r1 and r2

Help Support Talk Electrician Forum:

djedstar

Junior Member
Joined
Sep 23, 2008
Messages
6
Reaction score
0
what are these is it earth and neutral or neautral and live or earth and live or is it live and switch wire in atwo way or intermediate lighting circuit

thanks got an exam in an hour so any help greatly appreciated

 

seajayess

Senior Member
Joined
May 28, 2008
Messages
272
Reaction score
0
The answer to your question is r1 is the end to end resistance reading of the Line conductor and r2 is the end to end resistance reading of the CPC or did you mean R1 + R2 which is the resistance of the Line conductor + the CPC end to end resistance of the Neutral would be rN hope this helps CJS :^O

 

SPECIAL LOCATION

Trailer Boy - Electrician.
Joined
Mar 28, 2008
Messages
13,633
Reaction score
317
Just to add...

the convention used on some electrical certs, EG NICEIC, is that..

r1 is the measured end to end line(phase/live) conductor of a ring.

rn is the measured end to end neutral conductor of a ring.

r2 is the measured end to end CPC conductor of a ring.

{**lower case letters**}

R1+R2 is the loop resistance up the line(phase/live) and back down the CPC.

when the Line & CPC are strapped together at the CU. as used with Zs calculations.

{**upper case letters**}

Where Zs= Ze+(R1+R2).

and with a ring circuit R1+R2 = (r1+r2)/4

that is Lives & Cpc's {i hate calling it "LINE" phtt!} strapped at CU..

meter continuity at furthest point on the ring AND assuming the ring has NO spurs off it.

If there was a spur the R1+R2 value would be ((r1+r2)/4)+the resistance of R1 & R2 of the longest spur!!

HOWEVER..

Part 2 of wiring regs.. page 36, makes NO differentiation between 'R' and 'r'...

whereas it does between 'C' and 'c' ????

Also the model EIC form schedule of test results.. pg 341..

only specifies an R1+R2 to be noted... (no r1,r2 or rn!)...

so there you go..

Think that is most combinations and permutations of RrRrRrRrRrRr whatever!!!

:p ; ) ;) :D

 

Admin1

Forum Founder
Joined
Feb 6, 2008
Messages
10,229
Reaction score
-1
Also proviing Polarity - where the R1 + R2 method is used. :)

 
Top