# Thread: Bus duct VD calculation

1. Senior Member
Join Date
Jul 2008
Location
nyc
Posts
243

## Bus duct VD calculation

I'm calculating VD on a bus duct.
The run is 400ft,
At 275ft there is a meter bank another one at 350ft and lastly one at 400ft.
With the various online calculators there are 2 options , distributed load & concentrated load.
I'm thinking that I should be working of distributed load whereas others think I should be using concentrated load to the 1st set of meter banks & segmented loads after that.
This makes a big difference as VD is halved if I can use the distributed load.
Which table should I use?

2. If you are being cost conscious, distributed is fine. Conservatively, youâ€™d use concentrated at end of run.

3. Moderator
Join Date
Jun 2003
Posts
6,874
to get the most accurate voltage drop, use the concentrated load and figure each section of bus duct individually, and add the results.

4. Senior Member
Join Date
Oct 2016
Location
Cleveland, Ohio
Posts
219
mcelweec

"With the various online calculators there are 2 options , distributed load & concentrated load."

Would you please post some "LINKS" or name the sites for a few of these calculators.

5. Originally Posted by MyCleveland
mcelweec

"With the various online calculators there are 2 options , distributed load & concentrated load."

Would you please post some "LINKS" or name the sites for a few of these calculators.
http://www.eaton.com/ecm/groups/publ.../ct_152882.xls

6. Senior Member
Join Date
Oct 2016
Location
Cleveland, Ohio
Posts
219
Thank you

7. Senior Member
Join Date
Oct 2016
Location
Cleveland, Ohio
Posts
219
Ingenieur

Have you used this program ?

If you understand the inputs.....can you explain difference between cell B1 & B13 ?

8. Originally Posted by MyCleveland
Ingenieur

Have you used this program ?

If you understand the inputs.....can you explain difference between cell B1 & B13 ?
'upsize' B13 (B10?) is if you want future expansion
say your load is currently 1000 (actual), and it will be 1250 (upsize) in 2 years after expansion
if no expansion or increase in load is planned actual = upsize

play with it
change inputs and see how it changes the results
Last edited by Ingenieur; 12-23-17 at 11:53 AM.

9. Senior Member
Join Date
Oct 2016
Location
Cleveland, Ohio
Posts
219
Ingenieur

Thanks again
I am tinkering...here is a rub. If B13 is not a table value (Standard Size), then everything collapses.

May I reach out again later ?

10. Senior Member
Join Date
Oct 2016
Location
Cleveland, Ohio
Posts
219
Concentrated vs Distributed....division by 2.
Guess I thought more options in the input selections were available.

#### Posting Permissions

• You may not post new threads
• You may not post replies
• You may not post attachments
• You may not edit your posts
•