Calibration checksheet

[ISSWWW]

Kewtech print a Checkbox log book to record the instrument and the regular checks made, it is quite inexpensive at around

 

[initforthemoney]

So you only check the accuracy once per year? That worries me. Could be wrong for 364 days.

Assuming are we?? Now you know thats not allowed on here.

How often does your "equipment" have to be checked?

Anyway, I never said that i only check them once a year.

I said that my meters get calibrated EVERY year at a reputable company.

I also keep an eye on them with a checkbox but i do not rely on it totally.

 

[philbas]

I think the MOT analogy is a good one.

Once a year I have to put my car through an MOT, but on a weekly basis I check my tyre pressures and oil level etc.

Some people dont bother to do this and rely on the MOT.

So oil, tyres etc get checked once a year.

Is the car safe, maybe, or did you get a puncture the day after the MOT ?

Any check is only valid at the point it was made, the checksheet is the equivalent to checking your tye pressure once a week. It may not be the same as a full MOT but at least your checking to see nothing has gone seriously wrong.

 

[batty]

[quote name='Andy

 

[batty]

its not an NIC thing,the law simply states you should have accurate test equipment and a method of showing it is accurate.

try looking after your kit in future.

its usually a good idea to select the correct range before blaming the manufacturer.

I can assure you Steptoe that I have been testing long enough to know what range I need to select when testing.

 

[bryn]

I discussed this with Elecsa and they are happy to accept your own calibration records and a freind of mine who is with NIC does the same and they accept it.

have sent you a PM if you send me mail address will e-mail you one that I use which Elecsa are happy with.

 

[milovisk]

I know that certain parts of Elecsa , NIC , Napit etc will accept your own calibration records but if you speak to anyone at the top of the organisation it is not what they say and as you can see from one of my other posts it is not what NICEIC say on their website.

To me this basically says that if anything ever went wrong then I doubt very much that the relevant body would back the individual contractor, as with any standard it is the individuals responsibility to comply and not the assessing body, they are there to facilitate and as far as "practicably possible" ensure that you are in compliance with the standard.

In my opinion (and in others at the bodies if you speak to the people higher up) it is not acceptable to self check only because of the following reasons (I use the word check rather than calibrate as using a checkbox is not a calibration)

1. It does not check every range on the meter

2. It does not check that the meter is compliant with the standard

3. It is totally open to abuse

4. It is not being used in the way it was originally set out

I will enlarge on points 3 & 4 in a moment but if anything ever went wrong with an installation , a fire etc, and an independent auditor found out that the installation had been checked with a 5 year old meter that had been checked on a handful of cheap resistors and a standard socket , had no current calibration certificate and the meter was non compliant then do you think that this would stand up well if further action was taken? I personally don't and I don't think that NICEIC would back you either in this instance as they would refer back to their documentation on their website and on the manuals for their checkboxes.

Going back to point 3 , I have seen many test sheets not filled in for months and contractors who openly find it funny to say I just fill them in the week before I have my inspection. I am not saying the majority do this but a minority will take advantage as in any other walk of life and regs are always there to protect the majority from the minority.

Also on point 4 , it was originally set out by the relevant bodies that if you get your meter calibrated then immediately afterwards start to record the results on a propietary checkbox or by comparison to a known good standard then you could possibly extend your calibration period to 2 years. I personally don't agree with this but at least it did have some logic.

What happens now is that someone who has not got a current certificate can buy a checkbox and start checking himself and some inspectors are accepting this which again is totally wrong and dangerous for the individual in the event that something ever goes wrong.

I would personally treat it like an insuarance policy and calibrate and self check in between to be seen to be doing everything that is practicably possible to ensure my meter was upto standard, it costs aroud

 

[m4tty]

Milovisk good reply.

 

[steptoe]

at my last assessment the assessor (we are NICEIC AC) actually stated that yearly cal was NOT a requirement,

especially as we have 3 meters that are checked on a rig monthly and any discrepancies woul;d immediately be obvious in either the checkbox or meter,

it would be one mighty coincidence for all 3 meters and checkbox to deviate by exactly the same amount.

 

[Michelle2909]

I think the MOT analogy is a good one.Once a year I have to put my car through an MOT, but on a weekly basis I check my tyre pressures and oil level etc.

Some people dont bother to do this and rely on the MOT.

So oil, tyres etc get checked once a year.

Is the car safe, maybe, or did you get a puncture the day after the MOT ?

Any check is only valid at the point it was made, the checksheet is the equivalent to checking your tyre pressure once a week. It may not be the same as a full MOT but at least your checking to see nothing has gone seriously wrong.

