Testing of electrical testers

[cwlspark]

The phasing stick that we use, we can test it with the MV megger. I would like to know how one can test the megger the it work and how can I test the the multimeter if it work before I use it for any testing. This is besides the calibration certificate. How regularly must you send your tester for calibration?

 

[IRstuff]

The calibration schedule is usually set by the manufacturer, and is typically something like every 6 months or every year.

As for functional verification, you could easily have a set of standard resistors and so forth. However, the failure rates of instruments like these are relatively low, and there is probably a considerable amount of wasted effort to verify functionality each time you use them. And it's usually pretty obvious when an instrument is no longer functional. The majority of the failures tend to be functional failures, i.e., the instrument doesn't do anything, as opposed to making erroneous measurements. That'll happen, but even then, it would be usually obvious, because it's returning an unexpected answer, and it's at that time that you would go and try to get confirmation of that measurement.

TTFN
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[cwlspark]

Thanks for the reply it's helping alot

 

[waross]

The most critical instance may be testing for the absence of potential before touching electrical parts. It is standard safety practice to test the instrument on a known 'hot' circuit before and after testing the circuit to be worked on.
When I was doing a lot of service work I had a resistor taped to the front of my electronic megger for frequent functionality checks.
A basic check of continuity testers and meggers is to short the leads together before testing to verify the integrity of the leads and test basic functionality.


Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[racookpe1978]

A meggar for testing for energized circuits?

I was always told that a meggar MUST only be used on de-energized ckts, and a voltmeter (multimeter) must be used first to verify the ckt was NOT energized.

 

[IRstuff]

Maybe that's why it needs to be verified for functionality so often ;-)

TTFN
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[Skogsgurra]

You knew it already. But if someone missed it - MEGGER (the Company) makes all sorts of measuring Equipment for Power transmission. Not just insulation testers.

Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

 

[mgtrp]

A meggar for testing for energized circuits?

I was always told that a meggar MUST only be used on de-energized ckts, and a voltmeter (multimeter) must be used first to verify the ckt was NOT energized.

I have heard of people testing CT circuits by removing the earthing link and measuring the insulation resistance, with the CT still in service. I've never tried it myself, and don't think I ever will (if the circuit it so critical that it can't be taken out of service, I would not like to try my luck on it!).

 

[Zogzog]

To get back to the OP's question, hot sticks must be tested every 2 years per IEEE Std 516. There are specific testers available for this. Additionally they must be inspected daily or prior to each use.

Here is some good guidance I suggest you read.

http://www.hubbellpowersystems.com/literature/lineman/br09002e.pdf

 

[cwlspark]

Thanks ZOGZOG for the link very helpfull.