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| High Incident Energy on 208/120 V Panels https://brainfiller.com/arcflashforum/viewtopic.php?f=23&t=1632 |
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| Author: | Vica1ME [ Thu Mar 24, 2011 3:16 pm ] |
| Post subject: | High Incident Energy on 208/120 V Panels |
Can anyone give me an idea, why I would be receiving a higher incident energy on the 208/120 V secondary? On the 480/277 panels I have a lot of Category 2. On the 208/120, I have a lot of 3's and a couple 4's. The initial transformer is 2500 kva with 6% impedance. The second transformer is 750 VA, I'm not sure of the impedence. Any help would be greatly appreciated. |
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| Author: | Jim Phillips (brainfiller) [ Sun Mar 27, 2011 5:48 pm ] |
| Post subject: | |
Incident Energy Vica1ME wrote: Can anyone give me an idea, why I would be receiving a higher incident energy on the 208/120 V secondary? On the 480/277 panels I have a lot of Category 2. On the 208/120, I have a lot of 3's and a couple 4's. The initial transformer is 2500 kva with 6% impedance. The second transformer is 750 VA, I'm not sure of the impedence. Any help would be greatly appreciated.
It sounds like the problem might be with a long clearing time by the transformer primary device. Check your Category 3's and 4's and see what protective device is being referenced (i.e. primary?) and then check to see what clearing time the software is using. Most programs have tables that list all of this information. |
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