Another dangerous 'corn cob' LED lamp using a dropper circuit, described and expertly tested by AintBigAintClever here: kzfaq.info/get/bejne/pJmTnJef0bHMdZ8.html

7 years later, youtube, let's recommend this video now

I bought a batch of GU10 LEDs about 12 months ago and stupidly proceeded to fit them with the lighting circuit live, the first one was fitted without incident but the second gave me quite an invigorating "tickle" across the major organs! (I was holding the earthed metallic luminaire with one hand as I fitted the bulb). Fortunately I was saved from coronary failure by the distribution box RCD tripping - I WAS LUCKY! Once my heart rhythm had returned to something near nomal I decided it might be prudent to fit the rest of the bulbs with the circuit dead and then being of an inquisitive nature tested for voltage to ground on the bulb heat sinks; I found voltages ranging from 18v to 190v AC with over 50% of them over 140v, the one that bit me had a touch voltage of 180v on the heatsink. Oh and of course they had CE stickers. BE CAREFUL there is some seriously dodgy electrical equipment in circulation these days. Cheap imports from good old China may not always be the bargain they appear. Sorry for the length!

would have been good to put your meter across to show the voltage

and that's why turning power off when replacing light bulb is your first step

50% chance of death, eh? I like them odds, Mister!

Thanks for this video. Nice to know your out there attempting to keep us alive. Cheers from across the pond in Newfoundland, Canada

A girl was killed here recently in Melbourne, Australia, it appears she bought a cheap, unapproved switching iPhone charger from the local market, and was charging the iPhone and wearing a headset while using a laptop. It appears the cheap charger mulfunctioned internally, and sent 240v through the iPhone and headset which sadly resulted in her being fatally electrocuted. How this untested, unapproved stuff is allowed through the borders, and allowed to be sold, is really unacceptable. Government used to be very strict and crack down on this stuff, it appears they have just given up trying.. so be careful.

Fancy a nasty shock?

*EDIT:* This post originally read "Remind me not to buy lighting from China." it should probably read "Remind me to check the reviews of a product before I purchase it" However, several commenters have pointed out that shoddy merchandise or electrical components could be made in any country. My original post was a bit Jingoistic on my part, however I am leaving it up because It is a mistake that I made, and I don't hide my mistakes.

Julian I must say I learn a lot from you!! thank you very much . do you think people in regular market sell it too ? ( same model )

Julian, Great video and quite educational. Thanks.

This was so educational. Thanks a bundle!

What's with all the dislikes on this video? Was the whole staff of the manufacturer forced to downvote it?

Great video! now i know what to look out for when buying my first led gu10

Thank you very much Julian Ilett for this informative video, it might save someone's life.

Never seen one without a lense over the LEDs!

Superb review Julian. Aluminium power plate has been in use for around 20 years in my experience, (I saw them used back then for the power stages of industrial motor drives, and they are now widely used for power LEDs too). They are basically single sided PCBs but with an aluminium substrate rather than FR4 or phenolic resin. The insulating layer is a ceramic, and when manufactured under carefully controlled conditions, has a good withstand voltage rating. Power plates are excellent design solutions for many applications requiring good thermal management. However, I would never trust such a thing as safety insulation unless it had a UL rating or similar, (which I've never seen), and I'm sure cheap Chinese jobs like this have nothing of the sort. You are absolutely right about the danger of electric shock here. Have you notified Trading Standards of where you bought this?

So I guess licking it would be out of the question then? I need a bulb I can safely lick.

The circuit works as follows. The large ceramic cap and 360k resistor work as an RC time constant to passes enough current to the bridge to charge the electrolytic filter cap and create filtered dc current for the LEDs. The rub comes from the fact that the entire circuit can be installed backward resulting in an equally functional but very dangerous situation where the entire unit is referenced to line voltage instead of to ground. Good catch Julian. I hope you didn't find it the hard way. :P

rectifier bridge means AC is rectified to dc before exit to circuit

I'd separate the LED disc and apply the appropriate DC power to it. Might be good for a mobile spotlight or for camping.