The Analogy of comparing calibration to an MOT test if that was correct would leave a lot to be desired, as we all know you could put a car into half a dozen different mot stations and get different results. a pass in one can be failed in another and a fail in one can pass in another.

The other major difference is MOT is a Legal requirement, Calibration IS NOT

Its just Firms with their own Agenda trying to make it appear so.

 

[milovisk]

at my last assessment the assessor (we are NICEIC AC) actually stated that yearly cal was NOT a requirement,especially as we have 3 meters that are checked on a rig monthly and any discrepancies woul;d immediately be obvious in either the checkbox or meter,

it would be one mighty coincidence for all 3 meters and checkbox to deviate by exactly the same amount.

May I ask how often you or your assessor check that the meter totally complies with the requirements of the regulations.

Do you do all of the checks that are outlined in my detailed posts above, it is not about base accuracy, that is probably the least of your worries.

 

[milovisk]

The Analogy of comparing calibration to an MOT test if that was correct would leave a lot to be desired, as we all know you could put a car into half a dozen different mot stations and get different results. a pass in one can be failed in another and a fail in one can pass in another.The other major difference is MOT is a Legal requirement, Calibration IS NOT

Its just Firms with their own Agenda trying to make it appear so.

Yes we do calibrations as do other people on this forum , we have not hidden that fact and need to make a living just like everyone else here needs to make a living.

The above is rather like me saying "I don't care about qualified electricians coming to do a professional and certified installation in my house, to hell with the regs I'll do it myself"

You are quite correct that calibration is not a legal requirement but it is a requirement to comply to regulations, it quite clearly states in the regs what the minimum performance that is expected from your testers so as such it implies that you need to prove this on an ongoing basis. Self checking does not do this, it provides spot checks of base accuracy.

It has also long been a requirement that instruments are traceable to national standards, this cannot be achieved in any industry if calibration is only performed outside the manufacturer recommended limits. For the type of testers you use and for checkboxes this is 12 months.

Has anyone dared to ask their NICEIC inspector why they say otherwise on their website and why their checkboxes state quite clearly that calibration is required every 12 months? Seems like some contradictions going on to me.

Not good - not good at all.

 

[steptoe]

May I ask how often you or your assessor check that the meter totally complies with the requirements of the regulations.and how often does a calibration centre send their meters for calibration?

it must be every other week I suppose due to the number of other people depend on you having calibrated meters to test with,

Do you do all of the checks that are outlined in my detailed posts above, it is not about base accuracy, that is probably the least of your worries.

quite right,

I worry more about ill informed people doing p*** poor jobs and suckers like me having to go sort them out.

its usually misinformation and a couldnt care less attitude as long as I get my money I will say and do and convince people anyhow I can just to get the work.

Yes we do calibrations as do other people on this forum , we have not hidden that fact and need to make a living just like everyone else here needs to make a living.The above is rather like me saying "I don't care about qualified electricians coming to do a professional and certified installation in my house, to hell with the regs I'll do it myself"

You are quite correct that calibration is not a legal requirement but it is a requirement to comply to regulations, it quite clearly states in the regs what the minimum performance that is expected from your testers so as such it implies that you need to prove this on an ongoing basis. Self checking does not do this, it provides spot checks of base accuracy.

what regs would that be?

It has also long been a requirement that instruments are traceable to national standards, this cannot be achieved in any industry if calibration is only performed outside the manufacturer recommended limits. For the type of testers you use and for checkboxes this is 12 months.

Has anyone dared to ask their NICEIC inspector why they say otherwise on their website and why their checkboxes state quite clearly that calibration is required every 12 months? Seems like some contradictions going on to me.

but they dont make the rules, do they?

Not good - not good at all.

 

[milovisk]

What regs would those be

8.7.1 - Basic requirements

Guidance Note 3 - Inspection and Testing - makes it clear that instrument accuracy is required to be at least that shown later in this sub-section for the various types of instrument. Regular recalibration using standards traceable to National Standards is now required, together with checking after any incident which has involved mechanical mishandling. Many electrical installers will not be used to sending their instruments regularly for recalibration, but must now do so. Guidance Note 3 is not specific on the time intervals at which recalibration must be carried out, but it would seem sensible for occasionally used instruments to receive attention every two years, whilst those used frequently are likely to need recalibration annually.

