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IEEE 1584 - 240V and under with 125KVA or less
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Author:  ronlow00 [ Tue Sep 22, 2015 5:41 am ]
Post subject:  IEEE 1584 - 240V and under with 125KVA or less

Can anyone point me to the specific article(s) or table(s) in IEEE 1584 which make the reference to 240V systems fed by trasnformers 125kVA or less?

Author:  stevenal [ Tue Sep 22, 2015 8:31 am ]
Post subject:  Re: IEEE 1584 - 240V and under with 125KVA or less

4.2, but the voltage in question is under 240, not 240.
9.3.2, but the voltage in question is 208, not 240.

Author:  ronlow00 [ Tue Sep 22, 2015 8:53 am ]
Post subject:  Re: IEEE 1584 - 240V and under with 125KVA or less

Thank you very much!

Author:  stevenal [ Mon Sep 28, 2015 8:51 am ]
Post subject:  Re: IEEE 1584 - 240V and under with 125KVA or less

Also should be less than 125 kVA.

Author:  Namgay Tshering [ Mon Sep 28, 2015 10:29 am ]
Post subject:  Re: IEEE 1584 - 240V and under with 125KVA or less

According to section 4.2, it states that "Equipment below 240 V need not be considered unless it involves at least one 125 kVA or larger low-impedance
transformer in its immediate power supply."
According to section 9.3.2, it states that "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."
Summary: Technically for 3-phase, 240 Volt system, Arc Flash study is required, regardless of the size of the service transformer. For 3-phase 208V, Arc Flash study is required for service transformer greater than 125 kVA. Since there is no utility transformer size 125 kVA, I use 112.5 kva as bench mark, but I have seen arc flash study performed on 3-phase 208V system fed by as small as 45 kVA transformer. I think it is good, there may not be a huge arc flash risk, but it addresses shock hazards and the employees get trained, creating awareness of arc flash.

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