Dangerous Device - Neon Mains Testing Screwdriver
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- เผยแพร่เมื่อ 30 พ.ค. 2024
- How not to test for mains voltage, and why you should never use one of these neon screwdriver testing efforts for anything.
These devices are unreliable, can indicate power when there is none, and in certain circumstances not illuminate at all, even though 240V or more is present.
The neon indicator is difficult to see in bright light such as outside.
The entire safety of the device depends on a small resistor inside, which if failed will result in the full mains voltage appearing on the end cap where you place your finger.
This example has a large hole in the end cap, so that water, dirt and dust can easily enter and bridge across the resistor.
They are also useless as screwdrivers, since the blade is made from a very soft metal, the handle is thin plastic, and they easily break.
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Only just found this.
Firstly, I have around 50 years experience in Electronics and will never shy away from making any mains installation safe if I notice a problem.
One of those little Neon screwdrivers saved my life one day.
I was working high up a ladder, replacing a floodlight bulb.
I had removed the fuse feeding the outside lights. I climbed the ladder and when I touched the live connection, the Neon lit.!
I climbed back down the ladder to find some twerp had put the fuse back in.! After muttering how stupid he was, I removed the fuse and put it in my pocket.
Secondly, I also have an LED glow screwdriver.
I was investigating a bad connection in a display, I know the switch was off, but did not intend to touch anything as I did not trust the installer. My LED screwdriver glowed whilst I was investigating the shoddy wiring. After further investigation, it was confirmed that the previous stupid installer had, not only cut off all Earth wires, but had in fact, put the light switch on the Neutral.!
These Screwdrivers are in fact very useful, as in the last case, a probe test would not have shown that the system was still live.
Exactly, they are not there to be relied upon or as a safety measure but one more line of defence against something abnormal - As you'd be using a screwdriver anyway, it's worth the small price for one of these.
You should always always always test the circuit is isolated before working on it, removing the fuse doesnt necessarily mean it's isolated. Also if you're working in a place where other people have access to the DB/CU you should Ideally place a caution notice on the board to avoid someone turning it on while you're working on it.
That said as an indicator they are OK, but not to be trusted in either indicating a circuit is live OR dead.
if you was a real spark, you would know that a flood light, uses either a sodium lamp or a mercuary vapour lamp.are you talking about a tungsten halogen fitting, that also is a lamp. the word bulb, is a lazy american speak for a lamp.
@@rogerdavid3297 Been doing this near on 55 years, so I can say with certainty you are rude.
Oh and BTW its a Floodlight Bulb.
I'm very satisfied with neon testers. I can't think of an occasion where one has let me down.
The day it'll let you down - You'll NEVER know about. Well, apart from possibly a quick flash. However, your family will definately KNOW 😢
product advertising claims old are rubbish and buy ours 😅
If you spend some time in any emerging economy, these neon testers are ubiquitous. These screwdrivers are made by brands like Talaria that westerners have probably never heard of, but have stood the test of time and are the most reliable in my experience. It is the contactless ones that I find unreliable and finicky with frequent false-positives that I don't use them anymore. I've never had any complaints about the neon testers whatsoever!
If you have a fault on the neutral wire then the two probe dectector will fail to detect a live terminal ..... But the neon probe will.
@Chris Collins and what about country that doesn't have earth? (or they are actually protection wires connected to breakers, not real earth). Father sometimes was testing against wall.. surprise, some brick walls are good enough to detect phase. By the way, same 240V here too, a phase and a zero though.
3:11 clearly lying for his own purpose, you can see the orange light come on then he moves the screwdriver tip to a point where it doesn't make contact
Stupid virgin
If you assume the worst, you can find L and N swapped (or worse, having the same colour!) and earth at live potential. This screwdriver will tell you if it's safe to touch a particular conductor.
With the voltage tester, you first have to know which cable is which (seems easy, if you assume that the electrician that installed the thing was sane and used the correct colours), you assume to have an earth available that you know it's connected, and you assume earth is not at live potential.
A lot of things can go wrong. Touch the wire with the screwdriver, if the light turns on, don't touch the cable, if the light stays off, well there is the change that there is no voltage, but better not touch anyway. The screwdriver can be used not only on electrical wires, but on cables, metal equipment, and so on. How do you test a machine to know that the chassis is not live (that is not earth or the earth is not working)?
Or simply, these screwdriver are a fast way to know if something is properly earthed. Try to touch with the screwdriver for example a PC that is not connected to an earth, the light of the screwdriver will turn on (even if it's not dangerous because the current is so low that you can barely feel it). It's also useful to test for line voltage on things where you don't expect voltage, telephone and network cables, TV coaxial cables, security alarm, etc. Better do that before touching them.
@@RaiderOfTheLost except he isn’t lying and it doesn’t illuminate.
Yes you are right. But this prick is using a 500v tester on 240 v. No wonder he can hatdly see the light.
I hope he does not claim to be an electrician.
As a retired electrical engineer I am surprised that you did not mention the verification stage following a circuit test. If the testing device shows a 'live' indication then fair enough it is live but a null indication, i.e. 'dead', should be followed by a test of the testing device to verify that it is working. I used a 'proving stick' when servicing 11 kV switch-gear and it was provided with a hand-operated magneto to verify that the stick was working after a test.
You only know the power is off once you've connected L and N (or L1,L2,L3,N&E ) in a connector block. ;)
Quite correct. This is also clearly stated in the Drummond test lamp instructions. "Test on a known live following a dead test".
My dad had one of those when I was a kid. I remember two things about it. 1 I was very disappointed by the barely visible glow when I stuck it in the mains and 2 it was a really good screwdriver - just the right size tip and a long thin insulated neck.
Looks similar to one my dad had - nothing left of the screwdriver tip - he'd ground it to a point so it could be used to pierce insulation !
never have i had a neon fail to light, i must be a god. the god of neon.
Neon screwdriver is best tool ever made. It is essential to have one of these. All other expensive stuff is just optional.
My college electrician made a very good point about these (or equivalent non-contact tools) -- under previous employer he was told to always check with the neon as well, as these would reliably glow in the presence of entirely floating supply (e.g. lost PEN on older supply converted to TN-C-S...).
