Earth Fault Loop Impedance Path

[wams]

Hi All,

During the 2391 theory exam next week, im more than likely going to be asked to draw the earth fault paths for TN-S, TN-C-S and TT systems. Iv'e been looking at many diagrams on the web and in books, but I find the paths drawn in Alan Lynch's The Part P Doctor (2nd Fix) alot more easier to understand. So I have decided to use his diagrams to answer the question, if it appears in the exam. Now; if I were to copy the paths by memory would the examiner know that and deduct marks? Or does it not matter what diagrams I use as long as i can prove I have an understanding of such systems?

Thanks

Wams

 

[Sharpend]

The earth fault path is exactly that the quickest route to earth, if you want to do a fancy drawing be my guest but it won't score you any more points.

 

[wams]

You also have to have the correct terminology (specific words) on the drawing to gain full marks

I have, I've been adding the Correct terminology when I practise drawing the diagrams.

Thanks

Wams

 

[Bacon]

It's allways the last question on paper and worth an easy 15 marks.

 

[Hefferl]

I too thought this question was a certainty but it did not appear on my paper. X(

I would say that you're fine to use any reasonable representation of these paths that you prefer - just as long as what you draw is accurate, represents the correct earthing system as stated in the question (draw the wrong system and although you might have identified correct common components you will get zero marks) and that you label all the important components using all the correct terminology

Hi All,During the 2391 theory exam next week, im more than likely going to be asked to draw the earth fault paths for TN-S, TN-C-S and TT systems. Iv'e been looking at many diagrams on the web and in books, but I find the paths drawn in Alan Lynch's The Part P Doctor (2nd Fix) alot more easier to understand. So I have decided to use his diagrams to answer the question, if it appears in the exam. Now; if I were to copy the paths by memory would the examiner know that and deduct marks? Or does it not matter what diagrams I use as long as i can prove I have an understanding of such systems?

Thanks

Wams

 

[Technician]

As a tip, when you do your sketch, show with dotted

lines that there are two other phases each with their

own fault loops on them, 120 degrees apart.

Another one is to show, by whatever means you can,

that there are two parts to it.

Indicate also exactly where R1 and R2 are located.

(If Alan Lynch's sketches do not already show these

features)

 

[a1]

And make sure it is well labelled too.

 

[wams]

Thanks everyone,

Points noted!!

 

[Technician]

Point taken, Canoeboy; It was one of the many

points that my tutor made to me when I did my

exam when I was working towards it. This, and

the importance of full completion of procedures

on all testing methods.