It is currently Thu Jan 27, 2022 10:55 pm



Post new topic Reply to topic

Has your company / client used methods to reduce the prospective incident energy / arc flash hazard?
Yes
No
We are thinking about it
You may select 1 option

View results
Author Message
 Post subject: Reducing the Arc Flash Hazard / Prospective Incident Energy
PostPosted: Sun Mar 25, 2012 11:41 am 
Plasma Level
User avatar

Joined: Mon Sep 17, 2007 5:00 pm
Posts: 1637
Location: Scottsdale, Arizona
When performing an arc flash study, often one of the goals is to provide recommendations to reduce the incident energy below some value such as 8 cal/cm^2. This can sometimes be accomplished by methods such as changing protective device settings, maintenance switches, alternate protective schemes, remote operation etc. The list goes on.

This weeks question:

Has your company / client used methods to reduce the prospective incident energy / arc flash hazard?
  • Yes
  • No
  • We are thinking about it
As always, comments are encouraged.

_________________
Jim Phillips, P.E.
Brainfiller.com


Report this post
Top
 Profile Send private message  
Reply with quote  
 Post subject:
PostPosted: Sun Mar 25, 2012 3:01 pm 
Plasma Level
User avatar

Joined: Tue Oct 26, 2010 9:08 am
Posts: 2174
Location: North Carolina
One problem I've found with outside consultants is a tendency to just want to run the numbers and not even bother looking at the results. Simultaneously there's a tendency internally to just accept the results at face value in house and not pay any attention to the consequences of those decisions.


Report this post
Top
 Profile Send private message  
Reply with quote  
 Post subject:
PostPosted: Mon Mar 26, 2012 7:55 am 
Sparks Level

Joined: Thu Oct 18, 2007 7:10 pm
Posts: 263
Location: NW USA
I am an outside consultant that has spent that majority of arc flash study time working with system protection settings or distribution system configurations to achieve workable results. I agree with Paul that this is often overlooked.

An unexpected benefit of such work is consistency and reliability improvements achieved by normalizing equipment arrangements, sizing and protective settings. Prior to arc flash analysis it seemed any 'flavor of the week' was acceptable causing very mixed results.


Report this post
Top
 Profile Send private message  
Reply with quote  
 Post subject:
PostPosted: Mon Mar 26, 2012 11:01 am 
User avatar

Joined: Mon Jan 24, 2011 11:25 am
Posts: 38
Location: richmond, VA
We have 17 stone aggregate quarries and have strived to keep all arc flash hazards below 8 cal/cm2. At each location during the arc flash analysis, we have found one or more instances where we exceed 8 cal/cm2 and need to do some mitigation. We have changed fuse sizes and types, adjusted CB settings, split loads to multiple transformers etc. We have been successful in mitigating all but a select few, which enables our electrical techs to be safe in class II arc flash clothing. One extra benefit of the arc flash analysis work has been raising the awareness of all the techs and plant personel so that the amount of hot work that is performed is much much less then 10 years ago.


Report this post
Top
 Profile Send private message  
Reply with quote  
 Post subject:
PostPosted: Thu Jul 12, 2012 2:49 pm 
User avatar

Joined: Fri Jul 06, 2012 11:57 am
Posts: 8
Location: Fort Worth, Texas
We are working on arc flash mitigation. I am new to arc flash issues. Our toughest problems are old MLO switchboards. As I understand it, device settings mitigate load side only. Device settings help load side, but for many places the older breakers do not have enough adjustment and some switchboards have fused switches. Line side connections can only be mitigated by engineered mechanical methods? I am pushing for more engineered mitigation (barriers, etc.).


Report this post
Top
 Profile Send private message  
Reply with quote  
 Post subject:
PostPosted: Fri Jul 13, 2012 5:28 am 
Sparks Level

Joined: Tue Feb 24, 2009 7:05 am
Posts: 252
Ron Baggett wrote:
Line side connections can only be mitigated by engineered mechanical methods? I am pushing for more engineered mitigation (barriers, etc.).

Upstream adjustments.


Report this post
Top
 Profile Send private message  
Reply with quote  
 Post subject:
PostPosted: Fri Jul 13, 2012 6:22 am 
User avatar

Joined: Fri Jul 06, 2012 11:57 am
Posts: 8
Location: Fort Worth, Texas
Vincent B. wrote:
Upstream adjustments.

Yes. The specific application I had in mind was utility owned equipment upstream. If we are providing the upstream equipment (greater than 600 volt) we can address the arc flash mitigation methods upstream.


Report this post
Top
 Profile Send private message  
Reply with quote  
 Post subject:
PostPosted: Fri Jul 27, 2012 7:12 am 

Joined: Fri Jun 22, 2012 6:59 am
Posts: 8
Ron that would work. What would happen if the utility company changes their upstream distribution configuration? I dont believe there is a procedure requiring the provider to keep its client informed of any changes. This could affect your arc flash results in the future.


Report this post
Top
 Profile Send private message  
Reply with quote  
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 8 posts ] 

All times are UTC - 7 hours


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

Jump to:  
© 2022 Arcflash Forum / Brainfiller, Inc. | P.O. Box 12024 | Scottsdale, AZ 85267 USA | 800-874-8883