r1, R1,r2, R2... help!

[diGreez]

Hi Guys,

Probably looking dum, but now it confused me.
I am just a still starting student and lost my plot on this...
r1, R1,r2, R2 thought it is circuit numeration, then that it is circuit resistance......

can someone please explain it to me what it is and what's the difference between capital R and not.
I googled it for 3 days, searched in regs, OSG, EGBRegs,EIDG...

Nearest I got is Reg's book page 39: R1 - Resistance of line conductor of a distribution or final circuit, R2 - resistance of circuit protective conductor(CPC) of a distribution or final circuit.
is that it? so there is no difference between capital R and r?

Please help as it just sucks the life of me...
Thanks in advance.

 

[tony mc]

Have a look at the OSG page 10 re testing ring final circuits.

The little r1 is the end to end continuity reading of your line conductor.

r2 CPC end to end

rn Neutral end to end.

Hope that helps.

Tony

 

[mickys86]

Have a look in the testing section on the onsite guide.

 

[diGreez]

Thanks a lot Guys! It's so simple... but it was just killing me... Thanks.

 

[Silly Sausage]

Burn this into your brain...

r1, r2 & rn are the resistances of the cables in an RFC

R1+R2 is the Line/Earth resistance of a circuit.

Note the use of upper and lower case letters!

 

[sparks1973]

right...
your end to end resistances (on a ring)...would be r1...r2... and rn
when you cross over......and so your goin round the points (breakout box)......then ti would be R1 R2.....R2 Rn....
do you see the difference?

small r for your end to ends

big R for you resistances round the ring..

and method 2 (wander lead) ...which is also your end to end resistances will also be a big R...but not an R1 R2 of course......as you have only measured the resistance of R2......so thats what it is...
happy testing.
Glenn.

 

[sparks1973]

and what value can you expect to get on an R1 R2...?and what may alter this...?

answer please..

 

[diGreez]

and what value can you expect to get on an R1 R2...?and what may alter this...?

answer please..

ohm - lengths of the cables, Ze, some faults possible...? :|

 

[mickys86]

ohm - lengths of the cables, Ze, some faults possible...? :|

Have a read of the testing section and then answer his question haha
(Hint** stick to reading about RFC)

 

[diGreez]

so according to you guys and to OSG:
R1 - Line Conductor
R2 - Protective conductor (why not just they call it CPC as usually?)
?? - neutral Conductor?
R1+R2 testing for faults, by checking ?resistance?

r1 - Line end to end
rn - neutral end to end
r2 - Protective conductor CPC end to end
end to end is for checking for mis-connection, continuity of that conductors circuit?

Is it right?

 

[Strima]

I was under the impression that R was measured and r was calculated... But I haven't played with a ring for a while... :lol:

 

[sparks1973]

you wish to carry out a resistance test on a ring final....
all conductors are of approx the same length..
if you get a value of resistance of 1.32 ohms on r1...

state;
1) THE INSTRUMENT USED................................................................1 point

2)THE EXPECTED VALUE OF r2...........................................................1 point

3EXPECTED VALUE OF R1+R2 AROUND THE RING..(bareing spurs in mind)............1 point

 

[telectrix]

in Q2, i assume you mean using T/E, else r2 would = r1 if cpc were the same size as the line conductor. sounds like an ambiguouse c&g effort. LOL.

 

[sparks1973]

in Q2, i assume you mean using T/E, else r2 would = r1 if cpc were the same size as the line conductor. sounds like an ambiguouse c&g effort. LOL.

sorry tel...yes i was just coming to correctin it as 2.5/1.5 flat T&E 70* thermoplatic...
lol...
thanks Tel..

 

[sparks1973]

A 1 tel..