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Largest Short Circuit Current in an Arc Flash Study
https://brainfiller.com/arcflashforum/viewtopic.php?f=33&t=2268		 Page 1 of 1
Author:  Jim Phillips (brainfiller) [ Sun Jun 03, 2012 3:26 pm ]
Post subject:  Largest Short Circuit Current in an Arc Flash Study
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!
Author:  JBD [ Sun Jun 03, 2012 6:00 pm ]
Post subject: 
Paralleled sources: both multiple backup generators and dual feeds with closed transition M-T-M configuration.
Author:  LLB [ Mon Jun 04, 2012 4:23 am ]
Post subject: 
Con-Edison, New York's downtown LV network. Very high fault current.
Author:  tish53 [ Mon Jun 04, 2012 10:02 am ]
Post subject: 
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.
Author:  Joseph [ Mon Jun 04, 2012 10:11 am ]
Post subject: 
Con Es has very High Fault current of 150 kA or higher
Author:  lsilecky [ Mon Jun 04, 2012 12:50 pm ]
Post subject: 
280K at Copper Cliff Mines main service with all loads taken into account
Author:  jvrielink [ Wed Jun 13, 2012 7:28 am ]
Post subject: 
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.
Author:  Jim Phillips (brainfiller) [ Fri Jun 15, 2012 7:10 am ]
Post subject: 
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!
Author:  LMorris [ Fri Jun 15, 2012 12:38 pm ]
Post subject: 
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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