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New Dell Laptops Give Users a Literal Shock
An anonymous reader writes "According to CNET.co.uk, certain new Dell laptops with a brushed-aluminum finish are giving users more than they bargained for. 'We know this because several CNET staff were hit with an electrical charge while using Dell's new XPS M1530 — and we're not the only ones. Dell's forums are littered with user complaints about the shocking experiences they've had with some systems. The problem only seems to occur in Dell laptops that have a brushed-aluminum finish. These include the XPS M1330 and XPS M1530. It's caused by the two-pronged connection between the mains lead and the power adapter, which isn't earthed properly because of its lack of a third pin. The laptop therefore exhibits an electrical potential (voltage) between its exposed metal parts (the brushed aluminum wrist pad) and earth ground. Since there is no earth, the human body basically acts as a wire that can conduct electric current, hence the tingling, jolting sensation.'"
This is the new ground breaking experience with laptops!
"That means people who get Dells will have SHOCKING Personalities!" Looks like Dell has been amping up their marketing department. Just remember, "It's not a bug, it's a feature!"
Give a man a fire and he'll be warm for a day. But light a man on fire and he'll be warm for the rest of his life.
Where can I get one? I need a presant for my mother in law.
Someone save me from this sanity.
To be fair to Dell this happened on my PowerBook and not so much on my MacBook Pro... But sometime I do get a tingle, in the right condition.
If something is so important that you feel the need to post it on the internet... It probably isn't that important.
...what happens when you lick it?
Better or worse than a 9V battery?
In Soviet Russia, laptops shock you.
"Dude, you've got a Dell!"
Windows 3.1x calc: 3.11 - 3.10 = 0.00
The Apple PowerBook G4 aluminium systems have also suffered from this - but only when using the 2-pronged power plug. If I use the actual cable between the power adaptor and the wall (with three pins) then this is no longer an issue.
I believe the MacBook Pros also suffer from this however I haven't tested this.
My room has some carpet, and if I walk across it and start typing on my Inspiron 1720, sometimes I get shocks from the edge of the keyboard tray, I guess there is a little bit of exposed metal around the edge. Its probably not a design flaw though, it seems to deal with the charge fine. :)
Another shocking aspect is how well it runs linux! Everything worked
Obligatory blog plug: http://www.caseybanner.ca/
Don't shock me bro!
Knowledge is power. Knowledge shared is power lost.
The exploding / burning batteries, or the electric shock?
I think I'll stick to my ThinkPad, thank you much...
Damn_registrars has no butt-hole. Damn_registrars has no use for a butt-hole.
I've had an aluminum-brushed XPS m1330 for about four months now, and I've never experienced a "shock" like the article is suggesting. I don't doubt that the CNET editors have experienced this, but I'm certain I would have remembered it if it had happened to me.
I checked, and my 1330 has a grounded three-prong plug going into the wall, and a three-prong plug going in to the power brick. Maybe the UK 1330s/1530s are different than the American ones?
The machines have struck the first blow!
If you can read this, I forgot to post anonymously.
the two-pronged connection between the mains lead and the power adapter, which isn't earthed properly because of its lack of a third pin.
That explanation is over simplified. Tons of metal-encased devices have only two-prong leads and are perfectly safe. My Apple laptop for one, and a lot of stereo equipment as well.
UL allows this if the device is sufficiently isolated. What is sufficient depends on the type of device, the type of power supply, whether the supply is internal or external, and so on. Usually it means that the DC output of the power supply has a very high impedance with respect its input, and also that the metal chassis of the device is floating (with specific distances and or dielectics between it and any possible potential) and/or has a non-conductive finish. I'm not sure but I think even just clear anodizing would meet that requirement. I just tested my MacBook and all the aluminum surfaces are not conductive, suggesting such a finish.
In order for the Dells to be zapping people they must have doubly screwed the pooch: wall wart is putting out a high potential, AND the case is not properly insulated.
isn't this a major oversight by the UL? It's one thing when batteries catch fire, but certainly something completely different when basic Electrical Safety 101 issues like chassis ground are violated.
It keeps you awake in those meetings that seem to take *forever*.
Just keep in touch with your Dell laptop.
Windows 2000 - from the guys who brought us edlin
I guess you could say that the folks who bought these laptops got a shockingly good deal.
Do or do not. There is no try. --Jedi Master Yoda
"We deny all charges."
Authority questions you. Return the favor.
You know, whenever I stick a kitchen fork into an electrical socket I get shocked too. Must be a defect in the design of those forks.
...after all, no part of the casing *should* be making contact with the electrical parts at all. The whole thing with making the casing grounded is for the unfortunate event that it does; typically as the result of some manner of physical malfunction within (e.g. a wire coming loose).
That said - my acer laptop has a brushed aluminum finish and has the same problem *if* I don't plug it into a grounded wall outlet (as it currently isn't). It doesn't feel so much like a jolt or a tingle, however, as that the surface feels strange.. almost like it's vibrating at a high frequency; but only when touched very, very lightly.. a firm touch increases contact area and away goes that odd feel.
Surprisingly, the metallic finish (probably aluminum as well) on my USB keyboard has the same thing going on.
Again, though, if plugged into a proper outlet, the problem goes away.
It seems fairly common for the housings of low-power (and yes, a laptop is pretty much low power; although a 'jolt' sounds light it might be otherwise.. high performance gaming laptop sucking 150W+ perhaps?) to not be properly insulated, though.. I can probably walk around the house and find a dozen more appliances that exhibit this.
I have experienced similar shocks with computing devices not using an earth ground. I first noticed this with a USB drive enclosure with an aluminum case. I noticed a tingle when I touched the case while touching a grounded object. The voltage measured 53VAC.
Another incident happened when connecting an LCD monitor to a system. Both LCD and computer were off, but plugged into different outlets. When the connector make contact with the VGA port the breaker on one of the outlets tripped.
Just recently I was hooking up an HP printer/scanner/fax to a computer via USB. With my right hand on the case and my left hand grabbing the USB cable I was jolted when my knuckle touched the Outer metal connector. The shock was enough to put a pinhole in the side of my knuckle which is still healing after several weeks.