Hi, Julian. Thanks so much for sharing this with us. I'm curious to find out what you might think of CREE LED bulbs.

Julian, I bought some similar SMD LED bulbs from ebay in Nov 2013. On Ebay it was claimed they had CE Certification. When they arrived I took the precaution of checking out the metal outer case with a voltmeter and discovered 3 out of 10 bulbs with mains voltage on the outer metal case. After (easily) opening one of the bulbs I found a similar problem to the one you highlight in your video. I my case the issue was tiny screws holding the PCB in place had caused a short to the metal work. I tried warning the supplier but they were not interested so I reported it to trading standards. Impressively, their reaction was swift. They purchased the same bulbs, had them checked and then raided the sellers premises in the UK seizing all their very considerable stock. They later showed me copies of the purported certification which was laughable. Problem is, as they said to me, whilst Ebay continue to allow these companies to trade closing them down is almost imposable, they simply set up again the next day under a different name. With regards the Home bargains lamps mentioned by AintBigAnitClever, I have bought some of these and was impressed. They have a ceramic base and a solid glass body so are well insulated and can't be easly taken apart. So far they have worked well. Keep up the good work with large LED's. I'm playing with them too and your videos are a great help. Purclewan.

If the circuit uses a full wave bridge rectifier and a capacitive dropper then the voltage on the plate is in theory a low DC voltage, not mains although its non isolated and should be double insulated. There is no 50-50 issue though either. It doesn't matter which way around the bulb is plugged into the mains live is always directed to the dropper first via the rectifier diodes in the front half of the bridge, not directly to the plate. Insulation or the lack of it makes the design potentially dangerous.

I'm not sure what is going on when some claim this is scaremongering, but maybe it's an expression of hopeless ignorance (sorry). Any circuit powered by> mains supply< without transformer carries hazardous voltages whether there are rectifiers, resistors, capacitors and what else included. Such circuits are only safe if they are installed in isolated box with at least 8mm safe distance from the curcuit (legal requirements) to any conducting material that can be touched and it's obviously not here. I have worked with electronics for 50 years ...I have learned something. To all doubters ... please accept dangerous voltage despite the diodes are operated with low voltage. So it is with these circuits that I learned already when I was 14 years old.

Thank you - good video. I subscribed.

Excellent review, wow it's amazing this thing is on the market.

How would the LED's work with the current going in the opposite direction? LED's only work in one direction so how can it be 50/50?

You plug it in 220V and on the other end you get 12V so it is not killing power there in that bulb(thats is why you got a diode,capacitor and resistor in it) , so did you measure voltage on the other end??? When you do share the results with us! :D

Thanks for sharing this important safety info!

my GU10 LED is like that but is as a glass cover over it, will the glass make is safe?

More dangerous shite from China. Bloody good illumination, let down by shoddy design. To silence all the "it's not as dangerous as it looks" folks, I'd suggest testing it with a probe attached to an incandescent light bulb rather than a meter or neon screwdriver. If the bulb lights, there's no argument - the bloody thing's live. Very tempted to buy a load of random ones from eBay and put them to the test, especially as not all GU10s end up out-of-reach, they can find their way into desk lamps and other easily-accessible locations (a friend of mine has GU10s in a sloping attic wall/ceiling).

It would have been nice if he showed us the danger with a multimeter. Talk is cheap. So are multimeters.

It sure does! I had my first (and last) major shock when I was about 12 years old. I put an inline connector into a TV lead and decided to open it up. I thought I was opening the TV side, but it turned out to be the still-connected mains side. I'm pretty sure (if I remember this correctly) I grabbed one connector with one hand and the other with the other. It was one hell of a belt, and threw me back across the room. Felt quite wobbly for an hour or so. Pretty lucky to survive that one I reckon.

Thanks for this information and presenting it so sensibly.

Always thought it was interesting how you guys across the pond pronounce Aluminum. 3:09 Well done video, good narration

i don't mean to troll, but doesn't the bridge rectifier prevent that from happening?

