ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals

ECN Shout Chat
Top Posters(30 Days)
Admin 19
Recent Posts
Anyone hiring inspectors?
by HotLine1. 03/27/17 08:03 AM
Old decora style outlets
by Admin. 03/25/17 11:40 AM
ESA Arc flash course
by TheShockDoctors. 03/24/17 10:15 AM
fuse rejectors
by HotLine1. 03/24/17 07:53 AM
Another Forum Update
by Admin. 03/22/17 03:04 PM
New in the Gallery:
SE cable question
Popular Topics(Views)
231,626 Are you busy
166,455 Re: Forum
160,717 Need opinion
Who's Online Now
0 registered members (), 68 guests, and 11 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate This Thread
#163165 - 05/02/07 10:42 PM Bussbar ampacities  
OreElect  Offline
Member
Joined: Mar 2004
Posts: 98
Salem,Oregon.USA
Hi all.
I recently had a question of what size buss bar for a 1200 amp load 1000 feet away.
Besides buss bar manufacturers sizing charts ,any one have any rule of thumb to size? I found no info in nec. I`ll spend some time in AE Handbook and see what I can come up with.


Work Gear for Electricians and the Trades

#163171 - 05/03/07 05:57 AM Re: Bussbar ampacities [Re: OreElect]  
jdo1942  Offline
Junior Member
Joined: Nov 2005
Posts: 31
st. louis, mo. usa
If you are looking for a quick rule like after a 100 ft you increase the wire size, that just doesn't work with buss bars. You have to depend on voltage drop formulas that will tell you the voltage drop. You can't just up size buss bars.


#163176 - 05/03/07 09:41 AM Re: Bussbar ampacities [Re: jdo1942]  
Last Leg  Offline
Member
Joined: May 2005
Posts: 41
Houston, Texas
Somebody correct my if I am wrong...
Votage drop is pretty easy to calculate (the resistance meathod is more accurate.. but this is close) 2 x the length x amperage (load, not nominal amps) x constant (=12 for copper & 18 for aluminum) / (diveded by) cm of the wire (larger wire cm is the wire size). Size the wire for voltage drop; the bus bar 'length' is so short, you shoul be able to just use the standard rating for that amperage.



Member Spotlight
Posts: 165
Joined: March 2007
Show All Member Profiles 
Featured:

2017 NEC and Related
2017 NEC
Now Available!

Shout Box
Powered by UBB.threads™ PHP Forum Software 7.6.0
Page Time: 0.014s Queries: 15 (0.004s) Memory: 0.7495 MB (Peak: 0.8734 MB) Zlib enabled. Server Time: 2017-03-28 06:21:37 UTC