-Zee
I actually had an issue with Dell laptops shocking me years ago on my inspiron 1150. My laptop kept dying and when I called Dell tech support about it they always ignored the fact that it shocked me and stated that the reason my laptop dying must have been a RAM or a motherboard issue. After 3 times having those parts replaced and it dying shortly after each fix I ultimately got a manager to just send me a new laptop after hours of arguing with them. I honestly don't think I will purchase another product from Dell again. The last item I purchased from them was a monitor and even that ultimately ended up having issues.
Need any dad jokes?
I can't wait to get my hands on one of these. Maybe it could replace the defibrillator implanted in my chest. On second thought, I now know what to get Dick Cheney for his birthday.
tm
Support TBI Research: http://www.raisinhope.org
What a "shocking" experience!
1) It seems as if it's UK only. American ones come with the ground prong on the plug
2) People who complain are getting new plugs with the ground prong and the problem goes away (not that they should have to complain).
3) On the forums linked to in TFA there's a response from "a Dell guy":
To the tingle, you are absolutely correct, it's a grounding thing. Dell product design went from a 3 prong grounded plug at the outlet to a 2 prong "floating ground". The tingle you get is your body feeling the circuit. If you wish to eliminate that sensation, use the system on a solid surface such as a table or put something between the bottom of the system and you that's thicker than typical blue jean or khaki material. If you're more concerned than that the 2 prong adapter can be replaced with a 3 which eliminates it. As full assurance, the voltage you feel is decidely not harmful and there's no risk of electric shock.
Whaa? Even if it's true that it's not dangerous, who the hell wants current running through them all the time? That tingling feeling isn't very pleasant. I know, I've had it from other appliances (and from sticking my tongue on batteries).
Free the Quark 3 from asymptotic confinement! Bring your charm! Don't get down! All colours and flavours welcome!
The engineers giving in to the Helpdesk people.
Think of the possibilities!
Tech: Ok, put your mouse over the 'My computer' Icon and right click...
Guy: Why does this have to be so complicated? Why doesn't everything just work right the first time? You Idiots should be shot!
Tech: Well Sir, if you would just...
Guy: I'm tired of you people and your attitudes, why I should...*ZAP* AHHH! WHAT THE HELL WAS THAT?
Tech: Now what did you learn?
Guy: I'M GONNA KILL...*ZAAP* AHHH!
Tech: A bit slow today are we?
Seriously, why can't electronics manufacturers take the simple step of grounding everything? Why would you use a two pronged plug anymore at all?
This is the perfect computer for all my late night Jolt Cola fueled mis-adventures on the internet! Too bad it couldn't do like new cars and react to the physiological changes that occur as you fall asleep...
That being said I used to have this rugged steel AT case I modded to support my ATX SuperSocket7 motherboard... The mods including kicking the shit out of it while it was on to prove how older tech was more rugged. Long story short that damn thing gave one hell of a jolt any time I touched the metal... It was awesome getting people to turn that bitch on!
I'm sick of following my dreams. I'm just going to ask where they're goin' and hook up with 'em later.
Cut open an unplugged three prog extension cord, exposing the three wires inside.
Cut open Dell power cord, exposing the two wires inside.
Position pieces of heat-shrink tube over the stripped inner wires to be joined.
Connect positive extension cord wire to positive laptop wire and solder.
Connect neg. wire to neg. wire and solder.
Connect the third ground wire to the exterior casing of the laptop with tape as to be removable.
Cover over the sealed three wires with heat shrink or electrical tape for asthetics.
Disclaimer: I'm assuming everyone here knows what they are doing. Mains power can be very hazardous and very deadly. Do NOT attempt this if you are unsure of what you are doing -- call someone more experienced if in doubt. But for those of you who know what you are doing, this should be an easy fix to avoid the shock of you being used for a ground wire.
Windows has detected an undetectable error.
What is this guy trying to say? And what does the non-existence of earth have to do with getting shocked? He needs to get more grounded. :-P
If this had been Dell...oh, carry on..
I'm guessing they probably mean grounded. I've never heard of that term, maybe I'm out of the new slang loop?
God, schmod. I want my monkey man!
I've never heard it put that way before. In US English, we use the word "grounded". Is that a bad transaction from a non native speaker, or is there some place that they use the word earth instead of ground?
Well.. maybe. Or Maybe not. But Definitely not sort of.
I'm not an electrical engineer, but I think you're on the right track there. The third wire is a safety feature: Normally no current flows through it. It is connected to all exposed metal which can come in contact with a deadly potential in the case of a defect. If current flows through the third wire, it's a sign of such a defect and the breaker must disconnect the circuit immediately.
You can get a Dell at this cool website called http://dell.com/
But you can't get any of the ones that shock you. For that, you'll need http://www.tigerdirect/ or http://www.ebay.com/
No guarantees at either of those places!
For laptops that don't shock you, try shopping at Best Buy, where only the PRICE will shock you.
The dangers of knowledge trigger emotional distress in human beings.
excellent for the cooperate business scene, nothing keeps employees awake like an electric shock.
Best to get your facts straight. My m1330 comes with a grounded 3-prong plug and I suspect mine isn't the only one.
My HP does this to me. Sometimes such a shock it is painful.
Neutral is neutral and ground is ground. The fact that they are connected to each other at the service entrance does NOT mean that neutral can be used as a ground reference.
From the device's perspective, neutral must be treated as AC line input, never ever ever as a ground.
Any number of wiring faults could cause the neutral to become hot, and even under normal circumstances it is common to see some potential on neutral relative to ground, because loads on the branch circuit are pulling it towards one phase or the other.
That reminds me, I got something like this on the ThinkPads that I owned (R50, R51). I got an occasional zap (felt like the usual static zap when you rub shoes along a nylon carpet then touch a door). My way of dealing with this was, before I used the computer),to bunch my hand up into a fist (tightens the muscles, which makes the shock hurt less), then touch the front part of the keyboard with the soft part of my hand.
I've had no static problems with my current laptop (which does actually have a grounded power supply, but is also considerably more plastic).
Ask me about repetitive DNA
I have a Dell XPS M1330, and the aluminum keyboard rest area causes my hands to tingle...weirdly though, it only happens when I have a device plugged into the left USB port. A shame that bizarre build/design flaws mar what is otherwise one of the best laptops Dell has ever made.
Static discharge (what you're experiencing here) is worse if the computer case is earthed because this provides a better path. For this reason those "earthing straps" etc used to protect sensitive equipment should be connected through a high resistance (1 M ohms or so) to limit the discharge current.
