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islam_nemr
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Join Date: Feb 2011
Posts: 2

Power Distribution Board

02/21/2011 11:29 AM

Hi everyone,

I'm an electrical engineering student, I have 1 small question to ask:

in the 3 phase power distribution board which we see inside the buildings. there are 5 wires used. what are these wires used for??

as i know three of them are coming from the 3 phase system. what about the remaining 2 wires??

regards,
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redfred
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Engineering Fields - Electrical Engineering - Been there, done that. Engineering Fields - Control Engineering - New Member

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#1

Re: power distribution board.

02/21/2011 11:36 AM

Neutral and ground immediately come to my mind. But depending on the installation this could also be communication and instrumentation cabling. I'm certain you will find in your studies what these terms mean and can then immediately know what those two cables could be by just a visual inspection.

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rakesh_semwal
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India - Member - New Member Engineering Fields - Electromechanical Engineering - New Member

Join Date: Oct 2006
Location: India, 200 Km. North of Delhi.
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#2

Re: power distribution board.

02/21/2011 11:36 AM

For how long are you an electrical Engineering students, didn't you ever heard of neutral and earth?

Knowing these two is pre condition for having a title of

"Electrical engineering student"
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PWSlack
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#3
In reply to #2

Re: power distribution board.

02/21/2011 12:02 PM

<...Knowing these two is pre condition for having a title of "Electrical engineering student"...>

Not necessarily. It might be 'day one' of the course.

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rakesh_semwal
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#4
In reply to #3

Re: power distribution board.

02/21/2011 12:10 PM

AtLeast in my country grade 12th with physics is necessary to qualify for entering in electrical engineering education, and I know this is covered in 12th grade physics here.

MY apology if OP is from some where else where standards are different.
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PWSlack
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#8
In reply to #4

Re: power distribution board.

02/21/2011 5:48 PM

As the OP hasn't revealed a location, the forum is none the wiser.

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islam_nemr
Participant

Join Date: Feb 2011
Posts: 2
#5
In reply to #2

Re: power distribution board.

02/21/2011 12:50 PM

for 3 years, is that OK with you Mr. GENIUS !!! for us not only grade 12 students know that, but younger ones already hear about neutral and earth.

please answer the question (if you know) otherwise keep your JOKES aside.
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redfred
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#6
In reply to #5

Re: power distribution board.

02/21/2011 1:04 PM

Rakesh's comment was not called for and neither are yours.

Do you honestly think that we can read your mind to point out the detail that you missed. Well you're in luck I can.

Now lean a little closer to your computer screen so I can get a better look...

.

.

.

Just a little closer, and can you lower your shoulder.

.

.

.

.

.

.

.

Don't look at the screen yet, I almost got it.

.

.

.

.

.

.

.

.

.

There we are.

Now I see it. It's just as I thought.

Let me take a picture now so you can look, too.

Hold still a minute.

.

<click>

.

.

.

Just as I suspected there's nothing in there. You've wasted your money and time trying to work in Engineering. You cannot communicate any of the relevant points of a situation to another person who was not in the classroom with you.

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TonyS
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#7
In reply to #6

Re: power distribution board.

02/21/2011 1:11 PM

I like that. GA

Our OP gets me downright worried!

Br*in De*d

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mountk2
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Join Date: Jun 2010
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Good Answers: 10
#9

Re: Power Distribution Board

02/21/2011 10:43 PM

Check on the single line drawings with the symbol list, wiring details and other information is there.

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67model
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Join Date: Dec 2010
Posts: 1686
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#10

Re: Power Distribution Board

02/23/2011 5:39 AM

Since you recognize that the remaining two wires are called neutral and earth, did you mean "What are the neutral and earth wires used for?". It would have been better if you had asked that to begin with.

The short answer is that 1) the neutral allows the distribution of single phase supply e.g. 220V with a 380V line to line three phase supply which is suitable for lighting and sockets for plug-in equipment 2) The earth provides bonding back to the source of the supply so that any connection between live and earthed metalwork on the site will cause disconnection for safety by automatic devices. 3) The earth is connected to the mass of the ground of the world at one or more points by buried metalwork in an attempt to reduce dangerous potential gradients, should live come into accidental contact with ground somewhere.

An ideal solution to 3) is difficult because ground has a high and variable resistance. There are several systems in use, some combining live and neutral outside buildings.

Only last week, two valuable racehorses were killed because of accidental damage to an underground power cable.
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Users who posted comments:

67model (1); islam_nemr (1); mountk2 (1); PWSlack (2); rakesh_semwal (2); redfred (2); TonyS (1)

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