It is currently Fri Jan 21, 2022 2:06 pm



Post new topic Reply to topic

When labeling bus duct, we apply/recommend that the arc flash labels be placed:
At the ends only
At specific intervals
At each bus plug
We do not use bus duct
Something else
You may select 1 option

View results
Author Message
 Post subject: Bus Duct Labeling
PostPosted: Sun Aug 28, 2011 3:45 pm 
Plasma Level
User avatar

Joined: Mon Sep 17, 2007 5:00 pm
Posts: 1635
Location: Scottsdale, Arizona
This topic seems to have many different opinions.

When labeling plug in bus duct, we apply/recommend that the arc flash labels be placed:
  • At the ends only
  • At specific intervals
  • At each bus plug
  • We do not use bus duct
  • Something else

_________________
Jim Phillips, P.E.
Brainfiller.com


Report this post
Top
 Profile Send private message  
Reply with quote  
 Post subject:
PostPosted: Wed Aug 31, 2011 5:33 am 

Joined: Fri Apr 01, 2011 6:06 am
Posts: 4
Location: Durham, NC
Bus Duct Protection

How many labels and how often is not something that we recommend too strongly. It is usually a matter of how each particular facility wants to manage things (and train).

The big mistake that we see is the labeling of each plug with calculation that depends on the response of the fuse/device contained in the plug being labeled. Such a label should be placed on the downstream equipment/disconnect.

The bus duct should be labeled on the basis of the upstream device that protects the duct. Is is recommended that the most distant end of the duct, with minimum available fault current be compared with the near end (least impedance) and the maximum available fault current. The entire duct should be labeled according to the worst-case energy between the two.


Report this post
Top
 Profile Send private message  
Reply with quote  
 Post subject:
PostPosted: Wed Aug 31, 2011 6:09 am 
Plasma Level

Joined: Mon Jun 02, 2008 11:58 am
Posts: 1103
Location: Charlotte, NC
I am curious of what the "Something else" answer was.


Report this post
Top
 Profile Send private message  
Reply with quote  
 Post subject:
PostPosted: Wed Aug 31, 2011 7:03 am 
Sparks Level

Joined: Wed Oct 29, 2008 6:06 am
Posts: 136
Location: Michigan
Something else = label at one end only.

We place an arc flash label on each bus tap box (or if no tap box then at the service). This label shows the highest IE on that bus.

Also, since the buses may be long, the tap box not always easily accessible and the standard AF label cannot be read from the ground, we place an additional label listing just the AFB, IE and PPE Level in large print on the tap box so that you don't have to actually maneuver a lift into the area just to read the label when the work is actually being done further down bus.


Report this post
Top
 Profile Send private message  
Reply with quote  
 Post subject:
PostPosted: Wed Aug 31, 2011 12:25 pm 

Joined: Fri Jun 17, 2011 3:18 am
Posts: 2
Location: PA
Is there really a need to place an Arc Flash label on a bus duct? Is there work that needs to be done on an energized duct? My company’s typical approach has been to ignore bus duct in arc flash calculations as it is not a switching device, and it would not be open when energized.


Report this post
Top
 Profile Send private message  
Reply with quote  
 Post subject:
PostPosted: Wed Aug 31, 2011 1:21 pm 
Plasma Level
User avatar

Joined: Mon Sep 17, 2007 5:00 pm
Posts: 1635
Location: Scottsdale, Arizona
David S. wrote:
Is there really a need to place an Arc Flash label on a bus duct? Is there work that needs to be done on an energized duct? My company’s typical approach has been to ignore bus duct in arc flash calculations as it is not a switching device, and it would not be open when energized.


For feeder duct, I would say no. The question was meant for plug in bus duct but it was not clear. I edited the original question to include "plug in".

_________________
Jim Phillips, P.E.
Brainfiller.com


Report this post
Top
 Profile Send private message  
Reply with quote  
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 6 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