The biggest shock I ever got was a floating neutral. Went across my chest - all the mains switches were off, all earth leakages off. ZAP! Very unexpected. I wish I had had one of these screwdrivers for sure!
@@Mrcloc I once tested an earth lead and it lit. Puzzled me for a while then I figured it out - it was me that was live - somehow - never actually got to the source - perhaps just atmospherics !
Wrong. You don't use a two terminal device to check mains voltage is off unless you know the circuit has not problems. Neutral may be disconnected and live connected and that device would not give and indication. There is no perfect solution but if you are going to check live wires around the house, use one of those pen things. Yes they may fail, but the two terminal device can also fail.
Both devices that you said are bad give out false positives but that is actually safer than a false negative from a two terminal device due to a broken neutral.
+maxsnts That's a good point that I never picked up on, the two terminal device he used (not the multimeter) would that work if the other terminal was grounded against a radiator perhaps? That might be it's true purpose, that you ground the other end and not place it against the unproven neutral line.
+maxsnts I have seen broken neutral my self some times not easy to find with a 2 point tester
+Rob Fraser They may work if grounded, but around the house when checking for normal mains, i want to see if "I would be closing the circuit" to ground and get shocked. Its the same reason i don't use a multimeter for these checks. I don't care if neutral or ground are good, all i need to see is if i would be closing the circuit to ground.
I agree with you. I've used one for over 55 years and always found the live. A lick of the finger to lower the resistance helps too. He's scaremongering.
Voltage is the SI unit for the electrical potential difference (PD) between two points. So if one side is supply voltage (230V) and the other is at 0V then the Potential Difference is 230V. If both are at the same Voltage then the PD is 0V. So its not the equipment but the understanding of how to use it, learn how a multimeter works. If it is a broken neutral you are worried about then then check on earth conductor, if no earth conductor the use a wander lead to a known good neutral or bonded point. You only require a reference point to ground to prove dead. fully isolate then check continuity of circuit.
A phase tester in the form of a screwdriver can shine only when we believe it is also the phase.
The same is true for the non-contact voltage tester . If you hold it on neutral , it's not lit.
I think you've reversed the phase and the neutral conductor in the video. Therefore, the phase tester and the Non-contact voltage tester has not shone on the brown wire.
A digital multimeter also measures something if there be only one test probe to the phase. Since you started with a multimeter at Brown and the meter showed nothing , you were at Brown clearly neutral .
Conclusion: The phase tester works all the time - just because you have kept him on the wrong wire , he has not lit up .
I have voltage tester in all forms. No one has ever left me in the sting, or given a lesson ...
In electrical engineering, you learn that you should test each voltage tester before use for proper operation .
to djblackarrow - you are correct; he switched the live and neutral. If what he claims is true, he should have shown a single sequence leaving the two-pole tester in place (and lit) and then touch the tester first on one and then on the other wire. The man is a cheat.
While maybe a bit more unsafe, I find the single-ended measurement devices very useful when checking which wire is live and which one is neutral. Very important when installing switches, dimmers, etc... when you have no direct ground available. (otherwise, you can measure the reference to the ground)
Whenever you're comparing a working case vs. a nonworking case, you need to tell us the difference. Just saying mysteriously "in this case it works, in this case it doesn't" with no apparent difference in the two setups, is idiocy.
Agreed. This chaps content is usually strong, but this his not his best.
It's really simple. He just swapped live/neutral wires *). A common thing in older buildings. Never trust blue/brown colors. Always test ALL cables. Why didn't he do it? When he presented "and here it doesn't work" he NEVER tried touching the OTHER wire. So that's pretty damn useless test and total B.S. Also, anyone who played with "plasma bulb" knows that it will light up neon or fluorescent lights. Whee. Magic. Look how bad is that neon bulb. For all's sake, all it proves is that the neon bulb WORKS! Hey, it just detected you've got a goddam TESLA COIL there! I will be REALLY HAPPY if my old trusty 1980 neon lamp screwdriver starts lighting up when I touch it to the wall, "just" because my neighbour connected the wall-wires to some several-tens-of-kilovolts!
Edit:
*) others also pointed out an isolation-transformer to remove earth reference. Yep, that's also possible. I still think he just swapped the wires tough.
Would agree that you had a bad neutral, the two pole tester could equally fool you into thinking a terminal was not live. The powered mains detector subject to proximity issues. TBH phase testers (that pass a tiny current through the body and failure modes most likely go open circuit. I won't be throwing my phase testers away at all and they are the only item discussed that actually tests the users path to ground from a live terminal.
3:11 clearly lying for his own purpose, you can see the orange light come on then he moves the screwdriver tip to a point where it doesn't make contact
Stupid virgin
@@quetzalcoatl-pl what if he just took his feet off the floor? Less so with the pen, which is amplified, but it seems like the neon would require a somewhat stiff connection to earth to function, if you were sufficiently isolated, would it still work?
As an electrician I would say they're better than nothing if you're doing a bit of diy and have a reasonably good idea what you're doing. I personally use a Megger 2 lead voltage tester and voltstick for easily identifying cables. I've probably binned about 6 of these because they often come free with a set of VDE screwdrivers, I do still have one with the insulation stripped off that I use to stab through platerboard to find rafters though
Many people on DIY forums diss the neon test screwdriver. And they say get a multimeter instead. What do you think? 2 probes better than 1? LOL I think it simply doubles the risk
I would say that nothing is better than test kit that gives a bogus result and makes you think that live wires are not live. If you have nothing then you are more likely to find another, better way to test.
Am working as an industrial electrician and have lost count of the times that I have wasted hours trying to find where the voltage indicated by my tester was coming from only to find that there was a plasma ball hidden from my view!! Damn plasma balls are downright misleading and should be a lot less common than they are.
Jon Smith 😂
Hi
Lol, I know this is a joke but, I genuinely had this problem before 😂. I was rewiring my room’s electrical sockets and I was using one of these neon testers to detect if I tripped the correct breaker and it was detecting my plasma globe which was on the table nearby but, this actually helped me because I obviously did not trip the correct breaker because the plasma globe was on.
You had to demonstrate a yellow one, didn't you? It is far easier to see the glow with a see-through one. I've used such screwdrivers for years now and the only problem I've had was how weak they are. If you use them as ordinary screwdrivers they break easily.
