Bus bar Calculation

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engrkira

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Help me for the bus bar calculation:

Given a 1.5 MVA, 3 phase, 400 V. What would be the size of my busbar (copper material)?

Just comment if you need more details other than these.

Thank you.
 
engrkira said:
Help me for the bus bar calculation:

Given a 1.5 MVA, 3 phase, 400 V. What would be the size of my busbar (copper material)?

Just comment if you need more details other than these.

Thank you.
Click to expand...
The cross sectional area required for a specific current rating is something typically defined in the electrical code or design standards that you need to adhere to in the location where it is being installed. Even then, it's not an easy thing that you just punch into a calculator, there are a lot of factors that go into it. Off the top of my head, X-sectional area, shape, number of parallel bars (you will need 3750A total, won't be one bar), spacing, ambient temperature, allowable temperature rise, air flow, fault bracing, etc. etc. It's an art form as much as it is an engineering question.

No offense intended but bottom line, if you have to ask an anonymous web forum, you might not be the right person for the job.
 
I agree with Jraef, of course [even if he forgot to divide by 1.732:slaphead: the current is still elevated].
You may get an information not a design. An experimented engineer-or company-could solve this problem.
You need a lot of other parameters as ambient temperature, short-circuit presumable current, enclosure type and dimensions, openings and other.
For a rough information see[for instance]:
IEC 60865-1 Short-circuit currents –Calculation of effects
http://copperalliance.org.uk/docs/l.../copper-for-busbars-all-sections.pdf?sfvrsn=2
ch.2.0 Current-Carrying Capacity of Busbars
 
Sorry sir but I am still a student and we do need to design a building requiring bus bars in switch gears so I don't have that much idea in it but nevertheless thank you so much.

I think I got enough information with all of you. I need some derating factors then applying the rule of thumb and finding the correct size based on what the results came up.

Thanks again guys
 
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