What Happens During Meter Calibration

[Boing89]

as some of you know my background is as an electrician in the RAF mainly working on 3 phase machines including generators. When it comes to meter calibration they are always done and any meter found to be out of calibration is quarantined until it’s been done.

My new employer seems much more cavalier. My supervisor was told 3 weeks ago the Fluke he’d provided was about to go out of calibration at the end of November. Here we are on the 13 Dec and I’ve spent the week fault finding with it on 690v equipment still out of calibration.

Now for the type of tests I was doing I don’t need it to be pinpoint accurate. Is there voltage or not? Is there continuity or not? Despite that I’m still uncomfortable using it right now.

I have to admit to not really knowing what happens when they go for calibration. Is it also a safety check for instance or is it purely making sure it reads correctly? Is it standard as a civilian to calibrate your equipment or is it more one of those things you should do and probably will when you get around to it?

I’m trying to gauge how hard I want to push this with him.

 

[telectrix]

to comply with BS7671 and scams like niceic, all meters should be calibrated annually. this entails checking them for accuracy on all scales. i always wait for a wholesalers free cal. day and get mine done with free bacon bap and coffee thrown in. sometimes i may even buy someting.

 

[mattg4321]

Last wholesaler calibration day I overheard the manager say all the instruments presented passed. That was around 100 test instruments. None of which required 're-calibrating'. Money for old rope imo. I know if my meter isn't working properly. If it starts throwing out funny results I'll soon notice.

In other words don't worry about a few weeks.

 

[telectrix]

never once had my 1980's AVO 8 or wind up Megger calibrated. they both still work perfeck.... as a laff. i had the AVO 8 calibrated earlier this year. it passed.

 

[Gavin John Hyde]

From what i understand a reputable calibration outfit will check it against known and stable measurements to see what it gives out, if the mft is out of the accepted range then i understand they can plug something in or open it up and connect a lead to calibrate it. I believe that this stuff comes from the major makes of mft such as kewtech, fluke, megger etc. they also make available to the calibration centres hidden functions that are accessed to change readings.
kewtech have a good tech guy called alan towler who told me how to adjust my loop readings at low values via hidden menus as they were hit or miss.
I have a ketwech fc2000 check box at home that i can check continuity, insulation, loop and rcd tests on. once a month or more i will check it and then record on the form i have. get it out come annual assessment. it helps to keep an eye on things

 

[telectrix]

i check my IR function using 'er inddoors. 500V, press test button. if she wakes up, it's working.

 

[Boing89]

i check my IR function using 'er inddoors. 500V, press test button. if she wakes up, it's working.

To be fair that’s one of my biggest worries, it’s got an insulation test function as well. Am I going to push the button and it’s the meter insulation that breaks down? That voltage stings

It sounds like I’ve nothing to worry about (apart from site Quality reps) so I’ll continue probing away.

 

[Rpa07]

It shouldn’t really cost as much as it does in my opinion but I guess that they have to justify how crucial the work they do is! much like the schemes justifying their recompense!

 

[Strima]

to comply with BS7671 and scams like niceic, all meters should be calibrated annually. this entails checking them for accuracy on all scales. i always wait for a wholesalers free cal. day and get mine done with free bacon bap and coffee thrown in. sometimes i may even buy someting.

If you carry out monthly checks using calcard, or similar, and do RCD testing on the same RCD and the results are recorded they're happy for the calibration to be done every three years.

 

[Stspark]

Nothing specifically in BS7671 states an annual calibration is required. However to comply with requirements of EAWR. GN3 and GS38 contain requirements to ensure your test equipment is maintained and accurate by regularly checking readings against known values. Or for simplicity and cost effectiveness an annual calibration is prudent.

 

[telectrix]

i had me hammer calibrated against an apprentice's skull. it failed as it took 3 hits to put him down , the pass mark is 2.

 

[PEG]

i had me hammer calibrated against an apprentice's skull. it failed as it took 3 hits to put him down , the pass mark is 2.

Is this the apprentice you had,that kept chopping your broomstick,and multiplying it,binary style?

 

[Shoei]

...Is it standard as a civilian to calibrate your equipment or is it more one of those things you should do and probably will when you get around to it?

I’m trying to gauge how hard I want to push this with him.

Good question, it generally figures in ISO9000 procedures for businesses with ISO registration. Calibration is expected to validate any processes where the kit is used. So a PAT tester (say) would be expected to have a current calibration certificate. You can identify kit that doesn't need to be calibrated, for example an oscilloscope where you're just looking for a waveform or the like, you can put an 'indication only' label on it and if that does what's necessary it's fine.

 

[Edtwozeronine]

Big Clive recently just tested his by putting it over a 1000 ohm resistor in his latest video. That wasn't the point of the video, he just wanted to make sure it was ok after some odd readings.

 

[stevethesparks]

I used to (wrongly) think that a calibration would include a tweak to keep things spot on. After looking up the word "calibration" I found it meant that equipment was only being checked against a known reference. What a rip-off..

 

[snowhead]

After looking up the word "calibration" I found it meant that equipment was only being checked against a known reference. What a rip-off..

The known reference has to be checked for calibration and whatever is used to check the reference has to be calibrated etc.
The higher up the system you go the more accurate the check instruments have to be.
Every calibrated piece of equipment has to be traceable back to a National or in our case probably a European Standard.
Add to that, the people doing the testing would have to be regularly checked to make sure they are following the procedures correctly.

 

[Risteard]

None of which required 're-calibrating'.

It's actually not re-calibrating but adjustment.

Calibration is verification that it is reading accurately and is not about making changes to it if it isn't. This is adjustment.

 

[oracle]

never once had my 1980's AVO 8 or wind up Megger calibrated. they both still work perfeck.... as a laff. i had the AVO 8 calibrated earlier this year. it passed.

Do you think my bell and battery tester for continuity and hand cranked telephone generator will pass?

The bell still rings and the generator is hard to crank if the insulation resistance is really low.

 

[oracle]

never once had my 1980's AVO 8 or wind up Megger calibrated. they both still work perfeck.... as a laff. i had the AVO 8 calibrated earlier this year. it passed.

Do you think my bell and battery tester for continuity and hand cranked telephone generator will pass?

The bell still rings and the generator is hard to crank if the insulation resistance is really low.

 

[l4urence]

@Boing89 Hey! Ex RAF here too! If the values of the measurements are being recorded for certification the meter should be in calibration - the values are not valid without it - it's a requirement. I also use a Calibration Card before testing, takes 2 mins and confirms nothing amiss since calibration was carried out.