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 Post subject: IEEE 1584 - 240V and under with 125KVA or less
PostPosted: Tue Sep 22, 2015 5:41 am 
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Location: St. Paul, MN
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?


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 Post subject: Re: IEEE 1584 - 240V and under with 125KVA or less
PostPosted: Tue Sep 22, 2015 8:31 am 
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4.2, but the voltage in question is under 240, not 240.
9.3.2, but the voltage in question is 208, not 240.


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 Post subject: Re: IEEE 1584 - 240V and under with 125KVA or less
PostPosted: Tue Sep 22, 2015 8:53 am 
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Location: St. Paul, MN
Thank you very much!


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 Post subject: Re: IEEE 1584 - 240V and under with 125KVA or less
PostPosted: Mon Sep 28, 2015 8:51 am 
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Also should be less than 125 kVA.


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