Engineering is the art of compromise.
Being relatively young, I have only owned 2 laptops so far a Compaq Presario v2310 (which I regret by the way, but it met my needs for the cost), and a Dell Inspiron e1505/6400 (which I am still using, but will replace with a ThinkPad x61t soon). Anyway, I just wanted to say that I have been shocked (pretty good, I might add) by both of these laptops at least once. Note, both of these laptops are in simple plastic cases, not aluminum. When it happens however, my greatest concern has always been the laptop. I actually caused the Compaq to reboot once. The interesting thing is, I'm really not in dry environments typically. I don't usually shock things. As a side note, that Dell is a piece of crap electronically. Any time it is plugged into the wall you get noise out of the speaker/headphones. The Compaq had a similar issue, but the Dell is 10 times worse.
My XPS M1210, which I think is the predecessor to the M1330, does this frequently as well. Though it's mostly plastic, the touchpad and the trim surrounding it, and various metal bits have given me shocks. It's not a fun surprise.
Since the "neutral" line is actually ground as well (it ties to the grounding bar at your breaker panel)
Actually, it totally depends on your local electrical system. In the UK the grounds are usually tied to neutral at a substation. It's also possible for 'ground' to be literally that - a conductive-tipped pole driven deep into the ground somewhere near the property. I'm sure there is variation within the US too.
I've had 2 MacBook Pros (with the brushed finish), and the tingling, electric sensation has happened with both of them when using the unearthed 2-prong adapter.
When plugged in with the longer, 3-prong earthed cable, its not a problem.
This is in Australia (240V as opposed to 110V in the US), so I don't know if that makes it more noticeable or not. I'm guessing not, as the adapter will step the voltage down to the same in both cases.
Combine this with Microsoft's latest patent. Microsoft detects that you're falling asleep and ZAP!
This has happened on my partners Inspiron she bought about 6 months ago. It earths onto her thigh via a screw in the bottom of the case.
Put some blutack over the screw and that sorted it out. This is in Australia. Its annoying how many things aren't earthed properly here.
If a device is not properly grounded or has problems where it provides a small electrical shock, can this be a potential health hazard for people who may have certain types of medical implants - e.g. implanted pacemakers, defibrillators, or other devices?
I suppose any potential threat could be worse if the current were conducted for example - from one hand across the body to the other, so that it would travel across the chest or implant while seeking ground...
When you connect your transformer to the mains, what do you expect? 76kV is way too much power for that small transformer. Try plugging it into line voltage, which here happens to be a measly 120V.
Is that a real poncho? I mean, is that a Mexican poncho or is that a Sears poncho?
As any electrician will tell you, with two phase 110v in the U.S. (most homes and establishments) You have only hot and ground. If you rip open your electrical box you will notice three wires coming in. +120, -120, and ground. All the white wires and grounds get connected to the same buss. The hot (black wire) gets a fuse or breaker to either +120 or -120. (220v appliances get two breakers linked together.)
The people getting a shock probably have their outlet wired incorrectly.
I doubt very much it is Dell's fault. That being said, isolation through a transformer is always a good idea.
The "neutral" is connected to the center tap on the transformer in split phase systems. The ground (green) wire has to be connected to the neutral bus or it would be point less (no return path).
* In sub panels the neutral and ground should never be connected (ground loop)!
* The neutral wire has the same amount of energy running through it as the black wire!
* A GFCI outlet will save you from your shitty Dell. Install them!
http://en.wikipedia.org/wiki/Split_phase
I'm on an Intel iMac with the keyboard with a brushed aluminum finish and I got shocked just posting this. I thought it was the "warming sensation" jelly that was spilled on my keyboard, but now I know better!!!
-
404 - You have reached this sig in error.
I have a Dell Inspiron 8600. The outlet for the power adapter is a three pronged outlet, but when it's plugged into an outlet with only 2 prongs (via a 3-2 prong adapter), then if I touch the lid or bottom....zap. Of course just sitting there with your shoes is no problem, but if you are barefoot and touch the ground while in contact...ouch. The worst part is the mind tricks it plays on you. For example, you will carry it back to a chair on battery power, you plug it in to watch a couple movies, kick off your shoes and relax. After the first movie, up to get some ice cream or a drink. Not remembering getting zapped in the last few hours, you think you are fine. The second your bare feet hit the ground...zap.
clearly, they need a longer cable!
The Kruger Dunning explains most post on
about a year and a half ago, the company i was working for sent me to a class to learn a new software package. the class was taught using dell laptops.
everytime you'd start working on a lesson you'd get zapped.
Yes, the neutral is also tied to ground at the breaker panel, like the ground.
But the thing is the neutral is designed to ALWAYS carry current, it's part of the circuit. The ground is there for safety and usually carries no current.
Why is this important? Well, if ground is at 0V, but the wire between the outlet and ground is 1 ohm and carrying 15 Amps, then the neutral at the outlet will be at 15A * 1 ohm, or 15V (AC in this case). So now there is a voltage difference between neutral and "true" ground (which can be either the ground prong on the outlet or the puddle you're standing in) and that means that you'll have a current flow (shock) between something tied to that neutral and ground.
i.e. you'll get shocked.
The ground usually carries no current, so even with a resistance to true ground, there should be zero current, 1 Ohm * 0A = 0V and you don't feel a shock.
Since this depends on current flow through the neutral at your electrical outlet you'll find this thing will either give you a shock or not depending on which outlet you plug it into and what else is plugged in and turned on.
This is why all two-prong devices are supposed to be "double insulated" (http://en.wikipedia.org/wiki/Double_insulated#Class_II) from both line power and neutral.
http://lkml.org/lkml/2005/8/20/95
Foreign Country In Different Terminology Shock! Mains: the mains electricity or water supply is simply the supply to your home/place of work/etc. Earthed: providing a connection to the Earth; grounded.
And tomorrow the stock exchange will be the human race
The tingle lets you know it is working....
If it works for shampoo, why not laptops.
This is a wild guess, but I've had to re-aim my air purifiers around my house to get around my metal tables zapping me. Indeed it would also zap me through my completely plastic laptop (Dell Inspiron 600m) since my table was sending a nice amount of juice through it every time my air purifier rotated its direction.
So peeps, move your air purifiers.. If they use a powered metal filter you are going to have problems with electrostatic discharge.