When you said "absolutely nothing" it actually glowed very very dimly. I tested mine while wearing thick rubber boots and indeed it glows very dimly but I could see it because the plastic was see-through.
The reasons why I prefer neon screwdrivers over your two-probe tester are as follows:
-neon screwdrivers are much cheaper
-they are small enough to fit in my pocket
-they show which wire is live, while the two-probe tester only shows that one point is live but you don't know which one
-if for some reason both the live and "neutral" wires are live the two-probe tester won't light up but the neon screwdriver will.
The other single-probe tester you show is certainly safer but if the battery runs out you are in trouble.
I will continue to use neon screwdrivers like all other electricians in my country.
One concern about the two-probe recommended tester is that it assumes a viable neutral. If the hot is connected to mains and the neutral is open, the two-probe tester will indicate a cold circuit, even though full mains voltage will be present and could kill you dead as a door nail (or any other kind of nail). The forbidden pen, or the little squawker, will tell you there is power present even with an open neutral. The forbidden pen will go further and tell you which of the nest of wires is tripping the squawker.
The false positive from a plasma lamp made sense, but frankly, I don't often see these hiding behind junction boxes. I am curious how you got the failure of no light with voltage present. I am supposing you wore very, very good insulated shoes, maybe also standing on a rubber mat? Or instead of true mains power, you pulled your test voltage off a transformer or generator without a bonded neutral?
One great advantage of the neon testers is that they require only one point to test. There are some cases when you have to use them:
if you don't know which wire is the line or the null (same color of wires and no known ground is available) or if you are not sure if the null or ground is damaged you have to test the line with the tester before starting the repair
Used that type of tester my whole life,and im still alive.
That is a very bad argument. Electric accidents are rare but they can happen.
@@okaro6595 front tyres on my car have 0.5mm tread left and I'm still alive!
Buy a sodding multimeter cme
Me too. And I can't imagine how you would get hurt by this unless you were maybe testing over 600 volts?
The point of this tool is that it identifies a hot wire -or which side of a broken neutral carries a load.
It's quicker than a multi-meter when you're testing 40 breakers in a panel too. More reliable than a non-contact tester in a group of wires.
I love this tool and they last forever -I lose them WAY before they die.
Me too! :)
@Fred Bloggs I use my non contact for things like THHN in a junction box when there's a bunch coming from Greenfield or EMT, or turning off a CB at a distance when it makes no sense to use my circuit tracer.
I'm an electrician with 30+ years of experience. Sometimes (rarely) I work contacts close together so a touch tester is great when my non contact would be useless.
The problem with ANY 2-contact tool is needing 2 hands.
Actually, very factual comments and yes, lethal for the untrained persons. However, as a maintenance electrician in the 1960`s - 1980`s, I found these little tools invaluable when fault finding. i.e. when working on complex production machine control panels where we were looking for voltages at certain time. These were often only a little blips as a component passed through a gate etc. or working on automatic electro Plating plants, just to name a few.... Remembering of course we are talking about complex relay and contactor switching controls. Semi conductors only started showing there faces early 60`s.
Final point and has already been stated, NEVER reply on just a neon tester. Always make a point of using the correct tools to make sure ciriuts are indeed safely isolated if about to undergao work.
The Nean Screwdriver tool, used within it`s correct paramitors of it`s design, saftey and usage, were and still are wonderful, and I still use one at the age of 80. Yes, I`m still living and never been killed by a lone neon tester ............YET!
Steve T
My dad was using it for years, and now he's still fine...
99.9% of the time nothing bad happens. I would rather use the equipment that has been designed and tested to protect me from a lethal shock than trust somthing that hasn't been tested to the same standard hoping that the 0.1% of the time never happens to me.
You can only die once; I don't wear a climbing harness, use ropes etc to stop me falling off a cliff, i use them to stop me hitting the ground!
One of the problem is, it is also a screw driver, when that kind plastic get old, it will crack and shatter. Anyone also have same experience that the entire screw driver shatter in your hand while you work on a screw with 220v live?
@@luderickwong - Yeah if there was a crack, exposure, or even moisture > ZAP > LEATHAL SHOCK!!!
@@luderickwong Any type of screwdriver can be damaged. What's your point?
@@luderickwong In Finland at the some point those could not have the screwdriver. That made them completely useless. Most people use those only as screwdrivers.
A non-contact voltage tester is better.
Dear Sir!I am an electrician and never had any problem with such devices.Yes there are other types of phase testers too.Trained,learned experienced maintenance workers,installateurs never died using these devices.Non craftmans, amateurs, may, but never heard of any.If one wants to know there's no voltage then double check with LED tester spec device,multimeter.Contactless beeping light testers can be unreliable too in some situations
Károly Varga I bet you don't even actually have a job
I would have been useful to state the conditions that stopped the screwdriver working ( swapped live/neutral or removed the bulb?).
Presumably he was wearing rubber shoes or something
+Jon Laws Presumably, he swapped live and neutral.
It's not unknown for a wall socket to have live and neutral swapped for decades without anyone noticing. That's why you, when proving dead, you have to check the voltage difference rather than just the voltage.
I think due to the slightly higher voltage the connections were from an isolating transformer
If you look closely, the tool is bent when it "doesn't work" -I think he intentionally broke it to try to make his point.
As an electrician with 30 years experience, I use this tool all the time without fear.
By the way, you don't need to be grounded to use it, so having rubber shoes doesn't make any difference.
If you do ground yourself while using it, you simply get a brighter light. I often do this to see if the neutral or ground are not connected. In other words, if the light doesn't get brighter, I trust that the neutral or the ground (whichever I'm touching) isn't connected. Even if it does get brighter, I will still take a voltage reading for precision.
Because testing is so fast, this tool is fantastic when diagnosing multiple locations quickly.
Also worth noting: if you touch it to a neutral it won't light up -but then if you touch a hot, it will light. Congrats: you just found a receptacle with reversed polarity. So I might stick it in the hot end side of receptacle, not get a reading, ground myself on the box casing, still not get a reading, stick it in the "neutral", get a dim light, touch the case ground, the light brightens, and that means there's reverse polarity because the neutral should never read as being "hot". I'll still take apart the receptacle to double check, but this is faster than using two probes on a VOM.
