Neon screwdrivers!!

[monkey5]

evening all

i know its a no no to use a neon screwdriver to test but im not 100% sure why this is. the reason i ask is that ive been to check out a faulty light, when i got there he said he'd check for power with his tester (neon) and it lit up, i recommend he didnt use it for that but more for a screwdriver and he asked why? i blagged it, but would like to know the reasons for next time.

thanks wayne

 

[lvukol]

The old neon screwdrivers would fail open therefore you would act as a nice earth hence a lovely electric shock. Thats there the no no comes from. The new ones apparently are tested to fail closed (acts like a fuse) so that you wont get a shock, I personally don't trust them and think they should be banned, but each to there own.

 

[NozSpark]

Because it uses you as part of the circuit and gives no actual indication of the amount of voltage present..

 

[monkey5]

Because it uses you as part of the circuit and gives no actual indication of the amount of voltage present..

basically what i said, but his answer was well why do they sell them then!

that i couldnt answer and agree with Ivukol that they should be banned.

 

[lvukol]

Down to the use and the way its used is what the manufacturer will argue. In my experience if I'm testing someones work and I spot a neon screwdriver in there tool box, I'm usually inclined to double check everything. It's a fool proof way of spotting a rookie or someone with a death wish.

 

[Subneural]

I spot a neon screwdriver in there tool box, I'm usually inclined to double check everything. It's a fool proof way of spotting a rookie or someone with a death wish.

I like neon screwdrivers, The have nice little clip on the top you can hang them outside your pocket with ROTFWLROTFWLROTFWL

 

[Andy™]

The old neon screwdrivers would fail open therefore you would act as a nice earth hence a lovely electric shock. Thats there the no no comes from. The new ones apparently are tested to fail closed (acts like a fuse) so that you wont get a shock, I personally don't trust them and think they should be banned, but each to there own.

opposite way, if they fail closed, you have low/no resistance in screwdriver, and it will be like touching a live wire. if it fails open, then its extremely high resistance, will tell you something is dead, and then you will be when you touch it.

some testers (like fluke T140 & other models) can tell you if its live even without a neutral/earth reference. just touch the main probe to a live and it will beep. needs another reference to give you a voltage reading though

 

[Mr Sworld]

Neon screwdrivers don't 'fail safe'! Come on! There are plenty of of 'non contact' testers out there nowadays!

Still, the only way to test properly is a multimeter or a test lamp!

 

[SPECIAL LOCATION]

evening alli know its a no no to use a neon screwdriver to test but im not 100% sure why this is. the reason i ask is that ive been to check out a faulty light, when i got there he said he'd check for power with his tester (neon) and it lit up, i recommend he didnt use it for that but more for a screwdriver and he asked why? i blagged it, but would like to know the reasons for next time.

thanks wayne

Excluding all the 'fail safe' 'fail dangerous' points that the other guys have already debated quite admirably..

Lets assume you have a good working Neon.

AND it IS a type that will fail safe..

It is still unreliable because of the "brightness question"

a] You need to ask yourself:-

(i) What Voltage does the neon require in order to illuminate?

(ii) What voltage is considered to be safe, and thus at what point does a

voltage become hazardous?

How do you know what you are reading with a neon?

{Spec Loc scientific test method coming up...... ] :coat}

b] How can any item of safety test equipment be conditional upon what you are wearing!

METHOD

• Wire yourself up a little light switch dimmer circuit with a suitably accessible live part on the load side. Plug it in, in a garage or room with a concrete floor.
  
• Take your boots off test the circuit with your neon whilst standing on the concrete floor in just your socks
  
• Twiddle the dimmer up and down a bit watch how the brightness off the neon changes.
  
• Do the above two points again.. but this time whilst wearing your "approved safety shoes", those with 1000v rated insulated soles, (NOT trainers, proper safety boots).**
  
• If you are really keen, you could also do the test whilst standing on fibreglass insulated step ladders! :|
  
• Try all of the above again in a environment with high ambient background light and/or bright sunshine!
  

