your spot-on.

We southern boys are crazy busy.:thumbsup:
 
ohmhead

ohmhead

Senior Member
Location
ORLANDO FLA
chris kennedy said:
I checked your math with the AEH and your spot-on.

We southern boys are crazy busy.:thumbsup:
Click to expand...


Well the central florida boys are holding up but theres not much going on iam doing a hospital now just finishing it up and going to start a new job next month downtown . Its real hot i think its hotter this year then the last great i get to start underground in July the worst month to be outside . Good to see your still checking my math iam getting old now so i might be off a few amps . hee hee
 
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