Meter Calibration

[electrics_new]

hi

I was just wondering what the "text book answer" to meter calibration.  I use a METREL Combo meter and have it calibrated every year.  I also have a cal check box and i check it when I get a chance.

Is there a requirement to check your meter if you get it calibrated every year ????

thanks

 

[Andy™]

dont think there is a 'textbook answer', but mines never been calibrated for almost 3 years...

 

[leesparkykent]

your scheme provider might stipulate intervals for using a checkbox between annual calibration if you belong to one.

 

[Manator]

Most of the scam providers like to see a monthly check done on your meters. There is not a requirement to have them formally checked each year unless the companies you test for require this as part of their quality control procedures.

 

[SPECIAL LOCATION]

I suppose best practice guide 7, would be a useful starting point for "industry recognised guidance"..... 

http://www.electricalsafetyfirst.org.uk/mediafile/100346469/Best-Practice-Guide-7-issue2.pdf

However there are a lot of factors that will influence the frequency of verifying the accuracy of test equipment.....

e.g.  consider the exact same make & model of meter used in three different scenarios:-

a)  Shared between a team of 6 guys.. in use every day.

b)  Dedicated instrument only ever used by a single person, in use once a week.

c)  A test instrument for loan by a tool hire company.

There is no text book, one-size-fits-all, solution to the best frequency of calibration and checking procedures to be adopted..

But individual risk assessment of how the meter is used will help define how its accuracy is checked.

Guinness

 

[kerching]

Many many many years ago....before I was even an official Apprentice, we had an analogue Loop tester.theForeman kept it in his van along with THE hand cranked megger.

all i new about the loop tester was that you plugged it in and pressed a button. If the needle did not move very much, or NOT at all, then everything was good. 

it was fubarred....nobody knew!

could have been knacked for ten years!,,,,

 

[New Venture!]

Hand cranked meggar takes me back! First job I ever used one of these on was checking the state of some old three phase motors.

"You need to check the test gear is working before using it" says my caring colleague. "Hold these two clips and tell me if you feel anything.........."

 

[Evans Electric]

Many many many years ago....before I was even an official Apprentice, we had an analogue Loop tester.theForeman kept it in his van along with THE hand cranked megger.

all i new about the loop tester was that you plugged it in and pressed a button. If the needle did not move very much, or NOT at all, then everything was good. 

it was fubarred....nobody knew!

could have been knacked for ten years!,,,,

Again you've reminded me of a similar thing .....back when our only testers were the ...was it ..Newcombe ? insul. & conty. and  clip on ammeters,   a well known switchgear manufacturer's rep. "gave / lent" us  one of their impedence testers , it was huge , it was digital, it had reallly thick leads with insulated screwdown clamps for BBs  or onto lugs , usually live .

This was a time when the only testing carried out was if the Clerk of Works insisted , so mainly schools & hospitals .

It was only when we had actually gone bust , last job was a new local depot for British Gas , boss asked if I'd just meet the big-wigs there and take the Ze reading in their presence.

Clamped it on ,    400A supply ,  hit the button ....0.2 ohm ...then it dawned on me , every job we'd ever tested was 0.2 .  It was duly noted down and as they all left to have an expenses paid for lunch,  I left to sign on at the so- called Job Centre.

 

[kerching]

I think ours defaulted to 0.1!

as i sadi before...nobody knew what the reading meant anyway!

 

[Evans Electric]

Ah for those halcyon days ....put test lamp L to E.....lights up , its earthed!     (And there,s no RCD to trip on L-E  either)  

 

[Tony S]

How did you test the early RCDs

 

[Andy™]

test button and stopwatch

 

[kerching]

Test button and Calendar! 

 

[Evans Electric]

First ones were the voltage operated ones ,  so as Kerch said,  test button & calendar .

As the RCDs came on the scene it was test button & sometimes the Drumond mains tester   L - E .

 

[Tony S]

First ones were the voltage operated ones ,  so as Kerch said,  test button & calendar .

As the RCDs came on the scene it was test button & sometimes the Drumond mains tester   L - E .

The first RCCD I fitted back in 1975 was 500mA it cost £65. The Drumond test lamp wouldn’t bother it, a 100W lamp made it trip.

30mA RCCD’s were available if you had an arm and a leg to spare.

 

[steptoe]

And why is it, even now, when you ask for a 100mA TD in some wholesalers they look at you like you had asked for the moon on a stick,!? 

I even had one place, eddys, try to tell me Merlin Gerin didn't make one, I had to take the part number in to them,! :shakehead

 

[Evans Electric]

I seem to remember Chilton was it ?, they used to do ELCBs as they were called ,  Voltage not current , always supplied in enclosures that were far too small.

 

[Tony S]

They looked almost identical but you are right about them being Chilton. Trying to get 16mm² in to them was a nightmare. The clamp terminals were at the wrong angle for the terminal cover cutouts.

Take one to bits and admire the construction, 60A? I’d lay money on them happily handling twice that.

NOTE Made in France  :facepalm:

 

[phil d]

Ah for those halcyon days ....put test lamp L to E.....lights up , its earthed!     (And there,s no RCD to trip on L-E  either)  

Oh yes,earth testing with a Drummond as you say and a Megger, if you were lucky,how did we survive without all the modern test gear,and how come more stuff didn't burn down?lol

 

[kerching]

Oh yes,earth testing with a Drummond as you say and a Megger, if you were lucky,how did we survive without all the modern test gear,and how come more stuff didn't burn down?lol

Simples.......proper electricians, proper training, proper everything....no Chinese carp.  Also strong wrists!