Continuity Testing reliability

[rustynails]

Friday I was getting continuity readings from my tester which start with a reasonable figure then drop off the scale to 0.00. This tended to occur more on the existing circuits rather than on new circuits. can someone shed any light on this?

 

[Pete999]

Friday I was getting continuity readings from my tester which start with a reasonable figure then drop off the scale to 0.00. This tended to occur more on the existing circuits rather than on new circuits. can someone shed any light on this?

Iffy test meter, Iffy connections

 

[Leesparkykent]

Low battery?

 

[rustynails]

Iffy test meter, Iffy connections

eventually I did get readings which were stable and ok to record. however I'm unsure about the tester at the moment so am looking to check that the tester is working correctly by using a calcard that I purchased 5 months ago and never got working...

 

[rustynails]

Low battery?

I also changed batteries on Friday.. which helped at the time.

today I'd like to check the tester out with calcard but could never get to grips with it because at the first stage I fell over. on the back of the cal card you are supposed to record bench mark readings given to you from the certificate of calibration. With the continuity no of the ranges on the back of the card were tested. The card wantd

0.25 ohm
0.5 ohm
1 ohm
2 ohm
5 ohm

off the cert I had under a heading of continuity resistance

20 ohm range
20 ohm range
200 ohm range
2000 ohm range

with IR the card wanted

0.5M
1M
2M
10M
20M

cert had

1 Mohm
10 Mohm
190 Mohm

with tolerance, applied value and reading I guessed I had to record the reading on the calcard so the only value that matched the card was the insulation resistance of 1 Mohm @ 500v which reading was 1.01 mohm.

 

[Midwest]

I also changed batteries on Friday.. which helped at the time.

today I'd like to check the tester out with calcard but could never get to grips with it because at the first stage I fell over. on the back of the cal card you are supposed to record bench mark readings given to you from the certificate of calibration. With the continuity no of the ranges on the back of the card were tested. The card wantd

Not quite with you? Using your calcard for the first time, its assumed your MFT is newly professionally calibrated.

Then with your MFT test the insulation and continuity readings you obtain from the card, that your MFT displays (these are recorded on the back of the calcard). From there on in, your should obtain the same readings. If they are 10% out, time to get your MFT re-calibrated or three years, which is either sooner.

The certificate, isn't that to record your monthly checks?

Re fluctuations in your readings, if your MFT dos this against a know resistance i.e. your calcard, time for a visit to the repair shop.

https://www.niceicdirect.com/WebRoo...CA90/69D4/8EC2/0A0A/124C/80C3/Information.pdf

Or have I read you wrong?

 

[Octopus]

Metrel tester which needs new leads?

 

[rustynails]

Not quite with you? Using your calcard for the first time, its assumed your MFT is newly professionally calibrated.

Then with your MFT test the insulation and continuity readings you obtain from the card, that your MFT displays (these are recorded on the back of the calcard). From there on in, your should obtain the same readings. If they are 10% out, time to get your MFT re-calibrated or three years, which is either sooner.

The certificate, isn't that to record your monthly checks?

Re fluctuations in your readings, if your MFT dos this against a know resistance i.e. your calcard, time for a visit to the repair shop.

https://www.niceicdirect.com/WebRoo...CA90/69D4/8EC2/0A0A/124C/80C3/Information.pdf

Or have I read you wrong?

I understand a bit better now having re read the instructions for cal card seems the testers continuity is out somewhat, it is nearing its annual calibration date anyway.

 

[DPG]

I understand a bit better now having re read the instructions for cal card seems the testers continuity is out somewhat, it is nearing its annual calibration date anyway.

This shows the value of keeping checks on your tester. The problem is now that not only is your tester not fit for using at the minute, but also the tests you have made recently may be wrong. Daz

 

[Midwest]

I understand a bit better now having re read the instructions for cal card seems the testers continuity is out somewhat, it is nearing its annual calibration date anyway.

I had fluctuations with readings with my Megger 1730, which I eventually realised it was a problem with one of its terminals requiring repair. Fortunately it was still under warranty.