EOF
"Little does he know, but there is no 'I' in 'Idiot'!"
Wow I was just about to buy one of these but bought another IBM^H lenovo instead. I considered a dell with linux but only one shitty inspiron model is available with linux. I considered a dell with windows XP but only notebooks with big screens are available with windows XP. So lenovo was it because you can get any thinkpad with windows XP still. anything to avoid vista!
> Actually, it totally depends on your local electrical system.
In the US ground is tied to earth at the service entrance, as is the neutral. Ground and neutral are connected together nowhere else. The service from the utility does not include a ground: just neutral and two 120V lines (240V between them). The utility's neutral is grounded at the transformer.
> I'm sure there is variation within the US too.
I don't believe that there are any jurisdictions in the US that have not adopted the National Electrical Code.
The problem described in the article, if it actually exists, is due to coupling (metallic or capacitive) between the AC line and the metal exterior. It has to do with the absence of a third pin only in that if there was a third pin the metal exterior would be connected to it and therefor could not be hot. There are many double-insulated appliances with two-wire cords and metal exteriors that do not give shocks.
Warning: this article may contain humor, sarcasm, parody, and perhaps even irony. Read at your own risk.
Had my Macbook pro for months now and never one gotten a shock.
I too have a Macbook Pro, and I have felt the tingly sensation of voltage alternating at 60Hz on the outer case. The reason you didn't feel it was that you, yourself, were not grounded and so you didn't complete the circuit. You have to be grounded to the earth ground or the neutral conductor to notice the voltage.
It is common to ground the outer case of electronic devices to the ground of the electronics - that way static discharges to the case don't end up going into expensive semiconductors. Normally this ground connection is not an issue; however, leakage currents can make their way through the power adapter and can apply an AC bias to the "ground" voltage on the DC side of the power supply - so effectively what should be 0VDC actually is floating around 60-70VAC. Because it's a leakage current through the very high resistance between the AC side and the DC side of the power adapter, there usually is very little current (a few microamps) available, so if you complete the circuit to ground via your body, you'll usually only feel a tingle at most. It's really not anything to worry about - more of a curiosity than anything else.
Taking this to a little more of an extreme... back when I was a teenager, my room had a concrete floor with linoleum flooring on it, and I had a 1960s-era Hickok vacuum tube tester with a metal front panel and an unpolarized plug. I was sitting on the floor one day testing vacuum tubes, as teenagers are apt to do, and I noticed that whenever I touched the front panel I felt a strong buzzing sensation in my hand. I unplugged the tube tester, and plugged it back in with the plug rotated 180 degrees and the AC voltage on the front panel was gone. I cut the antique power cord off the next day and installed a grounded plug and power cord.
Putting moderation advice in your
Hey, fanboy. Stop your drooling for a few seconds and re-read that he said it happens with MacBooks. Not *all* Mac Books. It doesn't happen with *all* individual machines in that Dell (or Toshiba, etc) line, either.
There's nothing magical about the components in an Apple laptop (probably using almost the same damn parts) that makes grounding and electricity work differently.
If real is what you can feel, smell, taste and see, then 'real' is simply electrical signals interpreted by your brain. Throughout human history, we have been dependent on machines to survive. Fate, it seems, is not without a sense of irony.
Right before I saw this article, I received yet another shock from my HP dv5000 series laptop. It's been doing this for over a year now, and I was starting to get worried something else in my laptop might fail because of it. It's somewhat reassuring to hear Dell seems to be having the same problem.
Thats because the power supplies have to meet UL and VDE specifications which say that if thousands of volts are present on the AC line, nothing gets through to the computer.
Perhaps what you are experiencing is some AC getting through the RF filter on the power supply. Sometimes there is a very small HV cap between AC side and DC side (i.e. computer)
I guess in summary I would have to say that the power supplies involved are poorly designed and/or faulty.
I bet the tingly feeling people are getting is leakage of the high voltage AC from the inverter for the display backlight.
A cold cathode light uses about 700 volts AC 50hz at 4ma or so. This would definitely feel tingly.
You would not feel 12VDC at all.
"earthed" is British for "grounded".
Warning: this article may contain humor, sarcasm, parody, and perhaps even irony. Read at your own risk.
this is why you buy the Vostro instead. i'm so sick and tired of these hardcore laptops that people waste their money on and it simply breaks or shocks or catches on fire. if you absolutely need a portable machine for something business related, then jesus christ. just buy a god damn Vostro, get the 3 Year NBD warranty with on-site support, and you'll then start to realize why Dell is actually a good computer company..
*plays the Apogee theme song music*
True, but there are a few differences:
1) The ground wire goes to the metal casing of the outlet, not all the way to the grounding bar, to eliminate the possibility of 'floating' voltages or charge buildup along the neutral.
2) The ground wire typically connects directly to the metal case of the device, so that if the hot wire accidentally makes contact with the case inside the device it won't shock the user.
3) Although in principle you could get these benefits from hooking up the neutral to the case and doing away with the ground wire, it would have dire consequences if the user reversed the plug. Therefore the ground plug is triangular and not reversible.
But its true that the ground wire is a holdout from those days when we used to have metal cases on everything (remember those metal drills - and the XPS, apparently). If the hot wire touched the case the user would get a shock, hence the ground prong.
There appears to be an ongoing problem with laptop computer power supplies. Dell has in the past issued recalls on defective power supplies, there have been stories of power supplies melting and catching fire.
Either the problem is that consumers are being sold inferior products that fail to meet the required safety standards, or the standards that currently exist are not sufficient to protect people.
What will it take to stop this happen ? Does someone need to sue a manufacturer, or do we wait until someone dies ?
Put your tongue between the terminals of a 9V battery. Do you experience:
( ) A tingle?
( ) Tongue lock?
(*) Oooh yeah!
Stylish sheet to fix many problems in Slashdot's D3: https://gist.github.com/801524
"Don't Dell me, Bro !!"
In the US and elsewhere, two prong plugs are permitted if the power supply meets the requirements of double insulation. If you are getting a shock, then you have a supply that was probably submitted for testing and approval and then cost reduced by a non North American or non European manufacturer. Odds are, you are seeing an AC capacitive coupling between primary and secondary.
In most three wire power supply designs, this capacitance is eliminated by a ground shield between the primary and seconary. In double insulated designs, this isolation is accomplished by the transformer geometry and interwinding spacing.
