Arc-Flash 4800V

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Mike01

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On a 4800V system with 15Kv class gear when running a arc-flash study based on IEEE-1584-2002, the gap distance for 15Kv gear is 153mm as opposed to 102mm for 5Kv class gear, however when you run the serino of a 4800V system on 5Kv gear with 153mm gap distance the category increases 1 class in most cases why is this if the clearing time does not change and the available fault current remains the same??:confused:
 
Mike01 said:
On a 4800V system with 15Kv class gear when running a arc-flash study based on IEEE-1584-2002, the gap distance for 15Kv gear is 153mm as opposed to 102mm for 5Kv class gear, however when you run the serino of a 4800V system on 5Kv gear with 153mm gap distance the category increases 1 class in most cases why is this if the clearing time does not change and the available fault current remains the same??:confused:

The distance of the gap.

Just like in arc welding, with everything else constant the smaller the gap the more intense the arc.
 
Mike01 said:
On a 4800V system with 15Kv class gear when running a arc-flash study based on IEEE-1584-2002, the gap distance for 15Kv gear is 153mm as opposed to 102mm for 5Kv class gear, however when you run the serino of a 4800V system on 5Kv gear with 153mm gap distance the category increases 1 class in most cases why is this if the clearing time does not change and the available fault current remains the same??:confused:
Mike
Put your data up. I did it guessing at the info and the results were the same.
Eq. Class
Cond Gap
Work Dist
Avail 3 phase fault
Voltage
Arc Duration
Arc duration at reduced current
How are you getting the available 3 phse fault?
 
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