0.00 ohms r1+r2 on radial circuit?

[Newbie90]

Hi all,

I've tested several radial circuits and only getting 0.00 ohms on the r+r2 test (zero'd leads)

2 of the radials only supplies one socket each and are approx. 3 metres in total length. (zs 0.25 and 0.21)
Another radial only supplies one socket and is appox. 5m in length. (zs 0.35)
The final radial supplies 2 sockets and approx. 7m in total length. (zs 0.53)

Are the readings due to the length of the run or could it be the batteries need changing on my Fluke Multifunction (even though no battery warning)

Thanks

 

[Plonker 3]

Have you removed the link and carried the same to test?

 

[telectrix]

3m of 2.5/1.5 will have a R1+R2 of 0.06. probably too low for your meter's resolution. try witout nulling the leads, then subtract the lead resistance from the measurement.

 

[Pete999]

Do you have a low ohms scale on your MFT?

 

[Newbie90]

Thanks for the quick replies.

The Fluke Multifunction is auto ranging for the continuity tests and according to their website, on the 20 ohms scale for continuity testing it's resolution is 0.01 ohms.

So I would of thought it could read as little as 0.01 ohms.

I've heard they produce funny readings when they need new batteries but I've had no warning.

 

[Pete999]

Just to prove your MFT how about fitting some replacement batteries, and see if that make any difference

 

[telectrix]

and you've been a member long enough that you should know there's no such thing as r1+r2 on a radial . :6:

 

[Silly Sausage]

Or try your instrument on some lengths of spare cable and see what you get.
Compare your readings against the theoretical values in the back of the OSG.


Ha, missed that one Tel!

 

[Newbie90]

and you've been a member long enough that you should know there's no such thing as r1+r2 on a radial . :6:

What do you mean?

You do an r1+r2 test on every circuit.

 

[telectrix]

rubbish. r1,rN, and r2 are end/end resistances of a RFC.

 

[Hobsoni]

telectrix is being sarcastic

 

[Newbie90]

rubbish. r1,rN, and r2 are end/end resistances of a RFC.

Agreed, but when testing the continuity of cpc's by linking out line and earth and testing at each point, the measurement obtained is r1+r2.

 

[brucelee]

R1+R2 is what your looking for

 

[Plonker 3]

That's R1+R2

 

[Pete999]

and you've been a member long enough that you should know there's no such thing as r1+r2 on a radial . :6:

Missed that one mate teach me to note the diff in r1+r2 and R1+R2 wont it?

 

[Hobsoni]

Although technically its R1+R2 for your radial circuits. Whereas you record r1+r2 around your RFC with the highest value being classed as R1+R2. Is this a play on the capital 'R' telectrix?

 

[Plonker 3]

R1+R2 and r1+r2 on a RFC are two different values.

 

[Silly Sausage]

Although technically its R1+R2 for your radial circuits. Whereas you record r1+r2 around your RFC with the highest value being classed as R1+R2. Is this a play on the capital 'R' telectrix?

Don't forget your divide by 4 now!

 

[Hobsoni]

Thanks gents. Bring on the onslaught

 

[Silly Sausage]

I'm off to dig out my GN3 so I don't make a balls up!