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sharma.chinmayee
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Join Date: Dec 2012
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Short Circuit Withstand Current

12/17/2012 1:42 AM

What is the difference between Short circuit withstand current 40kA for 3second and 102kA for 1second. Which is better? Please explain.
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Joshi
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#1

Re: Short circuit withstand current

12/17/2012 2:21 AM

Read this: Protection, control and electrical devices - ABB
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PWSlack
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#2

Re: Short circuit withstand current

12/17/2012 3:12 AM

"Better"?

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sharma.chinmayee
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#3
In reply to #2

Re: Short circuit withstand current

12/17/2012 4:19 AM

I mean, which one should I take. Which is better to select as per the system safety???
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PWSlack
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#4
In reply to #3

Re: Short circuit withstand current

12/17/2012 4:55 AM

Which version of British Standard 7671 is in use there?

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electronick
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#5

Re: Short circuit withstand current

12/17/2012 5:21 AM

about the triple current in a third of the time!

the best one to choose? none

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Mushtaq Hussainh
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#6

Re: Short Circuit Withstand Current

12/17/2012 1:23 PM

Please estimate the let through energy during 3seconds with 40KA and 1second with 102Ka.

With these energies chech the cable withstanding energy and Motors. you will come to know which one damages the cable. Then you decide which one is better

Eng. Mushtaq Hussain

Hyderabad, India

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jack of all trades
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New Zealand - Member - Kiwi Popular Science - Weaponology - New Member Engineering Fields - Power Engineering - New Member Engineering Fields - Electrical Engineering - New Member

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#7

Re: Short Circuit Withstand Current

12/17/2012 2:25 PM

Homework or potential lawsuit for manslaughter?

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electricalexpert65
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#8

Re: Short Circuit Withstand Current

12/18/2012 8:58 AM

A breaker with a short time withstand of 102kA for 1 second would withstand 40kA for 6.5 seconds. So, on an apple to apple comparison (i.e.) on a 40kA withstand basis comparison, a 102kA for 1 second breaker is far more superior than a 40kA for 3 sec. breaker. But, that is only on technical parameters. Economically, a 40kA for 3sec. Breaker would be much cheaper than a 102kA for 1 sec. breaker.
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Anonymous Poster #1
#9
In reply to #8

Re: Short Circuit Withstand Current

12/18/2012 11:05 PM

electricalexpert65; Hi expert ,if you dont mind let me know your seconds calculation for the different KA ratings. What are all the factors that may can affect the effective tripping mechanisim in a practical situation.
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electronick
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#10
In reply to #9

Re: Short Circuit Withstand Current

12/20/2012 5:21 AM

one to consider are the electrodynamic forces in the s.c. the 102 kA would shake a lot more. the type of circuit before the point of the short circuit and cables.

there may have a few more, but only the person with knowledge of the site may access them.

hope it help.

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mashani
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#11

Re: Short Circuit Withstand Current

12/21/2012 4:35 AM

Please read first, don't just ask question such like this
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Users who posted comments:

Anonymous Poster (1); electricalexpert65 (1); electronick (2); jack of all trades (1); Joshi (1); mashani (1); Mushtaq Hussainh (1); PWSlack (2); sharma.chinmayee (1)

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