And that's why big name-brand manufacturers mold their products together to discourage people from dismantling them and finding the serious risks that lie within. Good show, I hope manufacturers take notice!

Appreciate the breakdown on this, you've probably prevented some nasty accidents!

and you didn't even try to plug the voltmeter to the metal round thing to check if it was really running power

Great review Julian! There is a lot of misconception here about the way AC works, and Isolation. First off.... A bridge rectifier provides NO ISOLATION, full wave or half wave. The diodes are connected directly to the mains, and the rectifier's job is to change AC to DC. This is all the 4 diodes do in a full wave configuration. The only way to isolate you from the mains is to use an isolation transformer. Those two exposed wires on the top of that lamp carry DC, completely un-isolated from the mains. Secondly.... AC in most houses, has what is called "Neutral Phase" which is simply the center tap of the secondary winding on the pole transformer. By making neutral phase, common in every house, reduces electric shock by keeping this a Common Situation between all houses..... Hence: "Common." Here's where people get confused, AC is alternating, which means that both sides of your outlet are really hot, only at one half of the cycle. The large slot here in North America is Neutral Phase or Common, or the center tap of the tranny on the pole. The small slot is called "hot" because it is one outer leg of the pole transformer's secondary. Again, both hot and neutral are alternating meaning at one point of the cycle, the neutral could actually be called Hot. Realistically, in all AC outlets, at one half of the cycle, one side, or the other, is hot. This applies to everywhere in the world. Hope This Helps.

Excellent video!

Really well spotted, thanks for sharing. I try to avoid anything with 'nese in it, but sometimes at their prices, you just can't resist... Keep 'em coming :)

it doesn't matter which way round the input is as the output of a bridge rectifier is always the same. bridge rectifiers not only convert AC to DC but also polarize the output in the correct way regardless of input

One way to tell if the live is wrong is to tap to exposed metal quickly with a least favourite finger. If it hurts the switch off and turn the bulb around. This tip comes courtesy of Darwin Awards Safety At Work Videos 1958.

This is good information. I installed 3 similar bulbs I bought from ebay in each of my 2 kitchen light fittings. One of them literally blew up in the light fitting, shattering the glass face and shooting glass shards and the inner workings of the bulb, all over the kitchen. Furthermore, the remaining bulb contents which were now hanging from the ceiling light fitting, actually caught fire and there was a bare flame dangling from my kitchen ceiling. I immediately removed the bulbs from each fitting and reported them to the local fire service who have told me to talk to trading standards to have them analysed. Nothing came of that though. Beware!

Julian thanks very interesting video about safety since some of us just buy stuff thinking its been tested for safety already then end up injured. Gonna watch out what I buy now. Thanks keep it up man!

noice video but you should have actually demonstrated it by plugging it in the wrong way and measuring voltage and current at the heat sink.

I am an electrical engineer with several years experience designing power electronics so I can speak with some authority on this subject. Now while I may not agree entirely with everything said in this video, I must say that anybody arguing that somehow the connections to the LEDs on the front panel are safe is propagating misinformation and making themselves and others candidates for a Darwin Award. Anything connected to mains is considered a 'hazardous voltage' until it is isolated by an appropriate barrier. A transformer is one way, but there are others. This lamp has NO ISOLATION between the mains and 'accessible conductive parts'. The electrical safety standards do not allow for this. This lamp would never achieve compliance with any electrical safety standard I know of. But while you are considering this lamp have you ever looked inside a phone charger. The type with a USB socket on the side? I can tell you now, they should meet EN60950 (almost everywhere except Germany who use a VDE standard) which requires the primary (mains) conductive parts on the pcb and the conductive secondary (5V output) parts on the pcb to have a minimum clear space between them of not less than 6.4mm across the surface of the pcb or 3.2mm in air provided the parts are well anchored (so they cannot move closer together even if the thing is dropped or hit). I have yet to find a phone charger that meets EN60950. Typical clearances are not 6.4mm, but in some cases even less than 1mm. This lamp is no better and may be worse except for the fact that lamps are not usually so easily touched Whether this lamp gives you a shock or not is a matter of luck more than anything else. There is very little that need go wrong before this lamp would be dangerous to touch while powered. If you are a budding electronics enthusiast, that's great but don't start talking about things of which you clearly know very little. Julian may not be 100% accurate, but anybody arguing that he's 100% wrong is an idiot. Just think about this: what separates the mains voltage from the exposed conductive parts? Here's an acid test to see what you really think of the isolation barrier: would you be happy with your child for example playing with something connected to mains and having only that same thing separating the mains from your child? If you still think this lamp is ok then I am bewildered by the fact that you have survived long enough to be old enough and managed enough education to use a computer to make your stupid posts on here. I mean, what are the chances!?

