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Calibration for minimal use new tester

PATGuard 3 Forum

Re: Calibration for minimal use new tester

Postby Alan Freeman » Wed May 09, 2012 6:59 am


Unfortunately, the answer has to be "Yes".

I used to work in a cal lab many moons ago. Even equipment which was not used from one year to the next still has to have an annual "MOT" to be known to be accurate.

Having mentioned MOT, would your car be legal on the road more than 12 months since it's last MOT even with the precise same mileage (ie not driven)?? Same principal.

The justification has got to be that you don't KNOW how accurate it is if it hasn't been checked, and should the worst happen (fire or shock) the HSE/insurance would ask to see a CURRENT PAT certificate issued using a valid cal certificated machine. This is the main reason why it is not really viable for a company to perform their own PAT testing service. Not only does the inspector not have the regular experience, the costs are prohibative.

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Re: Calibration for minimal use new tester

Postby Jim Wallace » Sun May 13, 2012 11:42 pm

Hi Led

I understand where Alan is coming from with the MoT analogy but I take your point about legal requirements etc. In some ways its similar to an MoT in that calibration only verifies the performance/accuracy at the time of calibration. That's why the IET recomend interim checks to confirm on-going accuracy between calibrations. The CoP recomends that instruments are calibrated in accordance with the manufactures instructions and most (including Seaward) recomend annual calibration.

The amount of use does not have a significant impact on the calibration as changes in performance are normally due to component aging or drift rather than wear and tear. Our products do have some moving parts (relay contacts for example) but are designed such that these do not impact on the measurement accuracy.

The other factors is the requirements of organisations such as NICEIC, NAPIT etc who make recomend calibration or in some cases companies require calibration certificates as part of the ISO 9000 system.

If for no reason other than peace of mind, it's worth checking the performance. A lot of companies use checkboxes or other devices to perform on-going checks. This is generally good practise as it avoids finding out during an annual calibration that the accuracy has drifted and then pondering when did it go out of cal and how many historical tests may have been affected.
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Re: Calibration for minimal use new tester

Postby verstapp » Mon May 14, 2012 6:46 am

Thinking from the point of view of solving the problem rather than nitpicking the law,
if I had less than 100 items a year to test I wouldn't buy a tester at all but instead hire someone for a day to do it for me.
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Re: Calibration for minimal use new tester

Postby Jim Wallace » Mon Jun 11, 2012 10:46 pm

Hi Led

All of our products are calibrated twice with independent calibration systems (to detect errors in the cal system) and are shipped with a certificate of conformity. Some customers want an actual calibration certificate and I suspect this is what the retailers (or manufacturers) are offering as an additional service. This generally involves a calibration engineer sitting down and manually taking and recording a set of measurements in a controlled environment and is a service we charge for.

I take your point about vested interest and of course it is a revenue stream for us (and other manufacturers) but it is a service requested by our customers. Manufacturers recomend a calibration interval but at the end of the day, its the users decision.

A service is probably a better analogy, not least because we actually offer a service where in addition to calibrating the equipment we will replace any parts that are subject to wear and tear - typically power relays.
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Re: Calibration for minimal use new tester

Postby thevans » Wed Jul 16, 2014 1:18 pm

Hi Jim Wallace,
I am a newbe on the site so kindly excuse any incorrect protocol.
Our company in Saudi Arabia has purchased three (3) of the Prime Test 100 PAT Testers.
We purchased the above only to find that they do not come with calibration certificates which is a requirement from our client.
Is there any way we can get the certificates (I assume each unit is tested/calibrated prior to despatching).

Andre van der Westhuizen
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Joined: Wed Jul 16, 2014 12:48 pm

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