@@SwingboyPA "If you do ground yourself while using it, you simply get a brighter light." Yeah - that's your poxy 110V ;)
Here in the UK we get a tingle too!
I want that amazing cardboard power source!
Hide a plasma ball or van de graaff generator under a sheet of cardboard and Roberts your father's brother
Tesla coil
What if the lamp goes in the two point testing device? That's why I always use the tip of my tongue - readings are much more accurate
The neon tester works without a ground connection because your body is capacitively coupled to ground.
I still have one of these purchased some 40 years ago, still works today. As you stated, only use to confirm mains present. NOT to confirm mains off. Mine has a standard type 1.5m ohm resister fitted. The older ones are somewhat better than the made in China crap. Needless to say mine is UK made! Made in the days when UK did make stuff, not just add a brand name to China rubbish.
Michael Beeny Yea, Its all fun and games until that resistor shorts out or an internal short occurs. That jumps the resistor... That little resistor is all that is between you and a injury or death.
TG Lasers at all those amp's that a neon lam uses????
Michael Beeny These testers are a dangerous. A decent multimeter can be had for not a lot of money now. I would not risk getting a belt from one of these so called neon testers. Especially a 40 year old one made when our engineering prowess was represented by the products of British Leyland.
Properly said Morten Kristoffersen
Michael Beeny I doesn't matter whether it's China made or not. It's just what you get for what you paid for. Needless to say all the Apple products are made in China, and also China has it's own very successful manned space program. I'm sick of people always saying "Chinese made crap", they should rather blame the doggy importer and their shallow pocket.
By the way, I have a Chinese made nicely built neon tester. Actually it has the similar structure as you described above, i.e. STD resistor with neon in a fuse like tube. I have no reason to believe it is dangerous or will fail any time soon. Of course it is More Expensive than the one in the video.
Your two pole tester tests for voltage between two poles and will give dangerous non-reading if say neutral is disconnected. The neon device tests whether a single terminal is likely to hurt and provided you check its functionality in current lighting is pretty safe
exactly!
Well yes but no if the carbon resistor fails and you then put your finger on the cap you will receive the full 230 volts hence why they are awful
As they say the proof of the pudding is in the eating, and these neon testing screwdrivers have been around since the 1950's decade, and so it would be interesting to look at past documented lethal accidents corresponding to their use. Surely the following institutions such as the IET, Hse, or British Standards will have records of electrocutions in their archives.
I do not dispute the opinion of John Ward, and I would be hesitant to use one on these screwdrivers from the unreliability point of view, however it would be nice to have some sort of proven history to back up John's hypothesis. Finally surely after all the years that have elapsed since these screwdrivers were introduced they would have been banned when the first fatal accident occurred. Incidentally I have noticed only this week that the 'Pound land' shops have a job lot of these screwdrivers on sale 'currently' (no pun intended).
As any spark that is worth is salt will tell you that the sure way to check for the live phase of a UK mains circuit is with a multimeter switched to AC volts with the negative lead clipped to a reliable earthing point, and the positive lead used to identify the phase.
Thank you MIET.
Unlikely to get any real data, as the instances of fatality will be very low, and the vast majority of electric shocks received from these and other items will go unreported.
You are quite correct in that the instances of fatality will be very low, and the vast majority of shocks will go unreported, however 'one fatality is one too many', and one would have thought that in our safety aware age that there would be some recorded mishaps out there.
Furthermore with the big hand of the EU overseeing everything one would have thought that these screwdrivers would have come under the spotlight for vigorous safety testing, however how many times have we seen other instances in the corporate manufacturing world where things that have a history of being hazardous are ignored?
One example is the flammable Halloween outfits, that despite being potential killers were still being sold, and may still be as I write this. I recall that Tv's Claudia Winkleman's daughter had such an accident, and campaigned to have the clothing banned, however at last years Halloween, surprise, surprise, the same lethal stuff was being sold yet again.
You are dumb dont get pissed but in that thing is a diode so you dont get shock
The reality is that any testing device can become damaged and give unreliable readings, hence why you always check on a known live circuit to verify it is working, and if high voltage, double check with a second meter. No authority is going to issue blame to the testing device itself, it's the operators responsibility to verify it is working properly.
Get a klein NCVT-2 it has built in self-test circuit, even then double check.
And how is diode supposed to help there?
If they were that dangerous shops wouldn't so readily sell it and say "hey stick this against live Mains" people would be dropping dead, stores would be sued and the product would be taken from shelves
My only takeaway from this is that you prefer cheap editing tricks to information.
Both single ended sensing devices detect voltages above earth, one requires a low impedance path to ground reference (screwdriver,neon bulb, metal cap to finger) and one works at very high impedance (solid state voltage tester, jfet, hand touching outside of plastic housing).
The two terminal probing not only is huge, but only tells you a difference is there, not which leg is above ground potential.
Exactly
How exactly is that "cheap editing tricks"?
If you can't understand this, my god.....
We used these in the late 70's when you could trust your tools.. Before the CE label..They were great for detecting anything over 90 volts AC completing the circuit. EHV just by holding them close to a flyback transformer, TUBE/VALVE without grounding yourself or touching anything that was grounded. The good old days, pre CE days. I encourage you to keep posting your videos, fact is greater than the fiction that your latest posters swear by.. Try using this neon driver on a EHV flyback while in bare feet on a concrete floor, my buddy still has nightmares. I must admit it has served me well.Used with knowledge it was indispensable, without knowledge it was dangerous . It is now obsolete even though I have several of them I am an early 70's TV technician, 425 and 625 Colour/Black and White capable dude .Still going strong with the latest technology. 2015...... Soon for the dump...
Aahahahahahaha. Bring back rationing! Things were better in the old days. And there are billions of electricians dying in the EU because of the CE label. I assume you've got some good excuses for the HGV driver shortages now, or why we need to renegotiate Johnson's 'oven ready deal'. It's always a foreigner's fault eh? Get a grip man.
hallo Mr. Ward,
Where can i buy this safety Volttester. How he measurement with a bulb?
Thanks for the suggestions you have discussed here.