If installations are to be tested to show that they comply with BS 7671, the following instruments will be necessary. After the name of the instrument are brief notes which may be helpful in choosing a new instrument or in deciding if one already to hand will be satisfactory. The first four instruments listed are absolutely essential for all tests, although the low resistance tester and the insulation resistance tester may be combined in a single instrument. An instrument which can test continuity, insulation resistance, earth-fault loop impedance and the operation of RCDs is available from many manufacturers, and will save a great deal of time in changing instruments and test leads - even more time can be saved with an instrument which will save the test results for downloading to a computer. The last two instruments will not often be required on simple installations, since applied voltage and earth electrode resistance tests are often not needed. All instruments used should conform to the appropriate British Standard safety specification (BS EN 61010 for electronic types, and BS 5458 for electrical instruments). Test leads, including prods and clips, must be in good order and have no cracked or broken insulation. Fused test leads are recommended to reduce the risk of arcing under fault conditions.

The basic accuracy of +5% quoted below is for digital instruments. Analogue instruments should have an accuracy of +2% at full scale deflection, which will give the required accuracy of +5% over the useful part of their scales.

Low resistance ohmmeter

Instruments to BS EN 61557-4 will comply.

Basic instrument accuracy required is +/- 5%

Test voltage ac or dc, between 4 V and 24 V

Test current not less than 200 mA

Able to measure to within 0.01 ohms (resolution of 0.01)

May be the continuity range of an insulation resistance tester.

Insulation resistance tester

Direct test voltage depends on the circuit under test, but will be:-

250 V for extra-low voltage circuits

500 V for other circuits supplied at up to 500 V

1000 V for circuits rated between 500 V and 1000 V.

Must be capable of delivering a current of 1 mA at the minimum allowable resistance level, which is:-

250 kOhms for the 250 V tester

500 kOhms for the 500 V tester

1 MOhms for the 1,000 V tester

Basic instrument accuracy required is +/-5%

Must have a facility to discharge capacitance up to 5 microF which has become charged during the test

May be combined with the low resistance ohmmeter

Earth-fault loop impedance tester

Instruments to BS EN 61557-2 will comply

Must provide 20 to 25 A for up to two cycles or four half-cycles

Basic instrument accuracy required is +/-5%

Able to measure to within 0.01 ohms (resolution of 0.01)

Instruments to BS EN 61557-3 will comply

Residual current device (RCD) tester

Must perform the required range of tests (see (8.6.3))

Suitable for standard RCD ratings of 6.10, 30, 100, 300 and 500 mA

Must NOT apply full rated test current for more than 2 s

Currents applied must be accurate to within +/-10%

Able to measure time to within 1 ms (resolution of 1)

Must measure opening time with an accuracy of +/-5%

 

[steptoe]

pleas remember GN3 is exactly that, it is NOT a statutory document AFAIAA.

and how often do you send your meters away to be calibrated by an independent source?

after all, think if you even only do 10 meters, multiplied by 364 days = 3640 installations to be tested wrong, at one periodic or new installation a day, sometimes I will test 3 or more shower circuits in one day, so I guess there could be thousands of people with a dangerous shower because I didnt have a checkbox and instead relied on some calibration company with a dodgy meter to give me a printout saying my meter was OK cos their uncalibrated meter said so.

 

[steptoe]

Guidance Note 3 is not specific on the time intervals at which recalibration must be carried out

says it all really.

 

[SPECIAL LOCATION]

Guidance note 3

Chapter 4

Test Instruments

Page 81

Section 4.2 Instrument accuracy

Point 2 Loss of Calibration:

Instruments should be regularly re calibrated using standards traceable to national standards, or have their accuracy cross-checked using know references such as comparing readings to those obtained by other instruments, or by the use of a proprietary instrument 'check box' having clearly defined characteristics.{next paragraph and over to page 82.}

In all cases the type and frequency of recalibration or checking required should be as specified by the instrument manufacture taking into account ambient environmental and usage factors as appropriate. For example, if an instrument is left stored in a constant temperature in a dry environment for long periods and is used infrequently, the user may be able to extend the recalibration interval. However if an instrument is roughly handled and is regularly stored in vehicles and hence is subject to fluctuations in temperature and humidity caused by changes in time of day/night and time of year then more frequent confirmation of accuracy would be appropriate.

So the general guidance to electricians working to BS7671 would IMHO be:-

Calibration is important and you need a calibrated instrument as a starting point.

With a known good calibrated instrument do some cross reference checks with other instrument(s) and/or a proprietary check box.

Keep regular rechecks to the reference sources preferable each day you use the test instrument.

Any signs of deviations or damage get the instrument re-calibrated.

