PAT Testing fail query

[Rozzerdinho]

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Hi,

I perform annual PAT checks for my company (office and workshop). The Apollo 400 machine we use has recently gone for calibration and service and since it's come back, items which passed easily last year (Earth Continuity below 0.1ohm), are now not passing. I've now raised the earth continuity limit to factor in cable resistance etc. but why is it that some items which were say 0.8ohm are now 0.17ohm and wont pass? Any ideas?

Many thanks,

 

[littlespark]

Because it wasn’t calibrated.

Out of calibration means that something is off inside the machine which can give false readings.
When it goes to be calibrated, these “off” things are adjusted against test examples with known good values…. Which brings the results back to being more accurate.

 

[Rozzerdinho]

Because it wasn’t calibrated.

Out of calibration means that something is off inside the machine which can give false readings.
When it goes to be calibrated, these “off” things are adjusted against test examples with known good values…. Which brings the results back to being more accurate.

Hi. We have annual calibration certs since we purchased the machine.

 

[DPG]

0.17 Ohms is less than 0.8 Ohms, so that's a better earth continuity result. Uess I've misunderstood your post.

 

[Rozzerdinho]

0.17 Ohms is less than 0.8 Ohms, so that's a better earth continuity result. Uess I've misunderstood your post.

Apologies it should say 0.08 and not 0.8.

 

[DPG]

Ah fair enough. Have you got a decent multimeter you could use to verify the results. Vital to get good connections obviously when you're measuring such low resistances.

 

[Avo Mk8]

If you keep your PAT results from previous years, can you review these for evidence there has been a step change in the Apollo results after calibration, if that is what's happened.
e.g. If you have results for workshop equipment that showed a value of around 0.08 ohms year on year for 3 or 4 years, and now the value is 0.17 ohms, and you then look at the results for more equipment, and they have all done the same thing (even better if they are now all around 0.09 ohms higher), then you have solid evidence your Apollo is suddenly producing consistently different results from all previous years, and I would send it back for investigation.

It's not that unusual for equipment to get upset in transit, or less likely for an error to be made during calibration.
If the data gives evidence there's a consistent change in the Apollo's results, the calibration company ought to look into it for you.

 

[Rozzerdinho]

If you keep your PAT results from previous years, can you review these for evidence there has been a step change in the Apollo results after calibration, if that is what's happened.
e.g. If you have results for workshop equipment that showed a value of around 0.08 ohms year on year for 3 or 4 years, and now the value is 0.17 ohms, and you then look at the results for more equipment, and they have all done the same thing (even better if they are now all around 0.09 ohms higher), then you have solid evidence your Apollo is suddenly producing consistently different results from all previous years, and I would send it back for investigation.

It's not that unusual for equipment to get upset in transit, or less likely for an error to be made during calibration.
If the data gives evidence there's a consistent change in the Apollo's results, the calibration company ought to look into it for you.

Hi Avo,

Thanks for the reply. Think that's what i'll end up doing. The cal cert says everything is fine but i'll get a better picture once start comparing back.