R1 plus R2 test

[m4tty]

Hi,

Just wondered how most people do the r1+r2 test. Do you take the Live out the MCB and put in Earth Bar? or do you use a shorting out lead?

Do these shorting out leads save a lot of time. Are they home made or bought from somewhere?

Thanks

Matt

 

[Brian 157]

I use a connector block. Unless you are dealling with an all insulated installation leaving the CPC in the earth bar can give a false reading as the R2 value will be lowered by parallel paths (a steel conduit/trunking installation is an obvious example) and you may obtain a reading even with a broken CPC. Whilst you will struggle to eliminate all parallel paths in such an installation you have to make an effort.

If using a link-lead (bought or homemade) check the resistance of the lead & if it's significant remember to deduct it from your reading.

 

[paul b b]

i stick a short bit of 2.5 from the earth bar to mcb, if you turn the rcd on (power off ofcause) you can test 1 half of the board with out having to short every mcb!

 

[ADS]

i stick a short bit of 2.5 from the earth bar to mcb, if you turn the rcd on (power off ofcause) you can test 1 half of the board with out having to short every mcb!

Explanation please? :| ???

 

[PIP IOM]

+1

 

[matt.leung]

test link circuit by circuit.... cable by cable....

 

[Andy™]

i stick a short bit of 2.5 from the earth bar to mcb, if you turn the rcd on (power off ofcause) you can test 1 half of the board with out having to short every mcb!

you can also do it by putting the link into an MCB, and turning all MCB's on (main switch off, obviously. unless you want to test the MCB. not recommended)

 

[ProDave]

Hi,Just wondered how most people do the r1+r2 test. Do you take the Live out the MCB and put in Earth Bar? or do you use a shorting out lead?

Do these shorting out leads save a lot of time. Are they home made or bought from somewhere?

Thanks

Matt

Take the live out of the MCB. Shorting out lead can result in a bad day explode (see the thread the other day when what looked like a radial was in fact the end of a ring fed from a different MCB so was still live when it's MCB was turned off)

 

[kme]

I have a set of clip leads from maplin, about 6" long with mini croc clips on the end. I clip it across my probes for nulling (auto factoring in the resistance of the lead ), then clip it between the ends of the circuit. Go to other end and test. Job done.

KME

 

[sparkytim]

I have one of these

send him to end of Radial to put L-E short on and I stay at CU with Meter

 

[Evans Electric]

Where do you get them from Sparky ?

 

[sparkytim]

Found em under here

 

[ISSWWW]

Well i will not profess to be able to add much in the way of procedure or how to carry out the testing itself but we do seem to have a lot of interest in these if its of any help.

.

 

[paul b b]

Explanation please? :| ???

2.5 from met in cu to the first mcb, turn on all other mcb's (as said main switch off) and you can test the R1+R2 of all mcb's fed by rcd as the first one

 

[m4tty]

2.5 from met in cu to the first mcb, turn on all other mcb's (as said main switch off) and you can test the R1+R2 of all mcb's fed by rcd as the first one

Is that the same as going from earth terminal in cu to buzz bar?

 

[Andy™]

Is that the same as going from earth terminal in cu to buzz bar?

yes

 

[paul b b]

Is that the same as going from earth terminal in cu to buzz bar?

yes

 

[ADS]

2.5 from met in cu to the first mcb, turn on all other mcb's (as said main switch off) and you can test the R1+R2 of all mcb's fed by rcd as the first one

Yeh, that works - that isn't what you said though

i stick a short bit of 2.5 from the earth bar to mcb, if you turn the rcd on (power off ofcause) you can test 1 half of the board with out having to short every mcb!

 

[a1]

I have a set of clip leads from maplin, about 6" long with mini croc clips on the end. I clip it across my probes for nulling (auto factoring in the resistance of the lead ), then clip it between the ends of the circuit. Go to other end and test. Job done. KME

+1

But mine are home made.

 

[Andy™]

+1But mine are home made.

so are mine. got loads in different lengths. useful for many things