the mains power is being reduced by the time it comes out the two wires that touch the leds. so like someone mentioned below you wouldnt be getting shocked with the power of the outlet -- just whats being given to the bulbs. not likely to be much.... possibly enough that the few microns of insulation can handle it.

Great Vid Juilan

difference of 220V and 120V lies in the 120 forcing the muscles to contract as opposed to 220 actually pushing you away. doesn't the 220 there lie with 110 on each leg? I am not sure of the configuration of the AC where you are from, but in the US, one leg is 110 and the other is neutral (tied to ground at fuse box). The power is going through a rectifier and filtered by the caps and limited by the resister circuitry. Have you actually measured the voltages you are speaking about or are you merely theorizing based on the AC characteristics there? I see some issues with the ground (reference) being lifted or modified as the delivery voltage is dropped to around 12VDC for the LEDs to work properly... remember that reverse current through an LED even of minuscule amount is death for them, so we are talking DC on the output side you are examining.. even if it is ripply and not filtered completely out. I am not doubting your conclusions because I do not know the circuitry you are examining, but I have looked at some COBB lights here in the US.. but they are 110V units with E27 connections. Here they are isolated via a cap, so ground reference is removed (which I think you are eluding to as the shock hazard if I understand correctly).. Can you provide a schematic of your bulb for more clarification as a way to help understand the concerns? I am trying to understand how you are seeing full AC (or even half-rectified AC) at the LED leads exactly without the LEDs turning into tiny mushroom clouds... :-)

Unbelievably unsafe. Also unsafe are the comments being made by people who think they understand electronics. 1. IF the circuit does not have a voltage limiter - it is simply limiting the current to prevent frying the leds. The LEDS themselves will clamp the voltage across them to a 'lower level'. But if a led dies and the circuit goes open , then the voltage on those terminal will rise to mains and supply the same current that the leds needed - presumably more than 30mA. The 370K resistor would only allow 0.6mA to pass - nowhere near enough to power the leds. It is probably used to discharge the cap - preventing a shock from the terminals if unplugged. It's in the right position to assume that. That means the current is only limited by the capacitor as normal for a dropper like this - the diode ... well that just gives you a DC shock instead! Didn't look like the cap was a safety X or Y rated one - so could go short circuit .. even more current - or fire. 2. It cannot possibly be deemed safe if there is no protection against touching any 'directly live' terminal - regardless of where its fitted. 3. Safe design considers what happens if a part fails ..

This video is mentioned at the beginning of the main article in this month's Lux Magazine. Well done Mr Ilett

I love your vids. which gu10 led spots would you recommend for a 12 foot high ceiling?

I'll take your dodgy GU10 bulb and raise you two dodgy houses I've lived in where the light switches cut off the neutral instead of the live. Imagine the consequences of both combined! :-)

You're obviously an electronics guy. Instead of telling us how bad it is, why don't you show us how bad it is. Put a meter across the leads on the face plate. Then put a meter between each of them and ground. It would do several things, including putting all the fighting to a swift end, showing exactly how much potential is there, and show how dangerous it is. 4:34 of telling us it's bad, you couldn't find 15 seconds to meter it?

