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agni mohanty
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Join Date: Dec 2009
Posts: 10

Cables vs. Bus Ducts

12/15/2009 11:47 PM

Can you plz suggest me what is the advantage of using cable instead of busduct & the vice-versa
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Anonymous Poster
#1

Re: bus duct

12/16/2009 3:40 AM

Busducts are mostly prefered between transformer LT to SWGR (located nearer) which handles the heavy current and also to reduce the posibility of fault. For the same case you can also use cable but the number of runs will be more and feasibility of termination is also difficult.

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P.Deenadayalan
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kvsubramanyam
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Location: Hyderabad, India
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#2

Re: Cables vs. Bus Ducts

12/16/2009 10:48 PM

Practicality! Suppose you have 10 motor control panels at one place better you go for bus duct to give mains power to all panels; so you can avoid a Sub-DB. Now-a-days receptacle bus ducts are available in the market (ready-made). I am working for a battery company. We have hundreds of battery chargers. So for such application bus duct for every 10 chargers is the best solution.

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andreY
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Join Date: Nov 2009
Posts: 14
#3

Re: Cables vs. Bus Ducts

12/17/2009 2:10 AM

Could you pls tell me what is advantage of busduct from Trafo LV to gearbox? I always use cables and cannot see any negative points - flexible, easy to install , no troubles from operation/maintenance. with duct - image that transformer is installed 20 cm left or right from designed position. what will you do with busduct? discussed with Siemens last week this question - suggestion to order duct when trans and gearbox are already on their places, but it will take you a lot of time. cable is cheaper besided of all.

for me it is very depend on your own previous experience - no big advantages/disadvantages for both.
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electricalexpert65
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Join Date: Oct 2009
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#4

Re: Cables vs. Bus Ducts

12/18/2009 8:47 AM
Sr no

Issue

Cable

Busbar

1 Number of circuits One circuit per floor. Hence for a 20-floor building, you need 20 circuits. Just one circuit can cover all floors.
2 Main Switchboard Need 1 outgoing for each circuit. Hence 20 nos. MCCB outgoings. Higher cost and larger space requirement in electrical room Need only 1 outgoing for each riser.

Lower cost and size of main panel.

3 Shaft Size Using 4 core cables, and considering 1 cable per feeder, you need 20 cables on the lowest floor. Large space required for cables/ cable tray. Typical size of 1600A riser is 185mm x 180mm. Leads to big savings on riser shaft size, and hence

more usable floor area on every floor.

4 Fire & safety The high concentration of insulating materials used in cables and conductors involves a very high level of combustive energy The volume of insulating materials used in trunking is reduced to a minimum so combustive energy is considerably lower than cables. The insulating materials used do not release corrosive or toxic gases in the event of a fire. Once the source of the fire is removed, these materials are extinguished in a few seconds so that the effect of the fire is minimised.
5 Combustive Energy 1600A – approx 60 kWh/sq.m 1600A – approx 5 kWh/sq.m.

Combustive energy is typically 80% -90% less than cables.

6 Future expansion If load on any floor exceeds initial plan, owner has to run an additional cable from a spare feeder on main board to that floor. . By providing extra tap off slots on each floor at the design stage, owner only has to procure a tap off box and plug it in wherever additional load is required. As the plug in can be done live, there is no shut down required for any of the existing clients / circuits. Future Flexibility.
7 Fault withstand levels Limited by conductor size of each circuit. Much higher – typically a 1600 A riser has a fault withstand capability of 60 to 70 kA. Safer in an electrical fault.
8 Installation time Much longer Each riser on a 20-floor building can be installed in approximately 2 to 3 days
9 Voltage drop High impedance if you choose cable size based on each floor current rating Much lower impedance. Hence substantially lower voltage drop.
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capblanc
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#5
In reply to #4

Re: Cables vs. Bus Ducts

12/18/2009 4:58 PM

Brilliant comparison, the case couldn't be made clearer.

