Detectors with "Self Test"

[big john]

So we're finding more and more situations where it's not possible to do a live-dead-live test when trying to confirm equipment is de-energized.

A lot of non-contact voltage detectors now have a "self test" function that can substitute a live-dead-live test (this is according to the tester instructions). Salisbury, AEMC, Amprobe, and AB Chance all make these types of detectors.

Have any of you guys used these types of testers? Certainly a "self test" is better than no test at all, but I'm not too sure I want to recommend "self testing" take the place of safe-work practices....

Opinions or input?

-John

 

[mcclary's electrical]

So we're finding more and more situations where it's not possible to do a live-dead-live test when trying to confirm equipment is de-energized.

A lot of non-contact voltage detectors now have a "self test" function that can substitute a live-dead-live test (this is according to the tester instructions). Salisbury, AEMC, Amprobe, and AB Chance all make these types of detectors.

Have any of you guys used these types of testers? Certainly a "self test" is better than no test at all, but I'm not too sure I want to recommend "self testing" take the place of safe-work practices....

Opinions or input?

-John

When using a non contact voltage tester, I usually test it by rubbing it through the hair on my arm. If it works on static, I know it's working.

 

[zog]

So we're finding more and more situations where it's not possible to do a live-dead-live test when trying to confirm equipment is de-energized.

A lot of non-contact voltage detectors now have a "self test" function that can substitute a live-dead-live test (this is according to the tester instructions). Salisbury, AEMC, Amprobe, and AB Chance all make these types of detectors.

Have any of you guys used these types of testers? Certainly a "self test" is better than no test at all, but I'm not too sure I want to recommend "self testing" take the place of safe-work practices....

Opinions or input?

-John

The "self" test only check the circuitry of the meter, not the sensing. You need a voltage source (On the same scale as what you are going to test) to propery check the meter is functioning. We use a pizeo-test to verify our meters. http://www.globaltestsupply.com/c/124/Megger_510006_Piezo_Verifier_generates_10_20_and_30_kV.html

 

[zbang]

When using a non contact voltage tester, I usually test it by rubbing it through the hair on my arm.

Almost everybody I know does that, too. Not exactly a proper test, but if the LED lights, something must be OK.

 

[big john]

Almost everybody I know does that, too. Not exactly a proper test, but if the LED lights, something must be OK.

I should clarify: These are medium-voltage detectors, for use on 2.4kV through 25kV.

When I use the pen detectors, I rub those in my hair, too. But I dont think that'll work for the bigger ones.

Zog, thanks for the link, I'll check that out. Seems stupid that some instructions would say you don't have to do a "live dead live" test when their "self test" function doesn't perform a true self-test. Oh, well. :roll:

-John

 

[mxslick]

The "self" test only check the circuitry of the meter, not the sensing. You need a voltage source (On the same scale as what you are going to test) to propery check the meter is functioning. We use a pizeo-test to verify our meters. http://www.globaltestsupply.com/c/124/Megger_510006_Piezo_Verifier_generates_10_20_and_30_kV.html

LOL so how do you test the piezo tester? :grin: I have had piezo ignitors fail before, so who's to say that this tester would either fail to generate any voltage or not generate enough voltage? Even though it may make the click or snap sound, is it really working?

I should clarify: These are medium-voltage detectors, for use on 2.4kV through 25kV.

When I use the pen detectors, I rub those in my hair, too. But I dont think that'll work for the bigger ones.

Zog, thanks for the link, I'll check that out. Seems stupid that some instructions would say you don't have to do a "live dead live" test when their "self test" function doesn't perform a true self-test. Oh, well. :roll:

-John

Big John, I can relate to your dilemma. I was a weapons loader in the Air Force, and one of my tasks was to connect the firing cable to live AGM-65 missiles on the aircraft, while the engines were running and electrical power was on within the aircraft.

We had a tester that we hooked to the firing lead first to verify the firing lead had no voltage. The procedure was to self-test the tester, connect the firing lead to the tester, test the firing lead, if it passed, disconnect the firing lead from the tester, do another self test on the tester and if THAT passed connect the firing lead to the missile.

I stood as far away from the rear end of that missile as my arms would allow and I still got the willies when I connected that lead. Who's to say it didn't get energized in the time it took to re-perform the self-test on the tester?

And who's gonna trust a test box that gets thrown around and was made sometime in the 60's? :roll:

 

[zog]

LOL so how do you test the piezo tester? :grin: I have had piezo ignitors fail before, so who's to say that this tester would either fail to generate any voltage or not generate enough voltage? Even though it may make the click or snap sound, is it really working?

Um, the meter you are testing.

 

[cadpoint]

OK, I'm a box of rocks here (in thought)!

Why are you you using a pin tester on Mid-Level Voltage?

Is it not a fair assumption that a self test is done by the equipment to itself; IE is it not that the equipment QA's itself as to being in as programed as built working order?

 

[mcclary's electrical]

I should clarify: These are medium-voltage detectors, for use on 2.4kV through 25kV.

When I use the pen detectors, I rub those in my hair, too. But I dont think that'll work for the bigger ones.

Zog, thanks for the link, I'll check that out. Seems stupid that some instructions would say you don't have to do a "live dead live" test when their "self test" function doesn't perform a true self-test. Oh, well. :roll:

-John

I did not realize that from your original post. Please ignore my last post

 

[big john]

...Why are you you using a pin tester on Mid-Level Voltage?

We're getting mixed up: The pen testers which are good for 600 volts, I only use on <600 volts. But I was asking about medium voltage non-contact detectors that are good for 69, 122, 345kV or whatever.

Is it not a fair assumption that a self test is done by the equipment to itself; IE is it not that the equipment QA's itself as to being in as programed as built working order?

What I was worried about, and what I think Zog is saying is that these testers do not do a complete "self test". They pick a point in the detector circuit and inject a test signal and I don't know if that point includes the actual "voltage sensing" element.

For example: If you have a Salisbury detector that is supposed to work at 69kV, when you do a "self test" that detector is not injecting a 69kV signal into the sensor to make sure everything works. So it's only "self testing" part of the detector circuit.

Thanks for the replies.

-John

 

[mxslick]

Um, the meter you are testing.

LOL but if the tester is not working right how do you now KNOW that the meter is working right?

Same idea, if the meter gives a good indication but the METER is not functioning correctly...

Of course most test devices like the piezo tester are subject to some sort of calibration or checkout annually or otherwise, right?

Just like the missile tester example I cited in my last post, it is pretty much a matter of taking things with a bit of faith. :grin:

 

[don_resqcapt19]

LOL but if the tester is not working right how do you now KNOW that the meter is working right?

Given the safety issues, you always assume that the voltage generator is working.