After a User Dies, Apple Warns Against Counterfeit Chargers 457
After a Chinese woman was earlier this month evidently electrocuted while talking on her iPhone while it was plugged in to charge, Apple is warning users to avoid counterfeit chargers. From CNet:
"Last week, reports surfaced in China that suggested the woman, Ma Ailun, might have been using a third-party charger designed to look like the real thing. Although third-party chargers are not uncommon, they vary widely in terms of safety and quality.
Earlier this year, safety consulting and certification company UL issued a warning that counterfeit Apple USB chargers were making the rounds and that consumers should be on the lookout for them due to their lower quality and possibly dangerous defects. The company posted the guidance on its site after a woman was allegedly electrocuted while answering a call on her iPhone."
Re:Huh. (Score:5, Informative)
http://www.belkin.com/us/Device/iPhone/d/IPHONE?q=::categoryPath:/Web/WSPWR [belkin.com]
Apple is asking people not to buy counterfeit or unauthorized ones that don't meet the specs.
Re:Not buying it (Score:3, Informative)
Those wires can easily carry 1A which at 220V is more than enough to kill you. The exposed metal bits of a device are often connected to a shield ground, and if that "ground" is actually at 220V line potential then it would be easy to kill someone.
Re:Not buying it (Score:5, Informative)
No one is being killed by the 5v on the USB bus. The problem is the counterfeit chargers are often poorly designed and can fail in a way that shorts the USB cable to the AC power.
There was an excellent teardown & analysis [righto.com] of a cheap charger last year that pointed out serious safety issues.
Re:Huh. (Score:5, Informative)
I think something was lost in translation. It's not the third-party chargers that we would normally buy, it's the ultra cheap inferiorly made chargers that pass themselves off as an Apple product that is the problem.
The best advice for any country and any make of phone is that when looking for a replacement charger that plugs into your home's AC be sure to choose a charger that is certified for safety (e.g. UL, CE, MEPS, RCM, C-Tick. I guess the closest Chinese equivalent are CCC, CCIB, CCEE).
Re:Not buying it (Score:5, Informative)
Take a look at a teardown of a fake charger [youtube.com] and you'll understand why it can be lethal. The creepage distances in particular are atrocious.
Re:How? (Score:5, Informative)
No one is going to die by having 5volts applied to their face.
But they do die from having 220 volts applied to their face.
The issue is that the counterfeit chargers short and deliver the mains directly to the head. It doesn't matter what electronic device is involved. hell, doesn't matter if any electronic device is connected to the end of the other side of the USB cable when the circuit is completed.
It isn't 5v, it's 340v! (Score:4, Informative)
See the commentary at the top of the page from this link:
http://www.righto.com/2012/03/inside-cheap-phone-charger-and-why-you.html [righto.com]
--Paul
Re:Not buying it (Score:4, Informative)
I'm not buying it, how could you possibly screwup a USB charger to the point where it would be lethal? I mean the cables aren't generally thick enough to carry enough 220V current to kill someone before they melt and 5.5V DC certainly isn't going to kill someone.
It only takes 100mA - 200mA [ohio-state.edu] of current to kill someone, and every USB cable is designed to carry at least 500mA since the USB spec says that USB hosts can supply up to 500mA of current (and many plug-in chargers exceed that). So it's certainly feasible that a USB cable can carry enough current to kill someone. It's not the voltage the determines the size of the conductor, it's the current.
The USB cable wires may not have sufficient insulation to protect against 220VAC (peak voltage is higher, around 310V if I remember correctly), but that's the point -- 220VAC is not supposed to be supplied to a USB device. But even if it's not certified for the voltage it seems that the individual conductor insulation combined with the plastic outer sleeve of the USB cable would seem to provide at least enough isolation, I think most plastics used for insulation have around 500 - 1000V/mil (1/1000th of an inch) of breakdown voltage.
I'm surprised that a phone doesn't have at least 220VAC of isolation between the USB power and the phone case. Is this typical in phones?
Re:Smart move (Score:5, Informative)
Nope.
Both iPhones and Apples come with a little AC->USB charging brick and a cable. The difference with most Android phones is that the cable is a standard USB cable, not a 30-pin or lightning cable. But the brick is the dangerous part.
Ken Shirriff did a couple excellent tear downs last year comparing the build of the Apple charger [righto.com] vs a cheap knockoff [righto.com].
You can have this exact same problem using a cheap knockoff with an Android phone so be careful!
Re:Smart move (Score:5, Informative)
It's the "big lie". What is the charger for an Android phone? Oh right, a standard USB cable. What is the charger for an Apple product?
The Apple charger has a standard USB power port. Just like all Android chargers that plug into a power outlet.
Here is Apple's standard USB charger [amazon.com]. Note that it has a USB port.
Here is a Galaxy S4 USB charger [emirates247.com]. Not that is has a USB port.
Either charger can be used interchangeably to charge either phone.
Re:Smart move (Score:0, Informative)
Just for fun: Nobody, not even a single person or even animal, has ever been electrocuted and survived in any situation, ever.
Re:Smart move (Score:1, Informative)
I call bullshit on this. I have a Rio Carbon which was released in 2004 which uses a USB charger as standard.
Re:Smart move (Score:4, Informative)
It became an officially mandated standard in the EU for cell phones in 2010.
Re:Smart move (Score:2, Informative)
These are switchmode supplies, not linear.... (Score:5, Informative)
, and they contain a bit more than a simple transformer and regulator.
They take the AC line voltage, rectify it to high voltage DC, chop the DC up into high frequency pulses with a MOSFET, step the pulsed voltage down with a specially designed transformer, then rectify the output to low voltage DC. A sample of the output DC is then fed back to the primary side circuitry to achieve closed loop regulation.
Because the primary side of the system is at line potential, the insulation in the switching transformer (and the optocoupler used in the feedback loop) is all that prevents the output side from presenting a shock hazard with respect to earth ground. The quality of construction of many of the Chinese knockoff chargers is downright terrible, and I could easily believe that an insulation breakdown. Dave Jones "EEVBlog" did a teardown of one of these a while back. Scary stuff if you know what you are looking at:
http://www.youtube.com/watch?v=wi-b9k-0KfE [youtube.com]