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bimal237
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Join Date: Jul 2012
Posts: 2

How to Decide Earthing Cable Size

04/05/2014 2:07 AM

Presently, i am working in design field. i want to know how to decide earthing cable size for HT & LT motors and instruments. I also confisued between earthing,neutral&grounding.

kindly guide.
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abasins
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Engineering Fields - Power Engineering - New Member

Join Date: Feb 2011
Location: Pakistan
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#1

Re: How to decide earthing cable size

04/05/2014 2:48 AM

1). In the transformer, the HV side (delta connected) has no earthing...

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abasins
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#2
In reply to #1

Re: How to decide earthing cable size

04/05/2014 3:12 AM

In the transformer, the HV side (delta connected) has no neutral... Sorry for that...I don't know what I have been thinking....:)

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Tornado
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#3

Re: How to decide earthing cable size

04/05/2014 4:37 AM

Obtain a copy of your local electrical code, and follow its directions.

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navdeep_goyal
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Join Date: Apr 2014
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#4

Re: How to decide earthing cable size

04/05/2014 10:56 AM

There are very simple ways to find out the same 1st of all you are needed to find out fault level of particular equipment whose earthing to be done.

Then accordingly you may find out the earthing conductor size

for details visit:-http://electrialstandards.blogspot.com/2014/01/calculation-for-min-cross-section-for.html
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wareagle
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#5

Re: How to decide earthing cable size

04/05/2014 12:26 PM

http://cr4.globalspec.com/thread/82873#newcomments
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lyn
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#6

Re: How to decide earthing cable size

04/05/2014 3:28 PM

Please tell us that you ARE NOT "designing" electrical components or installations.

A minuscule amount of knowledge of electronics is required in order to NOT KILL PEOPLE with your designs.

Not understanding the difference between these simple terms speaks volumes of your (lack of) knowledge.

Cable size is determined by the amount of current the cable will be required to carry.

Where is this project located, so that we may look out for the fire?
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brich
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#7

Re: How to Decide Earthing Cable Size

04/05/2014 10:27 PM

I MUST add to Lyn's comments

Give up now and do something else. If you DON'T know the difference between ground and netural you either skipped classes or you are in the WRONG class. Electrical design is not something you can pick up in this forum, and anyone who give you pointers is NOT doing you any favours. Go back to the right class, learn from the teacher, read the books, learn basic 101 electrical theory and THEN go for the design class.

Based on your question you are way out of your depth, I have 1st year trainees that can answer your questions.

One pointer... local codes will not give the answer.. only by knowing the rating of the machine, the csa of the power conductor and the fault current, can you calculate the csa of the earth core.

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pnaban
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#8

Re: How to Decide Earthing Cable Size

04/05/2014 10:52 PM

For power distribution earth cable size depends on size of PD(fuse/CB).

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jmueller
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#9

Re: How to Decide Earthing Cable Size

04/06/2014 8:01 PM

Sir,

Your post tells me that English is not your first language. Keep on working on it and you will get to know the differences between words.

In many parts of the world, the word "earthing" refers to the same function as "grounding" does in other parts of the world. However there are some smaller but critical shades of meaning that depend on the purpose of the connection. The conductor that performs this (or these) purposes is not supposed to be a current-carrying conductor under normal conditions.

The word "neutral" generally refers to a conductor that does carry current and is electrically located in the midpoint between other current-carrying conductors in a multi-conductor circuit. In branches from such a circuit or system, it also refers to any conductor that is connected to the neutral at the branch's origin. An example of a neutral is the midpoint of a 3-phase wye. Depending on the voltage of the circuit and the purpose of the circuit, the neutral is very often connected to ground/earth near or at its origin. BUT you must not assume that it is (or must be) grounded/earthed.

Electricity is far from being an exact science or discipline. We are always finding new things, developing new products, and learning from faults/failures/accidents. Over time, this learning has been condensed into a large number of rules that form a minimum standard for electrical work, such as the electrical code for your jurisdiction. It does not tell you how to do the work or how to design it. That is why the many replies you have already received are so blunt in saying to go to classes (read books, etc.). Your question is very open-ended. Depending on the exact conditions for which you are designing, the recommended method of earthing/grounding can be quite different. This forum has members who can give you specific answers to specific questions, when they feel it is safe or wise to do so.

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PWSlack
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#10

Re: How to Decide Earthing Cable Size

04/07/2014 6:04 AM

As previously stated, the difference between grounding and earthing is the Atlantic Ocean. The confusion arises from having two nations divided by a common language.

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Anonymous Poster #1
#11

Re: How to Decide Earthing Cable Size

04/07/2014 6:07 AM

presently, you are in design field

So what fields have you been before this.
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Users who posted comments:

abasins (2); Anonymous Poster (1); brich (1); jmueller (1); lyn (1); navdeep_goyal (1); pnaban (1); PWSlack (1); Tornado (1); wareagle (1)

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