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ekstra   ara
 Post subject: Questions on How to Handle
PostPosted: Tue May 19, 2009 6:48 am 

Joined: Thu May 14, 2009 9:33 am
Posts: 6
Location: Alabama
I am doing my first arc flash hazard analysis and I am using EasyPower software. I have two questions:

1. I have an area in the plant that has 480VAC bus duct that has multiple fused disconnects attached. This bus duct is elevated above the floor about 12'. How do I show this in the software and how do I label this equipment?

2. I have an area that over the years instead of buying a mcc, the customer has just added more fused disconnects and combination starters. These are all mounted side by side and vary is sizes. The software covers how to handle a mcc, but I don't know how to handle this arrangement? How do I label (each device, in the general area?)?


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PostPosted: Tue May 19, 2009 7:06 am 
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Joined: Mon Jul 09, 2007 11:43 pm
Posts: 57
Location: Sheffield, England
[quote="levans"]
1. I have an area in the plant that has 480VAC bus duct that has multiple fused disconnects attached. This bus duct is elevated above the floor about 12'. How do I show this in the software and how do I label this equipment?

Hi, try this thread

http://www.arcflashforum.com/showthread.php?t=294&highlight=duct

If you use the search facility above and type in "bus duct". There are some other threads on bus ducts. I'll leave your second question for others but I would personally treat each item of equipment separately for labeling purposes.


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PostPosted: Tue May 19, 2009 7:39 am 

Joined: Thu Mar 19, 2009 9:40 am
Posts: 19
Location: Wi
Our main bus duct is 300' I've split that into 20 or 30 foot sections depending on the number of taps coming off and labled each bus with the distance....bus 3/ 20-40...
bus 3/ 40-60 etc. Each section is a node. Hope this makes sense.


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PostPosted: Sat Aug 29, 2009 4:55 am 
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Joined: Sun Aug 16, 2009 8:42 am
Posts: 184
Location: Lawrenceburg KY
I use the software every day. This is what I do but for every engineer a different way exist.

1) Model the busway and length.
a. You can do multiple lengths or model each section of busway.
b. Enter a bus between each section or groups of busway section.
c. Enter the bus tab type as Busway, and material.
2) Model the system the way it is.
a. Model the busplug's fused switch (or whatever) and enter fuse data.
b. Model the wire and conduit to the floor device.
c. Model the floor device say another fused switch , enter protective device data.
d. Model the wire and conduit to the load.
e. Model the load. Motor? or Heating or other for each device or use an MCC if there are multiple components on the load side. This will help you also with FLA and protective device design if needed.

If you place a bus before the fused switch on the floor that will reflect the load side AF. If you place a bus after the fused switch that is the Load side AF. I label the fused switch with the highest hazard of the two points. I also label downstream electrical control enclosures as needed. You can modeling the enclosure as a bus (node) or another protective device.

When in the bus data tab, select type panel and material type.

Hope this helps. It's the best way to accurately model your systems hazards. If you need more assistance let me know.


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PostPosted: Thu Sep 03, 2009 8:00 am 

Joined: Thu May 14, 2009 9:33 am
Posts: 6
Location: Alabama
Thank you for the information. Any chance that you might have an EasyPower project showing an example of this that you could send me?


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PostPosted: Mon Sep 14, 2009 3:41 am 
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Joined: Sun Aug 16, 2009 8:42 am
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Location: Lawrenceburg KY
levans,
I sent you a message off the forum.
Thanks


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PostPosted: Wed Oct 07, 2009 12:50 pm 

Joined: Mon Sep 24, 2007 7:10 pm
Posts: 16
Location: Washington
EasyPower example file

You may try asking EasyPower tech support your question. They have example onelines that show exactly how to model the busway. It involves grouping motors into 10' to 20' sections. There is no reason to model less than 10' due to very small impedance values that cause rounding errors. Give them a try.


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