I've got a Schneider Electric socket tester. It also requires you to put your finger on to a metal contact in order to test the socket. Is that unsafe ?
The screwdriver demonstrates if there is a potentiale between a wire and ground i.e. you. And that is exactly what I need when I test an unknown mains. As others suggest I test the screwdriver against a known source before use - and so I also know how much light the particular screwdriver is displaying.
I am wondering why John Ward finds it a failure that the screwdrivers does not to light up when he obviously is touching the insulation.
The question that should be asked is; how many lives has the neon screwdriver saved? Especially amongst people who have limited electrical experience. As most people will have this tool, but not a two pole device.
I was always taught to not use the led test screwdriver. One day working with a very 'switched on' Polish guy, always used one...he critised me for using my Fluke voltage detectors and I just said, I dont think these screw drivers are very safe - in a nut shell, checking an em/light on a night shift, he threw his test screwdriver so far on the floor and walked off. Me being slightly confused? his reply to my 'you alright' question - "I got a f-ing shock" - he still continued to use that same tool (out of pride?) anyways!! they are not 100% safe!!!!!
as a retired sparky i hate these stupid neon testers .i use the voltstick that works like an oral b toothbrush charger no chance of a shock i have seen DIY sparks get shocked from the neon devices they should be banned
You have to be really careful with those 2-point testers because if the "zero" line is broken... tester shows there is no power there. That will deceive you into thinking that you can touch wires with your hands. And then you will be killed by the "positive" wire. I like your videos by this one is a fail. You have to use these single pole probes in order to be sure! Just buy a good one and you'll be OK.
This is why you should first test with the two prong prove that the power is on. If you know that the power is on (Ie with a volt sick) and your two prong prove doesn't register voltage then either it's broken or you don't have a circuit. Then test between live and earth to see if the neutral is connected and neutral and earth to see if it's wired wrong.
After confirming that the two prong works and you have power then turn it off and use it to confirm the lack of volts. Now finally use a proving unit to confirm that the probe still functions and didn't break between the first two tests.
Yes it's long winded but it's the only way to be sure you're safe.
alihaggis78 You are most probably right. Thank you for this explanation. I have never heard of a single person killed because of (or by a) neon screwdriver though. I think that alcohol is something that kills electricians more often ;) But indeed... this thing may be dangerous.
alihaggis78 What you're describing is a diagnostic procedure. That's all not needed if all you want to do is turn the power off, confirm it's off, change the wall socket or whatnot and turn it back on, confirm it's on. Then all you need is the single point probe, test all the wires, confirm no voltage on any and you're good.
You're making a different point than the OP, he just said 2 point tester might not show a fault you're unaware of and you'll assume it's safe and consequently get hurt, so better to use a single point tester. The single point tester will not help you diagnose the problem (that you don't know about, remember, so you're not looking for it), but you WILL be safe if you test all the wires with it.
If you know there's a problem then yeah, 2 point probes are needed to get more details on the issue, but that was not what the OP was saying, different situation.
he switched the live and neutral in the camera cut, so they wouldnt detect on the live wire, also spaced it well away from the real live wire so the non contact didnt pick it up by mistake
well i'm glad i watched your video, i have bought many of these over the years and used them to test and change light fittings etc after switching off at main circuit board, not once did it say on the packaging that i need to be in contact with the metal top. therefore all this time i have thought i was ensuring there was no current running but infact me holding the device like a pen was useless and i'm probably very lucky not to have lived in a property with faulty wiring or circuit board.
I can see the headline now: Idiot electrocutes himself opening a light fitting.
Wow glad you had no mishaps, so you can't be the only person who doesn't know how to use these properly. I always test these screwdrivers a few times (before using it to confirm if a wire is dead) at a live plug socket to make sure the light inside is still working. I can't believe you never did this and so never saw it light up, atleast you know now. TH-cam may have saved your life! After watching this I'll be using my multimeter not one of these things.
Buntzums wow, fuck you.
***** I always pull out the multimeter and test it accordingly on a known circuit before commencing work. Unlike 120/240... industrial 450VAC/600VAC/800VDC circuits are unforgiving.
I do appreciate your videos. Interesting one on the neon tester screwdriver. I agree it could be made intrinsically safe on paper - by the addition of another series resistor so there would have to be two failures before a significant shock hazard but it's still very unlikely the resistive element should fail short circuit given the lack of stress time to the component. The more significant hazard would be water ingress but then again the other testers you show would also be prone to such an IPxx exeption. You also didn't mention the hazard of through conduction from lead tip to loose tip (if inadvertently touched) with your test lamp or an open circuit neutral making two lead testers problematic.
I own a Steadfast neon tester which is sealed with a tight screw on machined aluminium endcap and therefore waterproof.
The advantage of the neon tester is its simplicity and using your body as a current limited capacitive earth so only needing one touch metal "connection" to the live terminal. It safely copes with a missing neutral fault too unlike your two lead testers and you can dab it around to spot reversed polarity and even a live CPC! It's less prone to stray electric field pick up like your "Volt stick" too. You know if the neon lights it's "live" with voltage but as you correctly point out with a high PV field from your Tesla lamp, it lights but does not indicate current capacity - but then again a false positive in that case is not a hazard.
The safe way to use the neon is to confirm it lights on the item(s) in question then isolate the supply and repeat the exact same test to confirm it does NOT now light up. That way you cover all the variables of lighting, position etc. I'd argue that a good quality neon tester's simplicity and ease of use, coupled with knowledge of its capabilities make it safer for live indication than your other testers. Imagine if your CPC and neutral were cut - how would your two wire testers cope with that? 😮
I'm glad you see it my way.
Dad's garage was 'off' - nothing would work except the neon tester. Yep broken neutral - but it had him puzzled ;)
Considering everyone gets them for free with new insulated screwdriver sets, I don't see why you wouldn't keep one or ten in your toolbags
John did say "sometimes it doesn't work at all, as I will now demonstrate. Here we have the same setup with the mains on this side (pointing to blue wire)".
So that would indicate brown would be the neutral in this instance...