Why not plug it in, show the voltage on a meter if it is lethal?

Thanks for this, saw these for sale at a major retailer, opted for Phillips.

wtf are you talking about poles in an AC device? either end should be hot every 1/50th of a second...

Well it's not mains voltage at the LED's is it so I don't get what your on about. What are the actual voltage of those LED's? Whatever they are it won't be over 12 volts, probably more like 4.5 volts and it's DC. I'll stick my tongue across those connection points any way round you want to plug it in and enjoy the pleasant tingle!

Just curious. If you cut out the intermediary circuitry, would this be work from a 12V battery and would it be bright enough for a camper. Obviously with the lower voltages and DC, it would be much safer im thinking?

In other news, I strongly like your videos about stuff like this and all other electronics. Keep It Up, Julian!

This whole video can be debunked in the first 3 minutes. He says it himself "There is a bridge rectifier, a smoothing cap, and electrolytic cap". The bridge rectifier immediately converts mains to DC. He then goes on to say that mains AC will be on the terminal 50 percent of the time you plug it in depending on which way you plug it in. Not true. The bridge rectifier rectifies both halves of the AC wave and combines them into DC before any of the other circuit. Lastly... electrolytics blow up when you hook them up backwards. LOL. Simple

I saw one diode. I didn't see a bridge rectifier.

thanks for sharing this. this is very useful.

Might be more than met your eye on the tiny drop circuit. Perhaps a voltage tester on those front contacts showing a reading would be more convincing since LED generally are not a direct connect to 220-240v.

This would fail CE and C-Tick approvals. This would make the product ILLEGAL in pretty-much the whole country...

Useless information and hypothetical. Do make a REAL test with a multimeter touching the heatsink? I changed over 200 bulbs of this type in 110v and 220v and none have electrocuted me.

That makes perfect sense I am an electrician and we had to change a load of these one day at a pub. The customer had brought them cheap an i did receive a shock of one, it was a down lighter so i presumed id touched the terminals at the top. But when looked they were all covered. I took the lamp out put it back in, turned power back on couldn't find any problem. Bet that's what had happened

WOW! Life saving video. Thank you very much!

Very interesting; unbelievable that this products is on sale.

This is why I only will buy UL tested lights (underwriter laboratories)

No, the heatsink isn't actually live because of the few microns of insulation on the LED plate. But the two connection points on the front of the plate are live.

Thank you. I am an electrician by trade. I didn't know this. Yet have been of many jobs using GU10s and similar lamps. The companies I tended to work for were primary builders, so we generally fitted the filament lamps, leaving it to the customer to change later. This is definitely something to remember.

Nasty. Just like the bad old days of live chassis TVs. I got a nasty shock from a record player in France because of their non-polarised mains... I've bought several dodgy Chinese LED products - but knowingly - I didn't really expect any MR16 to be a genuine 12 watts - but I was shocked to find Amazon warehousing them.

I stumbled upon your video here in the dredges of KZfaq. Thanks for posting. Unfortunately, you do not appear to understand how LED's (or diodes in general) work. I confess that I didn't read all of the replies or comments here, but on the first page no one mentions that diodes only accept voltage in ONE direction. Even though you can cross wire the input, the voltage to the diode remains the same. If by some chance that the + is on those exposed leads, it could pose some risk to you though likely not deadly. Consider a diode to be a type of check valve if you were dealing with a fluid in a pipe. They can be used to convert AC voltage to DC, since they only allow passage of voltage in one direction.

Thanks for sharing this....

Fantastic , a real good reason for purchasing a all included embedded product. The comments about not touching shows a lack of understanding.

These are _perfectly safe._ Remember LED's are _low impedance diodes_ fed through a _dropping resistor._ Assuming that the LED's are run in _series_ There will _never_ be more than *_27 volts_* present at the point you touched.

scaremongering BS a white led has a Vf of about 3.5v DC. If it had 230v ac it would fry. It's a classic transformerless power supply/series capacitor and dropper resistor with bridge rectifier and probably a zener to regulate the probable 12v dc that appears across the front plate on the pink and white. Don't believe me ? put your tongue across it then

whats the lumen output looks super bright & wutsx the wattage use where did u order them from ??

curious could I cut the wires of this and hook it up to meanwell led driver and be good as long as the driver supplies correct voltage and current.