The interval for formal calibration will be based around Manufactures guidance, frequency of use, storage and handling methods, availability and frequency of regular cross checking to other instruments - check-boxes.

Reasonable assumptions and/or points for consideration:-

• Generally a test meter purchased by a sole trader for his/her own personal use, will be well looked after and infrequently used.
  
• A test meter with shared use in a small to medium sized business is probably NOT purchased by the user and is going to be less well looked after and more frequently used.
  
• From statistics given in post #20, when sending meters for calibration, "Usually between 10 - 15% need some form of intervention" so typically 85% to 90% do not need any adjustments and are still within their tolerance spec's.
  

So it is quite reasonable to assume if you are undertaking regular cross reference checks AND you are looking after your own meter, quite probably an annual recalibration interval could be extended to 2 years, or possibly more.

At the end of the day it is the person signing the certificates who will have to make the call as to if he/she has confidence that the readings they are getting are accurate.

PERSONALLY..

I wouldn't be happy with a re-calibration interval greater than 2 years.

I have my meters re calibrated by an on-site service..

Meters calibrated at my home..

No posting off waiting extra days for delivery schedules..

Last visit 2 meters cost

 

[Michelle2909]

Yes we do calibrations as do other people on this forum , we have not hidden that fact and need to make a living just like everyone else here needs to make a living.Not good - not good at all.

You seem to have taken this personally, this was not a personal statement about you or anybody else on this forum it was a general comment about firms, although maybe It could have been worded better, Vested interest would probably have been more appropriate than hidden agenda.

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Yes we do calibrations as do other people on this forum , we have not hidden that fact and need to make a living just like everyone else here needs to make a living.Not good - not good at all.

Not by giving an incorrect impression to customers, that would be like us giving customer the impression that a pre 17th edition consumer unit is unsafe.

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The above is rather like me saying "I don't care about qualified electricians coming to do a professional and certified installation in my house, to hell with the regs I'll do it myself"Not good - not good at all.

Not the same at all as its not a legal requirement to be a qualified electrician, you can Legally do Notifiable work yourself as long as you go through Building control or a part P scam Provider

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The above is rather like me saying "I don't care about qualified electricians coming to do a professional and certified installation in my house, to hell with the regs I'll do it myself"Not good - not good at all.

Also not the same. as certification is a legal requirement of Building control

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You are quite correct that calibration is not a legal requirement but it is a requirement to comply to regulations, it quite clearly states in the regs what the minimum performance that is expected from your testers so as such it implies that you need to prove this on an ongoing basis. Self checking does not do this, it provides spot checks of base accuracy.Not good - not good at all.

It is not requirement Legal or otherwise to comply with the Regs in fact it is actually permissible to deviated from the regs, Its down to our professional judgment. most professional electricians have deviated from the regs at some time or other

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Has anyone dared to ask their NICEIC inspector why they say otherwise on their website and why their checkboxes state quite clearly that calibration is required every 12 months? Seems like some contradictions going on to me. Not good - not good at all.

Is it not very coincidental that they have changed to this since they have been associated with a calibration house, vested interest/hidden agenda springs to mind.

 

[Michelle2909]

milovisk I presume from your reply to a previous post of mine that you are involved in calibration testing. if so maybe you can answer this question

Do you calibrate to the Manufactures Calibration procedures or just to the manufactures Specifications.

if you are not testing to the Manufactures Calibration Procedures Were do you get the specification that you use for your cal purposes from,

ie. direct from the manufacture, From their Advertisement specification sheet or from the user manual ect.

Also if a manufactures calibration procedures involve optimization/Adjustment of the EUT

Does yours include that in your calibration process.

Answers to this would also be appreciated from any other cal houses/reps/employees.

 

[milovisk]

pleas remember GN3 is exactly that, it is NOT a statutory document AFAIAA.and how often do you send your meters away to be calibrated by an independent source?

after all, think if you even only do 10 meters, multiplied by 364 days = 3640 installations to be tested wrong, at one periodic or new installation a day, sometimes I will test 3 or more shower circuits in one day, so I guess there could be thousands of people with a dangerous shower because I didnt have a checkbox and instead relied on some calibration company with a dodgy meter to give me a printout saying my meter was OK cos their uncalibrated meter said so.

They are cross checked every morning and night with primary standards and are calibrated every 6 months to UKAS standards at a cost probably 10 times that of buying a brand new checkbox.

As I quoted above and has been subsequently reiterated in another post "traceabilty to national standards" is the key.

Traceabilty is only valid to the length of your certification i.e. 12 months.

Cross checking and using non-traceable checkboxes does not fulfill this requirement.