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 Post subject: 2012 proposed low voltage table
PostPosted: Thu Feb 12, 2009 5:00 pm 
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Is this the most recent version?

So please help me understand: A 2500kVA 5.3% 277/480 three phase padmount transformer is feeding a panel board. The voltage puts me in column two. Energized work at the panel requires 40 cal/cm^2 from row 3 and note 6. Work at the padmount transformer terminals, however, requires 4 cal/cm^2, from row 4 and note 1. Does this order of magnitude change in IE make sense to anyone?


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PostPosted: Thu Feb 12, 2009 6:23 pm 
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stevenal wrote:
Is this the most recent version?

So please help me understand: A 2500kVA 5.3% 277/480 three phase padmount transformer is feeding a panel board. The voltage puts me in column two. Energized work at the panel requires 40 cal/cm^2 from row 3 and note 6. Work at the padmount transformer terminals, however, requires 4 cal/cm^2, from row 4 and note 1. Does this order of magnitude change in IE make sense to anyone?


Don't know what's up here, but our proposed tables do not match. I have attached the one that I have. Maybe someone else can shed some light on this.

Alan


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PostPosted: Fri Feb 13, 2009 10:25 am 
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Do the footnotes match?
I'm guessing my version is more recent, with the inclusion of network systems.


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PostPosted: Fri Feb 13, 2009 10:27 am 
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Alan's version is what was presented in the recent APPA Webinar. It treats panels the same as pad-mount transformers.

Where did your's come from Stevenal?

As far as I know, these are based on limited tests done by one utility. I understand that IEEE is making additional tests. The actual table that makes it into NESC-2012 may be quite different from either of these. We are not making recommendations based on the proposed table, but are making our clients aware of it.


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PostPosted: Fri Feb 13, 2009 2:04 pm 
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jghrist wrote:
Where did your's come from Stevenal?


APPA safety email list in September, prior to voting. Guess Alan's is more recent. Perhaps networks will be adressed outside of the table.

Know where I might find the footnotes or the whole *.ppt?


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PostPosted: Fri Feb 13, 2009 2:32 pm 
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You might be able to get it from APPA http://www.appanet.org/ . Since the Webinar was only open to APPA members or for a fee, I assume that it is copyrighted.


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PostPosted: Mon Oct 05, 2009 11:34 am 
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So I have the the proposed table which is out for comment. Any ideas on why a footnote describing 50 - 240 V testing is referenced from a cell in the 251 - 500 V column? From the last row.


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