Discuss R1 + R2 does not equal (R1+R2) in example in On Site Guide. in the Electrical Wiring, Theories and Regulations area at ElectriciansForums.net

HappyHippyDad

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I have always been a bit confused about boxes 10,12 and 13 in the example of a completed 'Form 4 - schedule of test results'.

I understand why the value we get for R1+R2 (when measured at a socket) is a quarter of the end to end resistances, but why on the form is this not more clear?

Box 10 (R1) and Box 11 (R2) do not equal Box 13 (R1 + R2). Again I understand why, but it just seems wrong to have a box for R1 and a box for R2 but adding them together is not R1+R2.

Its annoying :cuss:
 
That's because its not R1... Its r1!! And when you measure a radial, you are measuring R1 + R2. So in affect your not adding r1 to r2, although we do this for a ring to see if our readings are correct.
 
surely your forms have a column for r1+r2 for RFCs?
 
You're right even in GN3 'Form 4 - schedule of test results' note13 refers to Ring (R1+R2) and not r1+r2 bloody IET lol
 
No. They are Castline Formfill (free).

Do you think it's a mistake?
Doesn't really matter, does it?

You either have to multiply mine by 4 to get 'r' or divide yours by 4 to get 'R'.
 
I agree............................................................
I have always been a bit confused about boxes 10,12 and 13 in the example of a completed 'Form 4 - schedule of test results'.

I understand why the value we get for R1+R2 (when measured at a socket) is a quarter of the end to end resistances, but why on the form is this not more clear?

Box 10 (R1) and Box 11 (R2) do not equal Box 13 (R1 + R2). Again I understand why, but it just seems wrong to have a box for R1 and a box for R2 but adding them together is not R1+R2.

Its annoying :cuss:
 
He said col 13 ????
Yes but col. 13 IS R1+R2.

He was wondering why cols. 10 (r1) and 12 (r2) do not add up to col 13 because he mistakenly called them R1 and R2.

As I wrote, mine do as they ARE R1 and R2 not r1 and r2.

Col. 11 (rn or Rn) is incidental but the same.

Is that clear?
 
r is for ring
R is for resistance
R1 + R2 is the resistance of the earth and line of the circuit connected together

but if you do add r1 and r2 together and divide by 4 you should get R1 + R2 in theory

Due to parellel Earths though you may not get a text book reading

As stated R and r are completely diferent
 
clear to me, but you couldn't of read GB£ page 100 note 13 Is that clear?
Yes but col. 13 IS R1+R2.

He was wondering why cols. 10 (r1) and 12 (r2) do not add up to col 13 because he mistakenly called them R1 and R2.

As I wrote, mine do as they ARE R1 and R2 not r1 and r2.

Col. 11 (rn or Rn) is incidental but the same.

Is that clear?
 
I have found it in the BGB.

You mean measuring from a spur would make R1+R2 more than (r1+r2)/4.

That would be true but I still think you have missed the point of the OP and my comments.
 

Reply to R1 + R2 does not equal (R1+R2) in example in On Site Guide. in the Electrical Wiring, Theories and Regulations area at ElectriciansForums.net

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