Those fancy meters break too. Happened to me. I was being very careful, working in a wet basement on 220 volt controller box for well pump. Brand new multi meter showed no power. Found out later the selector switch broke off inside allowing some readings. (Cheap junk from China.) I didn't bring my good one for fear it would get ruined. Anyway, I had the screw driver and used it to verify power. Remember, in bad situation or high risk, verify for added safety. Those screw drivers were made for people in the third world that cannot afford the fancy stuff. They also work if your body is insulated, working on the EMFs from the current. Just be careful. Try to avoid using those cheap meters too.
Yes but if the neutral was disconnected on his test rig, the lamp wouldn't light even though the live terminal was live. A neon tester in that case would be able to show the live terminal was live.
Jusb1066 said switched, not disconnected. If it's simply disconnected, then the lamp tester wouldn't light up either, but if the hot and neutral lines were reversed, (where blue is now hot and brown is neutral), then touching the brown wouldn't light up the neon tester. Going across both lines with the lamp would, since it operates off the differential between the two terminals.
It would have been telling if the terminal with the blue wire was touched with the neon tester, but unfortunately that wasn't done.
In the video, we see that the resistor is place between the probe end and the neon lamp. Does it matter if the resistor is placed between the neon lamp and the top cap?
I used to use one against the glass of acline output valve in TVs to check the presence of RF. Invaluable for that.
hi john Can I ask u a question.
I am boarding my loft and I have come across some older conduit with wires in where some are taped up at the end when exiting the conduit, and 2 seem to be going elsewhere although I cant find the end yet as they are under loads of insulation. Now the house has been rewired and there are quite a few newer grey coaxes in the loft aswell but I am not 100% that the wires in the older 1950's looking conduit are still live and connected to my new fusebox in someway . So what would do you think and also recommend the best testers and yes I have 2 of those plastic screwdrivers.
Thanks P
+staypress Ask / hire / pay a trained and certified electrician, for goodness' sake!
What is that proper device you are using?
Agree with what is being said. I was *shocked* at how bad the light was inside on of these things so it went in the bin and replaced by a non-contact voltage detector with a big flashing LED and buzzer. Far safer and clearer IMO.
IMO, since there already exist far more reliable voltage detection tools for little money, particularly detection tools that can sense current without having to probe leads, there's not even an excuse for these neon testers to be used anymore.
reliably.... never found one that was no-touch and was reliable enough to distinguish a 'dead' phase in a 3-phase system, neon-type works almost all the times instead.
But the neon tester would not be used anymore?
Novice question - if you disconnect the neutral wire in you demonstration (blue wire, and disconnect from the remote end - not the connector you are testing) I'm assuming that your two pole device would show no voltage ? And in that setup only a single pole device would show voltage on the brown wire ?
netrixuser Yes, a basic two pole testing device (such as the black one with a lamp in it) requires both probes to be connected. However most of the newer voltage indicators also include the single pole detection as well.
+ĺll jji
Very useful devices! Always worked for me (for years). The light output can be low, but you learn to look for it. Always confirm that it's functioning by testing it first on a *known* live contact
The comments scare me. I always knew they were supposed to be able to test for voltage but why would you ever think it would be a good enough test on its own? I wouldn't mind but they actually look and feel like cheap shitty screwdrivers, and you're trusting it to tell you if something is live...
Quite. Even if you want/need to use a single pole tester, there are much safer ones around, including ones that only cost a little over a pound, delivered.
the point of the tester is to check if there is any voltage leaking the difference is the neon bulb tester is low impedance and the fancy one is high impedance THEY WILL NOT WORK THE SAME IN SOME CONDITIONS
Personally I use my DVM to check if power is there when the circuit is energised. I then switch it off and check that now the DVM shows no volts
The neon is a useful tool and could be used before and after as confirmation. The carbon resistor will be a type that fails open, also the neon will be a low wattage one that vapourises before it can pas lethal amounts of energy. Thinking about what you are doing around lethal voltages is a good habit, I applaud both this video and the comments.
If they are technically sound (no structural failure, not damp, not tampered with, etc.) it's all safe and fine.
If you use a multimeter and measure what comes out of the probe when you insert it in the socket you get around 58 volts and 5 microamps, that can't kill you.
You can use Ohm's law as well, your resistor element gave you 1.5M Ohms A=V/R ~ 160 microamps, nonlethal....
What did you do at 3:12 and 7:16? Switch live and neutral around? In this case, at least one of the terminals will still show a reading. However, if your neutral is broken and your live is still connected, the two terminal prove won't show a reading. I know that's not the full procedure, but switching live and neutral around is not proof that the stick device is completely useless. Rather, one should be educated on how to use each of one's tools and what their limitations are.
I'm not sure I see the point of the two terminal probe. If I had that simple case of two exposed metal terminals then I'd use a multimeter between them. OTOH a common scenario for a power tester is if (say) I come across a red wire under a floorboard and I want to know if it's live or not. No terminals available. I don't have a tool for measuring electrical field, so the light up pen is about the only thing you can use AFAIK. I find that they're more reliable if you rove them around - they seem to be more sensitive to a moving field.
I swapped a single socket for a twin at a friend's house. Easy job but testing my work resulted in me checking out the whole ring main - under the downstairs floorboards. I found single-insulated cores for the lights - damp, cracked insulation - lit a neon tester no bother - so you can use them for insulation resistance tests too ;)
I had a socket, which has 2 live. Between those 2 terminal there vere 0 volts. But between the floor of the building, and any termial.. Deadly. Those crappy screwdrivers showed the turth.
Or maybe a broken neutral. This couldn't be detected with the "lamp".
I THINK it's more likely to fall off a neutral than there be more than "normal voltage".
Use them both! Or maybe the battery powered one, but anyway first test it with a known working live.
Are you being serious? The reason there was 0V between the two terminals was because there was no potential difference between the two terminals i.e. they were at the same voltage.
The neutral is the return path for the current and under normal circumstances would be at 0V after the voltage has been dropped across the loads on the circuit.
I don't think you should carryout any electrical work if you don't understand the basic principles.
That is the point! There is no potential difference between the two wires, but between either wire and earth it is 240! (It wasn't me, my grandfather made it). So any 2 probe measuring this is useless. Bonus, the socket has earthing connection, which is NOT connected to anything. The socket has a switch which is somehow works, turns one live into neutral, so you can switch on, and swich very on the connector. If both is live, the connected device not working.