It is reasonable to assume that this problem exists because some buyer tried to squeeze a few cents out of the power supply, or some manufacturer did the same thing. In either case, the cheaper design was not properly tested to insure safety.
This is one of the problems with out sourcing, you can never insure your product complies with the appropriate safety standards.
...I had the bright idea of touching a 9 volt battery to my *braces*.
I couldn't tell if the bright white flash/pop that followed came from just in front of my face, or from somewhere inside my head. Painful to say the least.
Can someone explain what happened?
This common "tingle" everyone is referring to is because there is a small (1-10 nF I believe) bleeder cap between neutral and device ground. Since neutral is not exactly ground because it is a current return, or the plug may be in backwards (there is a polarity) this bleeder cap will pass enough current to feel a tingle.
EOF
Well, not anymore. But when the Mac first came out, holy crap, nothing was standard.
Last year, I posted detailed information on the tingling sensation sometimes associated with leakage current http://direct2dell.com/one2one/archive/2007/04/24/8522.aspx. Since the story, I re-visited the issue with members of our Engineering team. Here's what they had to say: Even though the leakage current is extremely low and well within safety limits, it is perceptible by some people. This perception may be experienced as a mild "tingling" effect. However, if that "tingling" effect is coupled with an electrostatic discharge, such as is experienced when walking on carpet in dry conditions, the total effect can be surprising but not harmful. The primary effect being felt is from the electrostatic discharge (static electricity). Typically the tingling sensation can be eliminated with a three-prong adapter, however a three prong grounded AC adapter will not eliminate the electrostatic discharge. The tingle is not harmful to the users or the system components. Again, more details about the tingle sensation are available here. http://direct2dell.com/one2one/archive/2007/04/24/8522.aspx
In Force Feedback.
That sinking feeling deep in your gut when you KNOW you screwed up bad summed up with: {head desk} {head desk}
Reminds me of a trip to Cuba last year. The power in the rooms was 220v, with no ground plug. Many consumer electronics, including my wonderful little Toshiba Libretto (now *that's* a sub-notebook, Apple) work fine on 220, the switching power supply just regulates it properly.
:) Check out the photos.
However, I had to bend the ground pin out of the way to plug it in. Things charged and worked fine. However, apparently the brushed aluminum case wasn't quite at true ground with this arrangement. It was more than tingly (if your feet were on the ground; if you lifted them, it was fine). I made a point of only using the power supply to charge it, then use it on battery power, for safety's sake.
It was interesting to see the cavalier attitude towards electricity down there. A worker was doing some construction with an electric drill outside our room; the drill obviously only took 120v, as he hooked up a transformer in our *bathroom* (which was near the door) to power his drill. It was connected to the plug with wires jammed into the outlet, and to the drill by wires wrapped around the prongs. Scary stuff. We stayed clear of our room that day.
Love many, trust a few, do harm to none.
Is the sensation of a 9 volt battery on the tongue considered to be good or bad to you?
I was sitting on the floor one day testing vacuum tubes, as teenagers are apt to do
Ah yes, gone are the carefree and reckless days of youth.
If moderation could change anything, it would be illegal.
Duh. Magic has nothing to do with good engineering. Oh, wait... this must be someone from Microsoft. In, your case it does.
This is my sig. There are many like it but this one is mine.
c'mon lick it, I triple dog dare you!
My employer supplies us with Dell laptops as work machines, and mine zaps the hell out of me all the time. It's not any worse than your average static zap after shuffling your feet across a carpet, but still
- Roach
But only when the air is dry and I've been walking around on my carpet in my socks. What really is happening most of the time is the charge is so built up in someone's body that the second you touch a metal surface you discharge it, thereby feeling the shock and thereby causing the problem for yourself. By the way, I'm not using a Dell, I'm using an ASUS G2P with a steel plate.
For those who seek perfection there can be no rest on this side of the grave.
Who wouldn't want to read an eBook and NOT FORGET IT!
Damn you Goebels! Damn you %$^BZZT Heil Hitler!!
You want the ground wire to maintain its integrity as long as possible under fault conditions. As long as the ground wire is intact, the case etc cannot reach a potential very much higher than ground, so you can't get a shock. Even if the phase wire somehow shorts inside to ground, you want the ground to maintain the case at ground potential until the switchboard fuse or breaker opens and disconnects the supply.
If the case does get struck by lightning, well, the wire will probably vapourise anyway, and you will be in deep doodoo anyway, but the fuse would not have made things any better. (The vapourised wire and fuse would all keep conducting long enough for the strike to finish anyway, at which time your charred remains will fall to the floor...)
So remember, when a fuse blows or a breaker pops, if you fix it and it goes again, there is a more serious fault somewhere else. Fuses can go from old age, and breakers can open from one off surges, but if they keep popping there is something seriously wrong downstream. Do not replace a fuse with one with a higher rating as a fire may really spoil your day.
Fianlly, the original suggestion of adding an earth has its merits, but needs to be done properly to maintain safety. You really need to check your local regulations before doing this sort of thing. You can void your insurance even if there is no actual problem with the way you have done it. This will depend where you are, and I am probably not in the same country as you so I will not presume to tell you what you are and are not allowed to do.
I suppose that makes sense with desktop PCs, as the user rarely touches the metal parts of the case. But with laptops isn't that poor design? What happens if the power transformer develops an internal short? Couldn't that possibly ground the hot AC thru the case?
tic
It's like aversion therapy!
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To be fair to Dell this happened on my PowerBook and not so much on my MacBook Pro... But sometime I do get a tingle, in the right condition.
I have owned a Powerbook 17" and a Macbook Pro since they came out, used two different ones for work, and set up dozens of them for other people. Never felt this, heard of it from a user, or read about it. Plug your system in using the 3-prong grounded cord, and if the problem continues, you're imagining things or your building is not wired properly- and YES, the power brick is grounded on many (not all) of the square powerbook G4 power adapters, and all of the Magsafe ones; see the big chrome "button" that the power plug snaps into place using? Now look at the three prong cord- see how there's a metal bit in that slot? That grounds the adapter, and the computer.
Seriously: there are probably more Macbook Pros and Powerbooks than any other single design of laptop out there. They change very little from revision to revision, and god knows, Apple people make any sort of problem with their Apple gear very loudly heard.
