Calibration of secondhand test equipment

[Donkmeister]

Right, I'm doing my own rewire and I need to know how to calibrate my neon screwdriver for insulation test. I plan to use the second hand of my watch to check RCD disconnect times.



Sorry, couldn't resist!

In actual fact I am doing my own rewire, as a DIYer, and am working out my test strategy before submitting my Building Notice. An all-in-one tester appears to be about £400 new, can't really justify that so am looking to buy secondhand.

If I buy a 5 year-old Megger or Fluke, assuming it doesn't have a current certificate, what is a typical price for getting it calibrated?

Looking on the BS7671 installation certificate, there is nowhere to include evidence that the kit was in calibration at the time of testing, just the name of the kit (top right of "Form 4" on the certificate). Does that mean calibration is a "nice-to-have", and it is assumed that test kit will be near-enough throughout its service life?

 

[flameport]

Calibration is important, particularly with an unknown piece of equipment which is several years old. If it was providing wrong readings, how would you know?

However for only one job, hiring the required equipment will be far easier, and probably cheaper.

 

[echoes]

Last time I got the model forms 2 years ago there was a space to put the calibration cert number at the top of the test schedule, but it's gone on the latest form on the IET website

Does that mean calibration is a "nice-to-have", and it is assumed that test kit will be near-enough throughout its service life

I guess if there was any legal case where you had to prove that you tested it in accordance with BS7671, then without a calibration certificate, how else could you defend your instrument's measurements?

However if building control are satisfied with the EIC form and in doing so issue a completion certificate without evidence of calibration, then presumably, job's a good 'un.

EDIT: The cost of hiring a tester would not be that much more than paying for calibration, and certainly much less than a second-hand tester + calibration

 

[echoes]

how to calibrate my neon screwdriver for insulation test

Use a large club hammer.

 

[Donkmeister]

Echoes, I'm glad it's not just me - I thought I was going mad trying to find the place to write "I didn't just look at the equipment, it was bright yellow so I thought it looked accurate enough". As someone who has worked with various sorts of test equipment in the past, it feels wrong to be allowed to write a value without min/max errors or a calibration certificate.

Hiring equipment sounds like a good bet, but my usual local places don't have electrician's equipment for hire... anyone know of a place that can hire this sort of stuff out?

Maybe it would be cheaper to pay a spark to come and test the installation, but that seems like asking a spark to sign off my work... Sounds dodgy, any thoughts/experience on that?

 

[Donkmeister]

Calibration is important, particularly with an unknown piece of equipment which is several years old. If it was providing wrong readings, how would you know?

Exactly, what if I run an insulation test and the equipment says 40M ohms but really it's shorting somewhere?

The mad thing is that the certificate doesn't give you anywhere to record such information. Perhaps they assume that anyone who can sign off their work would have their equipment calibrated frequently enough.

 

[LiamPope]

Out of interest - have Bedford agreed they will accept an EIC from you with you carrying out the testing yourself? Do they require any evidence of your 'competence' to do so?

I've done a DIY rewire too and have access to test equipment. Several months ago I was in the process of agreeing this when everything went silent just about the time the councils merged (or whatever big shakeup happenned anyway). About time to get back in touch as the rest of the stuff on my building notice is done so I wouldn't mind some paperwork for what it's worth. Who are you speaking to there, if you dont mind me asking? I wonder if there policies have changed in light of the restructuring and/or the new rules on charging for testing? They were previously one of the LABCs refusing to pay for testing of DIY notified work (at the time they were supposed to), hence me taking the angle of trying to get them to accept the EIC from myself on the back of my leccy engineering degree - tenuous I know

Liam

 

[Donkmeister]

Who are you speaking to there, if you dont mind me asking? I wonder if there policies have changed in light of the restructuring and/or the new rules on charging for testing? They were previously one of the LABCs refusing to pay for testing of DIY notified work (at the time they were supposed to), hence me taking the angle of trying to get them to accept the EIC from myself on the back of my leccy engineering degree - tenuous I know

Liam

Last time I spoke to them was after the merger. My degree is in Physics, but I have a professional background is in aerospace engineering.

Talking to their BCO who dealt with electrics over the phone (over at Chicksands), I explained that I have professional experience of designing and working with systems of dc and ac at 50, 60 and 400Hz, voltages ranging from the ELV to HV range, 1, 2, 3 and 12 phase, along with the testing and proving of such systems.

His response was "Sounds like you'll be fine to issue the installation certificate, put all your professional experience in a letter when you submit your Building Notice. Part P is in place to stop someone who doesn't understand electrics from buying a roll of twin-and-earth at B&Q one Saturday with the intention of rewiring their house on a Sunday.". They explained they would want to inspect at first fix, but would want me to issue the BS7671 certificate.

That is Central Bedfordshire, if that makes any difference to your situation.

Have you tried giving them a photocopy of your degree certificate? My "competence" is harder to prove as it is not written on an official certificate (wish I'd gone for chartership now!) but I can give dates and the bodies who employed me if they want to check it up.

 

[echoes]

...anyone know of a place that can hire this sort of stuff out?

Not out of experience, but a google for "17th edition tester hire" brings up quite a few places that will hire calibrated testers. Maybe one of the regulars will have a good recommendation?

Maybe it would be cheaper to pay a spark to come and test the installation, but that seems like asking a spark to sign off my work... icon_eek.gif icon_confused.gif Sounds dodgy, any thoughts/experience on that?

If you can find one who is willing to sign off your work, like he's not supposed to!

I's be interested to hear the outcome of your testing and who the LABC descide should do it. My experience of this has not been entirely happy, with an LABC inspector first insisting that I should test, then saying they were appointing a new contractor to do testing etc etc. It dragged on for months.

 

[ricicle]

On the top of the schedule of test results where you note down the tester, include it's serial number and then attach a copy of the calibration cert with the sheets.

 

[FDJ]

1, 2, 3 and 12 phase,

WOW, that beats me, I have only ever seen 6 phase!

Frank

 

[ban-all-sheds]

You should take more water with it.

 

[Risteard]

Last time I got the model forms 2 years ago there was a space to put the calibration cert number at the top of the test schedule, but it's gone on the latest form on the IET website

No, it's the serial number of the meter that goes on the forms. Therefore it is traceable.

 

[Donkmeister]

You should take more water with it.

Water? And 12-phase?

 

[slup]

His response was "Sounds like you'll be fine to issue the installation certificate, put all your professional experience in a letter when you submit your Building Notice.

For what it's worth, my LA said the same. "If you believe you are 'competent', then submit the EIC along with a covering letter justifying why you feel you are 'competent'..."