Cheers

Chas

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andreY
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Join Date: Nov 2009
Posts: 14
#6
In reply to #4

Re: Cables vs. Bus Ducts

12/19/2009 12:52 PM

thank you VM, nice table.

for buildings it is definitely better decision, but I'm working with plants ( sorry didn't write more detailed question) and overthere I can use busbar into main distribution board (MDB) and Motor Control Centres (MCC) only. Some produsers push me to use busbars from trafos LV side to MDB but by now I'm still for cables. Ather story with HV - at that side buses are preferable.
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Anonymous Poster
#7
In reply to #6

Re: Cables vs. Bus Ducts

12/20/2009 1:16 PM

It is advisable to use Bus Duct From LV of Trf. to MDB since the No. of Cables is very high. Termination would be a problem and it would be difficult to locate fault. Cables are prone to failure than a well designed bus duct.
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giri
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#8
In reply to #4

Re: Cables vs. Bus Ducts

12/27/2009 2:03 AM

Brilliant explanation dear electricalexpert!........Again here I have doubt for you....since the cables has high impedance the fault current should be less in them compared to the bus bars even though the voltage drop is more right???Thank you.....

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electricalexpert65
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#9
In reply to #8

Re: Cables vs. Bus Ducts

12/27/2009 4:41 AM
Re: Cables vs. Bus Ducts
Agreed! But, here we are discussing industrial feeders where the lengths are not much. As such, fault current limitation by cables will not be much. And, with small lengths of cables and with not much limiting in fault current, we may have to shoose switchgear with almost same breaking capacities at the sending end as well as at the receiving end of the cable feeder. As such cables do not have any advantage in such a scenario. Moreover, comparatively the fire rsik assciated with cables is much more than with bus bars.

So, given a chance, I would definitely opt for Bus bars rather than cables at lesat for smaller length feeders.
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Anonymous Poster
#10
In reply to #4

Re: Cables vs. Bus Ducts

02/02/2010 7:02 AM

sir may i have your mail id so that i can ask u some more questions ...
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Anonymous Poster
#12
In reply to #4

Re: Cables vs. Bus Ducts

10/29/2010 7:37 AM

Very excellent job done.
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Anonymous Poster
#11

Re: Cables vs. Bus Ducts

06/21/2010 1:19 PM

You are forgetting the Cons of busducts: damages over time. I have seen damages time and time again to busduct connections, warps, etc. which costs a lot of time and money to replace. Also, you are limited to (2) take-offs per floor, which can be inconvenient, when retrofitting an existing building. Each building should be a case-by-case basis to determine whether busduct or cable/conduit is the better solution. Sometimes you are limited by the wattage per square foot, for a floor, in which case you wouldn't be using busduct to it's full advantage, so it wouldn't make sense. Overall, my view is that niether is better or more convenient, although cable/conduit lasts longer without damage. Each project is particular and should be analyzed separately to determine the best mode of distribution based on power usage per floor, metering or power requirements, length of runs, voltage drop, etc.
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dhayanandhan
Guru
Engineering Fields - Mechanical Engineering - New Member

Join Date: May 2008
Location: CHENNAI, TAMIL NADU, INDIA.
Posts: 1851
Good Answers: 65
#13

Re: Cables vs. Bus Ducts

08/27/2015 12:31 PM

Dear Mr.agnimohanty,

Pl. open the following and you can learn a lot.about BUS DUCT Vs.CABLING

1. https://www.google.co.in/?gfe_rd=cr&ei=ui_fVcG3De7I8AfypaVY&gws_rd=ssl#q=cable+vs+bus+duct

2. http://www.allinterview.com/showanswers/88748/why-are-using-bus-ducts-why-not-using-cables.html

3. bus bar system http://www.electricalengineering-book.com/pdf/chapter-142791.pdf

4. http://www.handh.net/Blog/HH/How-does-a-busway-system-save-me-money-over-wire-and-conduit-

5. https://in.answers.yahoo.com/question/index?qid=20090715233643AAcXYg7

6. http://m.kbc.com.co/Q/branch-cable-vs-bus-duct-pros-and-cons

7. https://books.google.co.in/books?id=tFcUBQAAQBAJ&pg=PA267&lpg=PA267&dq=cable+vs+bus+duct&source=bl&ots=umvsfjLebO&sig=BodsybCOS6XTN03ZBRqVtECSp6M&hl=en&sa=X&ved=0CEkQ6AEwCDgeahUKEwiS4vnv0MnHAhXPcI4KHfdqBOw#v=onepage&q=cable%20vs%20bus%20duct&f=false

DHAYANANDHAN.S
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Users who posted comments:

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