What you may feel is the case pinching a hair or something- the front edge on some of them has a slight gap, and that gap can close when you put your palms down on the top, for example. The case screws also tend to loosen over time. You can also get pinched by the gap across the top between the plastic edge and the top deck piece of aluminum.
If you see a gap between the case halves up front- remove the battery, and loosen the two screws by the lid latch (use a proper screwdriver size- if it pops out easily from the screw, you have the wrong screwdriver.) Now squeeze the top of the case down and while doing so, tighten the screws. Do the same for each screw on the sides.
If it's not that- it's either a medical condition you have where you feel shocks/pain and you need to get that checked out, or it's simple static electricity. Another possibility is that the plugs in your house/workplace are not wired properly, and you should have a qualified, licensed electrician check.
Please help metamoderate.
The Netherlands - still plenty left in old homes.
Moreover: ungrounded extension cords. Tons of those, and you can still buy them.
Why can you still buy those, you might ask.. because there's still plenty of round plugs that do not have the gaps in the sides so that they will fit in a grounded outlet.
I'm staying over at my folks' at the moment - that's why it's so easy to find them (and why this thing isn't grounded right now). At my own place, I've had ungrounded outlets replaced (I 'am' an EE, but not practicing, so can't legally pull the wires and I only rent) and replaced all ungrounded extension cords myself. I'll probably be doing the same around here when I find some time.
I have a brushed aluminium Macbook Pro at home. Here in Japan power plugs are generally the 2-pronged unearthed type same as the U.S.
At home, we have wooden floors or linoleum-type tyles which insulate, but on a recent trip I discovered that using the macbook with bare feet on a stone floor can be a shocking experience.
The whole outer shell has a buzzy feel when touched, and due to the space between the front of the case and the keyboard, my forearms were constantly getting zapped as I tried to type.
Solution? Wear slippers. That worked for me.
j'ai découvert une démonstration vraiment admirable (de ce théorème général) que cette si
The ground (green) wire has to be connected to the neutral bus or it would be point less (no return path).
Not necessarily true. The ground wire (third prong, etc), simply has to be grounded. There are lots of cases of old houses where a power point has to be adapted from non-grounded (two prong) to grounded (three prong) and there is no ground wire in the outlet to do it with. The most common way is to run a ground wire from the outlet to the nearest cold water pipe (plumbing codes in the US actually require that enough iron or copper be buried so that the pipe can serve as an electrical ground).
* The neutral wire has the same amount of energy running through it as the black wire!
This is only true for a single phase circuit, in dual or triple phase circuits or two or three circuits that share a neutral (because they're on different phases) the current through the neutral wire depends on how much current is being taken up by the different hot branches. It is entirely possible that you have current flowing in one hot wire and out another hot wire and the neutral doesn't pull any current at all. Of course that said, you should always assume (for safety purposes) that the neutral is pulling as much current as the hot because it can.
Windows is a bonfire, Linux is the sun. Linux only looks smaller if you lack perspective.
Since cell phones cause gas stations to explode (according to the label on the pump anyways), this means you shouldn't be using your laptop while pumping gas.
It sounds like in your grandparents house the subpanel is grounded to the piping, not a true, seperate earth ground. That's common in a lot of older or not professionally installed electrical systems and they should have it looked at and repaired by an electrician. I've encountered quite a few older installations like that. It's dangerous because the piping system doesn't make a very good ground.
tic
1) Take child's pet and laptop
2) Charge laptop heavily
3) Put pet on laptop
4) Sue!
In Soviet Russia, laptop overclocks YOU.
1) The ground wire goes to the metal casing of the outlet, not all the way to the grounding bar, to eliminate the possibility of 'floating' voltages or charge buildup along the neutral.
Actually, the ground wire goes to both. It is normally grounded to any ground screws or wires on attached receptacles, switches, light fixtures, etc, plus it is grounded to the casing on any metal boxes it passes through (but not on the plastic boxes that are more and more common these days as it's rather pointless to ground plastic). The ground wire does terminate on the ground or ground/neutral bar in the service panel.
2) The ground wire typically connects directly to the metal case of the device, so that if the hot wire accidentally makes contact with the case inside the device it won't shock the user.This is correct, plus it will also trip the circuit breaker.
3) Although in principle you could get these benefits from hooking up the neutral to the case and doing away with the ground wire, it would have dire consequences if the user reversed the plug. Therefore the ground plug is triangular and not reversible.If the plug is polarized then you could not reverse it without filing down the wide (neutral) prong. That said, there are other reasons to properly ground a metal casing as others have pointed out the neutral can carry a small current and is not suitable as a proper ground, plus faults in the neutral will leave you with a 120 V AC hot casing. Note also that the ground prong on a typical ground plug is longer than the other two prongs. This is on purpose to ensure that the ground is always connected first when plugging an appliance in and disconnected last when unplugging.
But its true that the ground wire is a holdout from those days when we used to have metal cases on everything (remember those metal drills - and the XPS, apparently). If the hot wire touched the case the user would get a shock, hence the ground prong.I would hardly call it a "holdout". There are lots of devices that still require a proper ground and have metal casings a brief list off the top of my head is:
- Major Appliances such as refrigerator, dishwasher, electric ranges and ovens, washing machines, dryers, waste disposal.
- Desktop computers
- Workshop tools such as drill presses, Skill saws, etc.
- Almost all industrial workshop equipment.
Certainly we will not have an end to the requirement for grounding any time in the foreseeable future.Windows is a bonfire, Linux is the sun. Linux only looks smaller if you lack perspective.
I occasionally get zapped by my MacBook, although I'm not sure whether the problem is static electricity or something going on in the lappie itself. The power supply can be run either ungrounded or grounded, and usually my preference is to run grounded. This reminds me: gotta visit a genius sometime soon about this. Oh yeah: it's encased with plastic.
Knowledge is power. Knowledge shared is power multiplied.
To quote a Telstra commercial completely out of context, "this wouldn't happen in Australia!" American plugs only have two prongs, whereas Australian (and plenty of other countries, I'm sure, but I wouldn't know) plugs have three prongs, one of which is earth. Of course, this only benefits us when designers of metal-cased hardware remember we have an earth prong.
Admit it. You post strawman arguments as AC so you get modded Insightful for refuting them, rather than Troll
He's correct. It's a safety issue.