CONCLUSIONS

Compare the difference with the "apparent glow" of the neon, which varies depending upon what you are wearing or what you are standing on! Thus the Neon is an inconstant measuring device that cannot provide a reliable safe/dangerous voltage level indication.

If you try the same tests with an approved meter or voltage tester incorporating a voltage level indication, shoes socks, floor contact has NO effect upon the results you read off the meter.

{** as a side point do an insulation resistance test on the sole of proper safety boots compared to trainers, note the difference in conductivity}

 

[SPECIAL LOCATION]

Neon screwdrivers don't 'fail safe'! Come on! There are plenty of of 'non contact' testers out there nowadays!Still, the only way to test properly is a multimeter or a test lamp!

Concurances in abundance Mr S!Applaud Smiley:x

 

[sellers]

Still, the only way to test properly is a multimeter or a test lamp!

Or finger, or tongue :coat

Jokes asside, if you look at the cost of a decent set of test lamps (35quid) and the fact that they save your life, its only a small price to pay. You pay more to fill your car up everyweek.

I'm sure many of us have had shocks before, through your own or someone elses stupidity, and the fact that we're still here is only because we're lucky! It can kill very easily.

 

[Risteard]

Phase testers have to be about the most dangerous "tool" available, and I agree that they should be banned.

I remember someone saying that for safe isolation he checked not only with one phase tester, but two in case the first one wasn't working. No mention of proving either of them on a known live source before and after, or of the concept that failure of the phase tester could route the circuit through him to earth.

It's amazing how many believe that the industry's safe isolation procedure is a waste of time and would get upset with employees for utilising it.

 

[sparks2911]

doesn't GS38 have some bearing on this too ?

 

[Badger]

http://us.fluke.com/usen/Products/Fluke+1AC-I.htm?catalog_name=FlukeUnitedStates&category=ELT(FlukeProducts)

http://us.fluke.com/usen/Products/Fluke++T5.htm?catalog_name=FlukeUnitedStates&Category=IND(FlukeProducts)

are mine but i bought mine about 2 years ago so desings have changed since mine where made, excellent kit

 

[Barx]

Ever touched a good earth (e.g. copper heating/gas pipe) while using a neon. You get a little tingle. Just thought I'd share that tit bit. Kind of proves that your part of the circuit.

 

[Apache]

Ever touched a good earth (e.g. copper heating/gas pipe) while using a neon. You get a little tingle. Just thought I'd share that tit bit. Kind of proves that your part of the circuit.

yes

 

[revjames]

not an approved method of testing!

 

[ProDave]

Beware when discussing "neon screwdrivers"

The old, traditional neon screwdrivers that contain just a neon and resistor can be useful for a quick check, e.g testing why a light won't turn on, to see if it's the switch for instance. Particularly handy in an old installation with no cpc on the lighting, so no N or E at switch, so hard to test with a voltmeter. So I DO use one on occasions, but I don't think that makes me a cowboy.

But then there are other types of neon screwdriver that claim to test any circuit from 12V upwards. They have some electronics inside and a battery, and more likely an LED rather than a neon. Those are useless. They are simply too sensitive to have any meaningful use on a 230V system and will light up even on dead circuits. Complete waste of time.

Of course as others have said, they should NEVER be relied upon to "test for dead" before working on a circuit.

 

[Andy™]

Beware when discussing "neon screwdrivers"The old, traditional neon screwdrivers that contain just a neon and resistor can be useful for a quick check, e.g testing why a light won't turn on, to see if it's the switch for instance. Particularly handy in an old installation with no cpc on the lighting, so no N or E at switch, so hard to test with a voltmeter. So I DO use one on occasions, but I don't think that makes me a cowboy.

many new testers (like the fluke T140/120/100/70) do not require use of your body to complete a circuit to tell you if something is live or not. just touch the probe onto something and itll tell you if its live or not