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| 208V equipment fed from 750kva 600/208V transformer https://brainfiller.com/arcflashforum/viewtopic.php?f=23&t=316 |
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| Author: | J.T [ Fri Jan 30, 2009 10:42 am ] |
| Post subject: | 208V equipment fed from 750kva 600/208V transformer |
I am a new member. Please let me post a question. IEEE 1584 states:"Equipment below 240v need not be considered unless it involves at least one 125kva or larger low impedance transformer in its IMMEDIATE supply" My case: 750kVA 600/208-120V 7.1% transformer supplys 208V switchboard A. Switchboard A supplys 208V panel B via cables, and panel B supplys another 208V panel C via cables. I need to do arc flash analysis for switch board A based on IEEE 1584. Do I need to do arc flash analysis for panel B and C? Or just label panel B and C according to NFPA 70 table 130.7(C)(9)(a)? I do not think the 750kva transformer is immediate supply to panel B. C. Thanks! |
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| Author: | RECS [ Mon Apr 20, 2009 8:37 pm ] |
| Post subject: | |
I don't think that the transformer is Panel B or C immediate power supply. I understand that the calculation is not necessary. |
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| Author: | stevenal [ Tue Apr 21, 2009 1:13 pm ] |
| Post subject: | |
The same standard says "The arc-flash hazard need only be considered for large 208 V systems: systems fed by transformers smaller than 125 kVA should not be a concern." No "immediate" qualifier there. Also note that NFPA avoids the "immediate" qualifier. Also see [url="http://www.arcflashforum.com/showthread.php?t=324"]http://www.arcflashforum.com/showthread.php?t=324[/url] |
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| Author: | haze10 [ Tue Apr 21, 2009 4:30 pm ] |
| Post subject: | |
YOU don't have to list the the HRC Task Matrix. Since it is outside the analysis,, you can just list a single HRC of 1 or 0 for all tasks. |
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