And what I wanted to say: If I would test it with a 2 probe thing, it would say that it is safe. But isn't. But a crappy screwdriver says that it is very dangerous.
But yeah, switch off the main switch, it safer.
I would get some one qualified to check and repair and test. If the socket is used to supply items that require a protective conductor e.g. class one electrical items then its dangerous if a fault occurs.
Also sounds like you have a big problem with polarity i.e. line and neutrals being mixed, not good and dangerous dependant on type of circuit breakers single / double pole etc!
Also learn how the test equipment works and how to interpretate the results.
Sorry John, but I don't feel this is a responsible video. In many situations, and used in the correct way, this is a very useful tool. And given that a multimeter, or any other test device that relies on a path to neutral, can also give a false reading, the argument is not sound. Your content is usually strong, but I think you should reconsider this video remembering that this content is watched by all sorts of different people with differing skill levels. And before the sparks say people should not be touching electrics, changing a power outlet is permitted, and a neon indicator is probably the only test device some people have.
Hi John - nice video, and sound advice. But when you say these devices are no use for anything - I have found these screwdrivers make a great cheap HV indicator, from a terminal to free space (not using the human body in the circuit) when the voltage and corona/spark/arc current are enough to light the neon. Might be useful for Tesla coil tuning (but no touching, hands at least 5 feet away please). My video shows a neon screwdriver on fire after being subjected to more than 250,000 volts. But it won't be going anywhere near my general purpose tool box after that experience.
The video explains very well. The voltage test pen is still necessary. I bought a renhotecic brand test pen not long ago. The test is very convenient, accurate and safe. Family must.
It won't work if you are touching the pole that is grounded. Is it possible the blue is not neutral?
The neon is the high resistance that will prevent you from getting a shock.
I remember when I was in my apprenticeship in a power station they called the screw driver "lying stick". You always use a voltage tester with two test probes! A multimeter can be dangerous too if you choose the wrong range (eg. amp. range for voltage) this is the reason why professional electrician always work with special designed voltage and and continuity testers. This devices are save to use. For a house installation or trouble shooting you often only need a quality voltage and continuity tester.
A voltage tester can only answer the question voltage there yes or no, same with a continuity tester, continuity yes or no. If you like to know how much voltage or how much resistance you use a multimeter.
'Lying Stick' - excellent name.
TheBuggy73 Or in the case of an electrician in many cases a multifunction tester.
Before using any tester you should use it on a known-live circuit to test the tester itself. Yes the pen devices could fail but then so could your two-pole tester - what if the bulb blew? There's also a problem with using a tester between the live and neutral in that, if there's a break in the neutral wire, or it's otherwise not connected, the test would show no voltage yet the live wire would still be 'hot'.
No one has asked a very important question, if and that’s a big if the neon screwdriver is dangerous ? Would JW a very experienced electrician put his finger on the end of that neon screwdriver knowing he could potentially kill him self? No of course he wouldn’t, secondly he did not touch the live terminal every time, they are not dangerous if they were they would have been taken off the market year ago. There are two types available the 6in rated at 500V and an 8in rated at a 1000V both have been available since the 50s and are perfectly safe as long as they are used correctly. But they should not be relied on as with the non contact voltage stick.
I'd always wondered how they work. Now knowing that your body is used as a route to ground while sticking them into the mains electricity is certainly food for thought about whether to use them or not!
They are fine, this is hysterical nonsense. On domestic circuits the resister would fail open meaning no shock. He is being dishonest and designed the tests to fail due to his obvious bias.
That "approved" two pole test lamp he is using could get you killed if the neutral was not connected, however the screwdriver would still detect the live wire and save your life. Of course he doesn't mention that, now ask yourself why he doesn't.
As with everything, know the limitations of the testing kit. There are gazillions of these screwdrivers in use, they would have been banned decades ago.
Use them in your right hand - slightly harder for the jolt to pass through your heart on the way down :)
If you dont mind explain the card board lighting the test light.
I have always used that when I need to change a switch or lighting fixture
I have one of these testing screwdrivers but mine has a wire coming out of the end with a crocodile clip on the end. Is this clip for clipping it onto something to earth it? I don't know.
Probably for testing 12V circuits such as those found in vehicles.
Hi, I watch your video closely. I am using this screwdriver for a couple of years now without any problems. Of course this screwdriver works only on the live. I believe you change the live and
neutral to “eye blind” the viewers. See the clip on 3.55 minutes and it shows the tester is showing a positive reading
though the black wire was on the live and the red was on neutral. Please explain… I try to figure out the cardboard… Why not remove
the cardboard to proof nothing was under the cardboard?
How do you use a Fluke 117 RMS meter and not the Fluke Volt Alert?
Could you please explain as well what happens if you connect one pole of the two pole detector to the live and accidentally touch yourself with the other end?
You may get a mild shock, don't ever do this.
been using neon screwdrivers for years touch earthed metal work with your over hand and they really glow
Mine has a plastic cap at the end and no metal. Wonder how that works? Or does it...
thanks john. gas engineer ere and i use there for quick diagnostics for live wires for heating controls. is there a safe alternative screwdriver that does the same thing? thanks
www.socketandsee.co.uk/socket-and-see-epf-pro-hazardous-voltage-and-phase-finder.html
I use a multimeter to test electrical for being live, but I also never trust any equipment to tell me if something is live. Tools can fail or be used wrong. I never touch potentially hot mains without putting the wire to a known ground or neutral first. The wire is rated to deliver 15A, and the breaker will go at 15A. Worst-case scenario you just trip the breaker that should have been off to begin with, and might save your ass.
Neon testers/screwdrivers are perfectly safe and very practical : you need only one hand to test the presence of the mains voltage.
How you should use them : first make sure it's working by probing an outlet you know for sure is live. If it lights up, only then you can check unknown circuit.
That's because those testers can fail in which case you could test an outlet under voltage and neon wouldn't light up, getting you shocked by believing there's no voltage.
Two pole testers are much more dangerous and require two hands.
Have you not witnessed a situation in which neutral wire is cut off ?
I certainly have.
So, your two handed tester doesn't light up because there's no voltage differential, no current return path (broken neutral), but : there is live mains still present.
