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What is the largest bolted three phase short circuit current you have seen in an arc flash study?
Less than 25 kA
25 kA to 65 kA
Over 65 kA to 100 kA
Over 100 kA to 200 kA
Over 200 kA
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 Post subject: Largest Short Circuit Current in an Arc Flash Study
PostPosted: Sun Jun 03, 2012 3:26 pm 
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Joined: Mon Sep 17, 2007 5:00 pm
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Location: Scottsdale, Arizona
What is the largest bolted three-phase short circuit current you have seen in an arc flash study for systems 600 volts or less?
  • Less than 25 kA
  • 25 kA to 65 kA
  • Over 65 kA to 100 kA
  • Over 100 kA to 200 kA
  • Over 200 kA
Details such as the utility company and system configuration are always appreciated!

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PostPosted: Sun Jun 03, 2012 6:00 pm 
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Joined: Mon Jan 18, 2010 11:35 am
Posts: 551
Location: Wisconsin
Paralleled sources: both multiple backup generators and dual feeds with closed transition M-T-M configuration.


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PostPosted: Mon Jun 04, 2012 4:23 am 

Joined: Sat Jul 26, 2008 5:00 pm
Posts: 29
Con-Edison, New York's downtown LV network. Very high fault current.


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PostPosted: Mon Jun 04, 2012 10:02 am 
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Joined: Mon Jan 24, 2011 11:25 am
Posts: 38
Location: richmond, VA
I recently had utility contribution of 186,000 amps from a 500 kva transformer that was quite perplexing. After numerous phone calls and explanations how that did not seem possible the proper utility contribution was revised to 21,855.
If the utility company's information is suspect, keep asking for better information.


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PostPosted: Mon Jun 04, 2012 10:11 am 

Joined: Tue Jul 27, 2010 6:56 am
Posts: 5
Location: New York, NY
Con Es has very High Fault current of 150 kA or higher


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PostPosted: Mon Jun 04, 2012 12:50 pm 

Joined: Tue May 22, 2012 7:04 am
Posts: 6
Location: Mississauga, Ontario
280K at Copper Cliff Mines main service with all loads taken into account


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PostPosted: Wed Jun 13, 2012 7:28 am 
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Joined: Thu Jul 07, 2011 6:03 am
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Location: Netherlands
lsilecky wrote:
280K at Copper Cliff Mines main service with all loads taken into account


I'm sure you can get equipment that's rated against 300 kA, but would the 'special' prices that come along with it even be worth it for distribution?

Personally the scariest fault current I've found was around 150 kA, with equipment rated to about a third of that. The customer paralleled 4 transformers to equalize loading, not considering the increased fault levels. It had been that way for a while, too, thankfully without incident. Thankfully the transformers had the same winding configuration as well.


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PostPosted: Fri Jun 15, 2012 7:10 am 
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Location: Scottsdale, Arizona
Thanks for everyone's input on this one! This time the question of the week wasn't just a curiosity question to establish how people handle certain situations. This question was to help gauge how high the upper limit of the next edition of IEEE 1584 should be. Everyone's input was most helpful!

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PostPosted: Fri Jun 15, 2012 12:38 pm 

Joined: Mon Nov 29, 2010 5:02 am
Posts: 2
lsilecky wrote:
280K at Copper Cliff Mines main service with all loads taken into account[/quote
Where do you find a 200+ kA interrupting rating? That is quite unusually large.


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