After reading some of the comments, I'm beginning to really concern myself with the intelligence level of mankind?

I used to use a tyre machine outside, 240 v straight up my arm every time it rained wheather I was standing on a big rubber mat or not and I'm still here ..come to think of it I've had cancer twice, i've smashed into the front wing of a car doing 30 mph on a pushbike, stuck a moped into a tree, stuffed many cars into trees - bushes, once jumped over armco sideways in a 2 litre mondeo, fell down an open manhole, fell off a horse, and I've kicked the shit out of many a bigger seeming man than me, and vive versa there isn't an Un dangerous light bulb on the planet - why pick on this one? plug it in and let the house fuses decide if it's dangerous or not. better to light a single candle than rally around in the dark .

Is it not DC voltage on the front of the bulb on the two point you call lethal? If not then what is the transformer for?

Thanks I loved the video! I use those light to give my plants the sunshine ☀️! I hope to see more of the videos!! Thanks lizard

Please. This is bs and you know it.

He talks first of a bridge rectifier, unsmoothed that would give pulsating DC. Then there's a dropper resistor + cap (still DC) and I suspect a parallel zener to the final small electrolytic cap (if it's 1100uf it's certainly not 400v!). Now we have a smooth DC Voltage to match the LEDs' requirements.. Let's prove the danger is there by connecting a meter to Earth. This is what he should have done rather than scaremongering.

just to point out it does matter what way round you plug it in it AC current. this means alternating it swaps between live and neutral at around 50 to hertz (per second) so if this basics of electronic principle evades you then please don't comment. the holder that is clipped onto thw desk has two exposed points that's where the bulb goes in you should never change a bulb with the power on Also it's never the voltage that kills its the amps. you can grab 240v mains in your hand and let go (speaking from experience here) that's my rant over

Thanks so much for the information. It helps a lot!!!

Why is anyone questioning this- the design is clearly dangerous. A little knowledge is a dangerous thing as some of the replies demonstrate. Hope you have a split load CU to cover your lighting. Before you criticise the video go and learn a bit more about electronics.... oh and it IS a 360K resistor. Thank you for sharing this.

Please put a stipulation in your description or just take the video down all together. The information you are presenting is incorrect. The components in the back of the bulb do 2 things: 1- drop the voltage and 2- rectify the current from AD to DC. Additionally, LED lights only work in one direction (+ must go to + and - to -), this is the purpose of a diode (light emitting or otherwise). This light bulb can't be considered dangerous. At least in the sense you describe.

A lot of the negative comments seem to assume that the lowish voltage at the LEDs is galvanically isolated from the mains voltage as though there was an isolating transformer in it.. Also many of us that have had electric shocks tend to feel that we will get away unscathed every time. The truth is that without unsafe equipment or working practices we would not have had the shocks in the first place. The uploader was right to point out that there is very little clearance between a high voltage point and the metal work... many of these little spotlights are used in kitchens and bathrooms which can have high humidity and generally be more hazardous. I have similar lamps to these in my kitchen, not the same construction but they are madly efficient and I was getting tired of changing halogen lamps...

Wow, Thanks for the Heads-up, very nice of you.!

What the heck is 3 quid?

Wow. You need to quit biting you fingernails.

Hello , cool video. thx for that, the one I ordered didn't work at all. So what could we do to modify it to have it working in a safe way? because the technology is not bad, the one I have is supposed to be good color to use on house plants so possibility to make really cool decoration with living plants in your house. if only it was safe.

I'm assuming that the ac first runs into the rectifier, if so the positive dc voltage would run through the resister no matter which way you insert it. Switching up the input on a fwbr does not switch the output.