Also, prolonged contact with (nearly) ANY electrical current that you can feel can become dangerous. While a low voltage won't be able to pass much current through the skin (skin resistance) initially, this situation will change. As voltage flows skin resistance slowly decreases, and can lead to fatal currents if allowed to persist for long enough.
Effects of current through the human body (rough):
0.2 amp - no fibrillation. Severe burning and breathing halted.
0.1 - 0.2 amp is the most dangerous zone, because fibrillation is a faster death and harder to stop than a mere stoppage of the heart as occurs above 0.2 amp.
Skin resistance is about 1kohm for wet skin and 500kohm for dry skin. Internal resistance is 100-500 ohms, so current penetrating the skin is what causes problems. Higher voltages let more current through, so above 240V current easily penetrates the skin. If you touch a wire of 0.02 amps or so your muscles will contract, forcing you to hold onto the wire. Since skin resistance drops over time you will soon find it difficult to breathe and eventually you WILL die.
If you find someone stuck to a wire in this manner, the person WILL die if they are not removed. Do not attempt to touch them uninsulated, since you will likely become stuck yourself. Turn power off, or push them off with a stick or other non-conductive object.
Not a sentence!
I for one am shocked by this red-hot story. This is no way to conduct electri- I mean business.
"Teach a man to build a fire, and he's warm for a day. Set a man on fire and he's warm for the rest of his life."
Well, don't take the AC adapter with you when offering it for repair. We are modifying the laptop, just the ground-less power cord.
Windows has detected an undetectable error.
When you have a grounded metal casing, and most electronics should be grounded for safety, you will always get half of the current to your case if you either don't have a grounded power outlet or there is a problem with it. It's only dangerous if there is a serious electric problem, you touch your metallic electronic non-grounded but expecting grounded device and some grounded source such as your sink.
Optionally to make sure that it hurts, you can also stand in a puddle of water.
Lots of laptops have this problem. My Macbook Pro has it, and I know of some friends with plastic laptops that have it too.
Disclaimer: I'm assuming everyone here knows what they are doing. Mains power can be very hazardous and very deadly. Do NOT attempt this if you are unsure of what you are doing -- call someone more experienced if in doubt. But for those of you who know what you are doing, this should be an easy fix to avoid the shock of you being used for a ground wire.
Disclaimer Addendum:
Slashdot can in no way be held liable for the failure to disconnect the power cord during the above mentioned procedure
I've had this happen to me a few times with my Macbook Pro (or was it just with my previous Powerbook G4?) You ground yourself somehow -- say putting my bare foot against a metal chair or desk leg, and suddenly I get a slightly painful buzz from the seam between the wristrests and edge. I guess that's where there is a sliver of bare aluminum between the end of the adonized metal and the plastic rim. Always annoyed the hell out of me, but not consistently reproducible so I never got it fixed.
Metal casing... ungrounded power... what does one expect?
I remember the worst shock I ever got was performing at a club. I leaned in to sing with an old metal grill microphone plugged into a shoddy amp. I got a terrifically painful zap to my lower lip and I jumped back. The lights in the room flickered for a moment... or so I thought. Nobody else saw the flicker, so I guess it was that the shock knocked out my vision for a split second. Yeesh.
I have an SZ1 and an SZ4 (later model) which are carbon and darkened brushed alu - both do it, but not all the time. The PSU, however, is properly earthed..
Insert
To get the fix for this you have to install a patch that activates a little mechanical leg that kicks you in the beanbag.
Seriously people, stop buying Dell's crap.
I predict the results of a soon-to-be-released study: Laptop usage has positive effects on rheumathism.
What a depressingly stupid machine.
So glad after all these years I have finally got proof I was not imagining things! Until this slashdot posting, I had assumed I was alone. Phew! I owned a 12" PowerBook and had to sell it because every time I used it, the skin on my fingers would crack - and after extended use, bleed at the cracks - despite my good health. Same if I used a relatives 15" aluminium PowerBook for more than a few minutes. I always felt some minor tingling, even in my older (2001) Titanium PowerBook, but only in certain circumstances that must be related to the power adapter issue. What is worrying is that the new MacBook Air is aluminium and I would like to buy one later in the year to replace my aging MacBook that causes no problems being plastic. So, it would seem that the electrical leakage is slightly burning my skin? Or am I allergic to aluminium?
O'WONDERWe're working on it.
FYI My ASUS A6VA has a similar issue - it jolts me whenever I touch the media control buttons (that just happen to be brushed aluminium) while I'm grounded.
It's not exactly a mains strength jolt, but uncomfortable nonetheless - I just never really thought of complaining about it until now.
I suspect it's a design flaw - the machine boasts the ability to play CDs without turning it on - so somewhere around that media circuit there must be power, and it just happens to reach the buttons =/
I have spoken'eth.
I have worked for three years for a cellphone charger manufacturer and designed a few battery chargers. Almost all of the chargers are Class II devices. Several the cellphone manufacturers specifically stated in their specifications that the use of the so called Y capacitors was not allowed because some phone models had metal housings. A Y capacitor is a safety capacitor put across the SMPS transformer, between primary and secondary. It is used for EMI reduction. The problem is that it creates a path between the primary side (AC mains) and the secondary side (load, in this case the cellphone), and the resulting leakage current is high enough for the cellphone user to feel an uncomfortable tingle while holding a phone connected to the charger. All notebook power supplies that I have disassembled are Class I devices, and all have Y capacitors. Moreover, they have an electrical connection between the protective earth prong on the AC inlet and the DC ground (-) on the output. In that case, if the AC socket is properly grounded, the leakage current through the Y capacitor is diverted to earth and the user feels no tingle. On the other hand, if the protective earth of the SMPS is disabled or not properly connected, it behaves just like a Class II device equipped with a Y capacitor, and the notebook user will feel the tingle.
WTF?
Umm.. it's "Grounded". Not "Earthed" ya dweebs. What, did you think you were being clever or something? "Earthed" isn't even technically correct, like Sun vs Sol. It's just plain wrong, and doesn't even SOUND smart. Geez.
Official Heretic from the "Church of Global Warming". Proven right thanks to whistle blowers. AGW = Flat Earth Theory
Strangely, Apple has been shipping "conductive" laptops for some time, none of which have exhibited this sort of effect.
