R1+R2 of zero zilch nothing?......

[Deleted member 26818]

Make sure, you join the line and CPC together at the other end from where you are testing.

 

[Octopus]

I would suggest you also try R1 + Rn

 

[Pete999]

Fair comment fella, some testers have different scales, and if your on the wrong one a zero showing isn't unusual hence mine and Petes question.

 

[Fitzy]

Have you got any old or new lengths of cable you can test your MFT with?

Do you also have a ‘Calibration Card or a calibration box’?

We used the Kewtech KT63 MFT in training and they’re
auto-ranging.

 

[Andrew Marshall]

Need a ohmmeter / multimeter with a resolution of 3 digits, ie 3 decimal places. Most multifunction testers are only 2 places

 

[Baddegg]

Thanks Archy

 

[Baddegg]

Thanks to all who replied as always loads of good advice,

 

[westward10]

What you could do it add a known higher resistance in the circuit as your circuit resistance is so low. Take a length of 1.0 singles which will add significant resistance and measure this resistance, then incorporate this into the circuit and remeasure. If you deduct the resistance of the first reading from the second you may get a result for the cable.

 

[Baddegg]

Resistance of copper per metre(mohms/M) appendix I of OSG:

10mm=1.83
4mm=4.61

1.83+4.61=6.44

6.44*8=51.52

51.52/1000=0.05 ohms.

Thanks strima, that calculation with Archie’s advice would account for the zero reading,
I am going to run some test tests tomorrow to put my mind at ease that the testers are working correctly, I’ll cut cable to exact lengths and then compare to osg/byb

 

[Octopus]

Thanks to all who replied as always loads of good advice,

Good man ............... no arsey responses , and feedback too

Seriously, this is how the forum should be - competent sparks, helping sparks

And if you do cut lengths, don't do them too short ...........

 

[Pete999]

Thanks strima, that calculation with Archie’s advice would account for the zero reading,
I am going to run some test tests tomorrow to put my mind at ease that the testers are working correctly, I’ll cut cable to exact lengths and then compare to osg/byb

Save cable buy a check box /card

 

[Toneyz]

What scale have you set on your MFT?

What scale is this Pete? my MFT only has the low ohms continuity you select as the same as the Kewtech KT63, not sure about the individual continuity/insulation resistance testers.

 

[Baddegg]

Good man ............... no arsey responses , and feedback too

Seriously, this is how the forum should be - competent sparks, helping sparks

And if you do cut lengths, don't do them too short ...........

I always appreciate the advice I’m given on here,You couldn’t buy the wealth of knowledge available, but.....I’m far from a spark!......yet
Thanks again

 

[Strima]

Thanks strima, that calculation with Archie’s advice would account for the zero reading,
I am going to run some test tests tomorrow to put my mind at ease that the testers are working correctly, I’ll cut cable to exact lengths and then compare to osg/byb

Don’t bother with exact lengths as resistance will change due to temperature variances.

Use the OSG to give you a ball park figure to work from.

 

[Baddegg]

Save cable buy a check box /card

I will be looking into that shortly Pete thanks

 

[Strima]

Show off

It’s not often I get to show off...

 

[Pete999]

What scale is this Pete? my MFT only has the low ohms continuity you select as the same as the Kewtech KT63, not sure about the individual continuity/insulation resistance testers.

I was thinking the OP may have had his MFT on the wrong setting, ie IR or something else continuity is OK

 

[Toneyz]

This can't be a new problem most testers are two digits. What do others put down when they do an R1+R2 to a double socket 2Mtrs down from the consumer unit? I usually get 0.00 ohms and record 0.01 ohms.

 

[westward10]

If it is 2m away it cannot possibly be 0.01 ohm.

 

[Toneyz]

If it is 2m away it cannot possibly be 0.01 ohm.

The point that I was trying to make is that you get a circuit very close to the distribution equipment value is too small.