You assume there's no voltage in that circuit and, .....
John Smith or u could find a earth . jus to be safe
Szakembőr TV TMIAE
Of course there is. The current flows in both directions, yes. But there is indeed a current return needed. Because you need two poles to create a voltage differential. In case of the neon tester, you are grounded, and therefore you already have the "neutral" potential. A small amount of current will flow through the neon/resistor.
The plastic tester works like an antenna which receives the 50Hz/60Hz electromagnetic pulses/waves from the socket. BOTH only work on the live wire, not neutral or GND(which as far as i know, is a second connection to the earth, neutral is connected to it as well)
If you are NOT grounded, e.g. wearing insulated shoes, the tester will probably not light up. (Maybe, the tester WILL light up because of the EMI)
EDIT: my fault, it will light up, because of human body capacitance. But the current through the neon greatly depends on things surrounding you and the texture of the floor.
If you are testing household ac wall socket circuit only, you are right, it is almost safe, but in case if the circuit involve any ac voltage less than the ignition voltage of the neon blub, you may get a good kick from it. Some old pa system may be?
My dad has a screwdriver like that for detecting mains that he still uses. I suppose they were all the rage in 1958 or so.
I have one where I removed it's internals and use it just as a screwdriver.
I see your work bench has something in common with mine, a Feedback signal generator! I didn't think there would be many about. I worked for Feedback for a while.
I love the phase tester for identifying the switched live from a constant live.
And why is that?
@@rod9311 Probably because it´s way easier to hold the tester in one hand while the other hand operates the switch compared to with a multimeter.
Useful video. Thanks for sharing. Might just have saved me a nasty shock!
Thanks for your video. Never mind the dislikes... idiots deserve what's eventually going to happen when they continue to use the rubbish screwdriver. A multimeter is like £10 from Screwfix, I got one for £12 at B&Q, and it's much more useful as you can also measure voltage in batteries. These screwdriver things are like £2, why not pay £7 or £10 more and get a proper device to measure it? The hospital bill (or funeral) would certainly cost a lot more.
£10.00 multimeters are good for 12v electronics projects, if you are testing at mains supply voltage then pay alot more for ones that are designed for it, they are properly fused and offer a very good degree of protection if you short probes out across the line and neutral, stops you getting injured!
today i was testing a socket outlet with one of those screwdriver testing things and i could feel the ac pulse coming through it , i had used it before many times and it didn't do it. it was stored in a shed so maybe it got damp inside it ?
there perfectly fine to use just dont cheap out on the one you buy...and the one john is using in the vid looks poor quality i mean who makes the light orange with the casing of the screwdriver a similar colour...also ensure you put the screwdriver directly on the source ur testing he should of put it on the screw of the terminal block
I just couldn't get anything dangerous to happen when touching the end. I blew the 1M resistor with 3000V but still it only allows 2mA through with a much brighter neon. The only danger is that its unreliable.
It is called a phase tester for a reason mate - if you switch the phase around, obviously it's not going to detect on neutral. Measure neutral to ground with your multimeter and phase to ground, same issue, init?
You use these in both, not just one.
that device to test live position on your socket, I use that a thousand time and very useful and I never electrocute by this device.
Somebody I know has a screwdriver like that which lights up just with a circuit from your body, hand to hand, so it is used for continuity. I was surprised.
no thats something different... if its used to check continuity you would shock when checking the mains power
So many of the types of comments below are why a growing number of TH-cam video posts are turning off their comments section. Boringly rude, often arrogant, self aggrandising statements. Or, brain farts, as Bill Maher would say. Why can not people be more civil towards each other. Less of the aggression and more of the intellect.
Would I be right in thinking that the 'safe' two pole tester will not work if there is a fault on neutral?
No, it includes single pole detection for voltage using capacitive coupling through the plastic case. Doesn't show actual voltage level in that case but will show visual and audible alarm that voltage is present.
I once read a letter in the comments section of a MAJOR electronics magazine describing the authors home made antistatic wristband design. It was a metallic bracelet with a 12 gauge wire connected to electrical conduit. No mention of a megohm resistor in series with the wire. Not one of the "editors" caught this mess.
Sounds like something you'd see in Make:
Thanks to you.
waiting for next video
I'd trust the neon 10 times before i trust that other tester that runs off a battery, what if the battery's out?
A multimeter is good and well, but you don't always have one handy.
I've never heard of the neon things actually fail, but I see the case that if you dip it in salt-water it might, so I won't do that.
Generally, if I can help it, I won't touch anything but the insulation even if I'm positive the power is off.
Lastly, I've gotten shocked of 230v many times, sometimes because I didn't have this, sometimes because I didn't care to test, and once because a idiot saw the mains was turned off and decided to be a good neighbor and turn it back on for me. it stings good, but it normally won't kill a otherwise healthy man. I'm not suggesting anyone should try, but its not instant death or agonizing pain for hours, it just stings for a second.
+Renax the Man Depends if you have some kind of RCD device fitted in your electrical system...not all properties do!
+Zeamus634 it depends on how well grounded you are. People wearing cheap shoes need not apply for electrical work.
Can i ask where u get your degree holder?
Thank you very, very much for this!
Why are you saying thanks? Read the comments by the electricians, we think this is a BS vid.
I've been using these since I was apprentice over 30 years ago. I've lost or given away many, but never had one break on me. These days I order them five at a time so I make sure I have one in my tool pouch, my spare pool pouch, my truck tool drawer, and two in my basement -just in case I lose one.
Don't be fooled, it's a great tool. :-)
@@SwingboyPA Haha, I believe you :) and appreciate your input here :p
Looks like he is just trying to promote something. These screwdrivers have been in existence for many decades.
Not John Ward mate, when he speaks we listen!
With a 2 probe you go R1 to CPC to determine live cable ???
These things are only for indicating the live. Theyre not saying "Its safe to touch that wire"
It would be plain stupid to touch any mains wiring, no matter if its theoretically safe, some electricians mix up the colors, especially in switches and things tend to get messy. Thats where this thing comes in handy. Resistors like that are safe if they passed the qc
+drkastenbrot true.. Electricity doesn't care what the color of the wire is.