WhiteWolf666 an exBush supporter. All you new-school,compassionate,save the children Republicans can rot in hell
I bought a relatively new Xbox 360 and it also has a 2-prong adapter on the power brick and power cable. Could this be part of the problem people have with the Ring of Death? Why on earth is the system not grounded?
what connection were you using on the power supply? the 2 pin snap-in plug or the 3 pin cable?
I personally have never noticed this issue with the Titanium or the Aluminum Powerbooks using either connection.
maybe you are just allergic to Apple?
the history of the world
I hear a lot of tingling fingers. If this is current, there must be another body part tingling. Where is the current leaving the body???
If there is no seperate tingle, then people are just feeling heat or some other source of vibration, but its not electricity.
I've got a 7 year old Dell Inspiron 4100 that likes to shock me on occasion. Usually it happens when handling the laptop from the right side where the Ethernet port resides. I think it's the same problem, but that's about the only place where metal is readily present from the shielding around the port. ... I must say that it's a pretty good size zap when it does decide to bite me. It's well above any normal static discharge.
That's it Michael, you're grounded!
Media that can be recorded and distributed can be recorded and distributed.
-kfg
My oldish vaio does this - there are some parts on the front where the plastic has worn away, leaving metal exposed. This, combined with the two-prong charger can produce some interesting surprises depending on what else I happen to be touching at the time. I'm just glad I don't surf in the nude, on my lap....
-- All your booze are belong to us.
I'll never buy one of their laptops again. I had an Inspiron 5150 (gave it to my dad, does that make me a bad son?) and it runs hotter than hell. My dad bought one of those USB fan arrays to sit it on. It takes away from its battery life and the ideal purpose of mobility.
One little glitch I've seen in a number of Dell laptops is false hard disk failures at boot. Troubleshooting this on the Inspiron, I got irritated and tried a primitive yet tried and true method to fix it: percussive readjustment. Banged on it. More of a thump with my index finger. It worked. I met a guy sometime later with a brand new XPS laptop he had owned less than two weeks that gave him the same problem. I told him my solution, he tried it and it worked!
Chewbacon
The Bible is like Wikipedia: written by a bunch of people and verifiable by questionable sources.
It sounds like in your grandparents house the subpanel is grounded to the piping, not a true, seperate earth ground. That's common in a lot of older or not professionally installed electrical systems and they should have it looked at and repaired by an electrician. I've encountered quite a few older installations like that. It's dangerous because the piping system doesn't make a very good ground.
tic
I would agree, except that the house is new (built in 2001) and was all done by licensed contractors. I'm quite confident something is getting grounded to the pipes, but I'm not sure what. Could it perhaps be something like the well water pump or water heater? I'm also still not sure what was with that coaxial cable either (although I honestly do not remember where I was when I found that cable). I'm guessing it was actually grounded, probably to an outlet, but somewhere else part of the socket grounding wire must have come undone, resulting an any ground leaks being routed to the coaxial cable. (For what it is worth, the coaxial cable was disconnected on the end I touched.)
Stylish sheet to fix many problems in Slashdot's D3: https://gist.github.com/801524
'Round here we fire folks who keep touching their laptops in meetings.
Dell's chief blogger just revisited the "tingling" experience with a post over at Direct2Dell. http://direct2dell.com/one2one/archive/2008/01/18/41538.aspx
Interesting. It's very possible it's the water heater or pump, although those should be easy to check. The best way I'm aware of to find out would be to check the resistance across the various systems to the piping; this can be done with a VOM and ground strap. Anything under a megaohm or so I'd consider suspect. Best bet is to get a qualified electrician to check the system; having the original contractors there to pinpoint where the wiring was run wouldn't hurt either. I'm NOT a qualified electrician, just a basic maintenance grunt (albeit a very experienced one) so go get one. There are many possibilities, and even professional installers make mistakes.
:(
An anecdote: I remember one newer apartment I worked on not long ago where I got a mild shock off of the toilet supply valve when I went to change it out; turned out that a sheetrocker had driven a screw thru the wiring at a point where the screw also contacted the copper piping behind the wall (no wiring shield was installed there for some reason, and space was so tight the piping was run almost directly behind the wiring channel). Figuring out where that was happening took the better part of a day and the tearout of a large amount of sheetrock.
Fortunately the screw had only contacted the neutral and not the hot wire (and even then the contact was very intermittent), otherwise I might have gotten badly burned - the valve had almost completely failed and I was kneeling in a shallow pool of water. Upon questioning the prior (and first) occupants of the apartment, turns out they'd had intermittent electrical problems on that circuit that they'd never reported to the landlord, specifically the bathroom GFCI would trip at odd times even when there was nothing plugged into it. Shit happens...
The coax I can't help you with other than to suggest that, barring any direct accidental connection to the electrical wiring, it's possible that the coax insulation is broken somewhere (house entry?) where it's making contact with the electrical ground that's carrying current. That's a weird one, I'm surprised the cable installers didn't notice stray currents on the coax.
Good luck!
tic
I'm a little late to the party, but I thought I'd add some information. This "feature" is nothing new among Dell laptops; I have an Inspiron E1705 that does the same thing (which also manifests itself as stray voltage on the chassis) when used with the supplied 90W, 2-prong adapter. When used with the 130W, 3-prong adapter from the Precision M90 (which I also have), any stray voltage on the chassis is gone.
Dell's position has been--and continues to be, it seems--that this condition is "normal" and occurs in a number of other laptops (which is true) and other consumer products. But I find that position remarkably non-reassuring, and the fact that the stray voltage continues to be a feature of new Dell laptops suggests that Dell isn't too concerned about fixing the problem.
For what it's worth, the (90W) adapters don't seem to have a very long service life--two of mine have fried themselves within the first year of use.
I hear a lot of tingling fingers. If this is current, there must be another body part tingling. Where is the current leaving the body???
If there is no seperate tingle, then people are just feeling heat or some other source of vibration, but its not electricity.
You are right about one thing, there must be an entrance and an exit, so to speak, for a complete circuit to be made through your body.
What you may not be considering is that some parts of your body are more sensitive than others (I hope you are aware of that, or you're missing out on some real fun stuff). Also, I've noticed this buzzing sensation only when my hand is lightly touching the electrified object in question - if I press my hand against it strongly, the sensation isn't there. So, I think it's because your feet (or other body parts) are pressed firmly to the floor and aren't experiencing the same sensation, even though a tiny amount of current is flowing.
Putting moderation advice in your