It is currently Sat Jul 02, 2022 11:21 pm

Author Message

 Post subject: Conversion error in CSA Z462-08 Annex D?Posted: Wed Mar 04, 2009 7:10 am
 Sparks Level

Joined: Tue Feb 24, 2009 7:05 am
Posts: 252
Hello there,

In equation D.5.2(a) of Annex D of CSA Z462-08, the exponent of D_A is -0.9246. In equation D.5.1(a) of Annex D of NFPA 70E 2009, it's -1.9593. The two following sample calculations give the same Incident Energy given the same input data.

All this seem OK, until you try some other value of D_A with both equations. Then you don't get the same results.
Somebody fuddled with the exponent of D_A so the sample calculation worked out OK, but you can't do that as all other values of D_A won't give you the same results.

I propose the following to replace equation D.5.2(a) of Annex D of CSA Z462-08:
E_MA = 5271 x 25.4^1.9593 x D_A^-1.9593 x t_A x [0.0016F^2 - 0.0076F + 0.8938]
which could be simplified in
E_MA = 2981000 x D_A^-1.9593 x t_A x [0.0016F^2 - 0.0076F + 0.8938]

Also, in CSA Z462-08, the definition of D_A for equation D.5.2(a) says it's in inch, when it should be in mm.

The same conversion mistake has been made in equation D.5.3(a) of CSA Z462-08. I propose the following to replace equation D.5.3(a) of Annex D of CSA Z462-08 (once simplified):
E_MB = 587460 x D_A^-1.4378 x t_A x [0.0093F^2 - 0.3453F + 5.9675]

Any comments on this?
To who should I report this?

Top

 Post subject: Posted: Wed Mar 04, 2009 7:34 am
 Sparks Level

Joined: Tue Feb 24, 2009 7:05 am
Posts: 252
A typo this time...

In D.7.3 of Annex D of CSA Z462-08, the definition for K says:
Quote:
K = -0.153 for open-air arcs
K = 0.097 for arcs in a box

In D.7.2 of Annex D of NFPA 70E 2009, the same definitions for K says:
Quote:
K = -0.153 for open-air arcs; -0.097 for arcs-in-a-box

I don't have IEEE 1584 to compare what that standard says.

To who should I report this?
Thanks.

Top

 Post subject: Posted: Thu Mar 05, 2009 11:45 am
 Arc Level

Joined: Tue Jan 13, 2009 5:00 pm
Posts: 584
1584 agrees with 70E.

Top

 Post subject: Posted: Thu Mar 05, 2009 11:57 am
 Sparks Level

Joined: Tue Feb 24, 2009 7:05 am
Posts: 252
So CSA Z462-08 is in need of a correction.

I'll look into how to do this.

Top

 Post subject: Posted: Sun Mar 22, 2009 9:26 am
 Sparks Level

Joined: Sun Sep 23, 2007 5:00 pm
Posts: 129
Location: Calgary, Alberta, Canada
Vincent:

I am on the CSA Z462 Technical Committee, next meeting is in Regina, April 1-2.

We are treating all comments as formal requests for clarification, we need this to happen.

Can you email me your comments so I can follow up formally

Regards;
Terry Becker
http://www.esps.ca
[email protected]

Top

 Post subject: Posted: Mon Mar 23, 2009 5:27 am
 Sparks Level

Joined: Tue Feb 24, 2009 7:05 am
Posts: 252
Sure Terry. I'll do it so we get a better CSA Z462 in the end, one we can trust.

Top

 Display posts from previous: All posts1 day7 days2 weeks1 month3 months6 months1 year Sort by AuthorPost timeSubject AscendingDescending
 Page 1 of 1 [ 6 posts ]

 All times are UTC - 7 hours

 You cannot post new topics in this forumYou cannot reply to topics in this forumYou cannot edit your posts in this forumYou cannot delete your posts in this forumYou cannot post attachments in this forum

 Jump to:  Select a forum ------------------ Forum Library / Articles The Lounge    Question of the Week - What Do You Think?    Arcflashforum.com Feedback and Announcements    Off Topic Discussions    News in Electrical Safety Arc Flash and Electrical Safety    General Discussion    Electrical Safety Practices    Equipment to Reduce Arc Flash Dangers    Personal Protective Equipment (PPE) Arc Flash Studies    General Discussion    Arc Flash Labels    Software for Arc Flash Studies    System Modeling and Calculations    NEW! Electrode Configuration Library – 2018 IEEE 1584 Codes and Standards    CSA Z462 Workplace Electrical Safety    EAWR Electricity at Work Regulations, HSE - Europe    OSHA CFR Title 29    IEEE 1584 - Arc-Flash Hazard Calculations    NFPA 70 - National Electrical Code - NEC (R)    NESC - ANSI C2 - National Electrical Safety Code    NFPA 70E - Electrical Safety in the Workplace    2015 NFPA 70E Share It Here    Arc Flash Photos    Your Stories    What's Wrong Here? by Joe Tedesco
© 2022 Arcflash Forum / Brainfiller, Inc. | P.O. Box 12024 | Scottsdale, AZ 85267 USA | 800-874-8883