USB Charger electrocution

Hi All,

No doubt you have all read or heard about this recent story;

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It seems to me a lot of double-insulation has to fail, in both the USB-Charger and in the laptop headphones and laptop charger, to produce the electrocution, which seems rather improbable to me.

I'm not doubting the fact of the electrocution, just the alleged method. No one has mentioned a nearby lightning strike, but that seems more likely than the proposed mechanism.

Or am I missing something obvious?

Ross

Reply to
RMD
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I agree. I was not aware of a lightning strike though. When I first heard of it I imagined headphones connected to a grounded class 1 system and a fault in the class 2 USB charger.

Tony

Reply to
Tony

"RMD"

** The only device that has been claimed to be faulty is the USB charger used with the phone. Most laptops are earthed to the AC safety ground when charging, which seems the only way the victim could have completed a circuit to ground if she had hold of some metal part of it.
** Yep - my first thought was that the alleged burn injuries were more likely from lightning.
** Wait for the Coroner's report - cos that will contain actual facts.

... Phil

Reply to
Phil Allison

What double insulation?

Reply to
news13

You left the class 3 police and class 4 journalists out of the equation - there's a lot of stupidity in this world, and it seems to be concentrated among those who're supposedly credible :-(

I know of precisely zero laptops which can be charged from a USB charger - they all need in excess of 15V (even "netbooks" need at least 12V) at several amps, whereas even the most powerful USB chargers can barely muster

2A and never above 5V.

If the "USB charger" was in fact a device which plugged into her laptop's USB port and provided power to yet another device, how the f*** did she manage to get electrocuted by 5VDC?

Based on what I've seen on assorted web sites, I'm more inclined to think that she was having a bath with her laptop by her side, likely on webcam with someone, when the laptop and charger both fell into the tub.

--
Bob Milutinovic 
Cognicom
Reply to
Bob Milutinovic

In a properly designed and constructed charger, that's true.

Some of the USB chargers that can be bought from China are not properly designed, and electrocution is not especially unlikely.

Sylvia.

Reply to
Sylvia Else

** You being funny or you have no idea what "double insulation" means ?

... Phil

Reply to
Phil Allison

My understanding was that they didn't meet Aussie standard and thus were not double insulated.

Reply to
news13

** So Australia has the only "double insulated" electrical appliances in the world ?

FYI:

Australian electrical standards are closely derived from similar IEC standards.

Almost every country in the world is a member (or affiliate) of the IEC - including China.

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If a manufacturer builds an item to meet double insulation requirements, they can use the double square symbol - no outside certification is required for that.

However, items like USB chargers fall into special category (called prescribed items) where agency certification and labelling to the relevant Australian standard is legally essential in order to go on sale here.

For items made in China, such certification can be done by locally and is normally little more than a formality - assuming that the design meets international standards.

.... Phil

Reply to
Phil Allison

Double insulated means just what it says. The low voltage side must be separated from the high voltage side by two insulators, each of which is, on its own, capable of resisting the mains voltage.

Sylvia.

Reply to
Sylvia Else

** Fraid that is not the case in reality.
** However the rules for class II appliances are not so pedantic.

A single layer of a specified material and thickness may be sufficient as long as it is not subject to deterioration in use, or a gap on a PCB between live conductors and user accessible metal few mm wide, or the live and accessible metal parts are bridged only by a class Y capacitor of approved design and low enough value.

Double Insulation sounded like a brilliant idea once - but has been gradually whittled down and compromised in so many ways that it is now real worry considering you have to trust notoriously dodgy Chinese manufacturing culture to get it right all the time, or you could die.

.... Phil

Reply to
Phil Allison

Sounds very similar to this one year old news.

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Reply to
asdf

It makes me wonder how many electric shocks, burned out chargers and fires have actually happened and never been reported. It's only the extreme cases that make the headlines. If you get shocked by a device you are using every day, wouldn't you report it to consumer protection (1300 30 40 54) ?

Funny how this thread got killed and another one opened.

Tony

Reply to
Tony

A youtube video exists that determines that the high voltage side of one of these cheap Chinese chargers is isolated from the low voltage side by a thickness of .25mm between two soldered joints.

That is clearly not just a case of dodgey manufacturing, but really bad engineering in the first place.

I've got one of those $1 chargers mentioned before headed my way, not for use obviously, but for inspection.

Reply to
Clocky

Got two of those, one physically blew the usb plug clean out of the socket when I was not looking. [IMG]

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Reply to
F Murtz

That's nasty and you're lucky you weren't hanging onto it, or the phone. Don't use the other one, rip it apart and see how close the mains input is to the output.

Unfortunately it's not only chargers that end up burning. I bought one of those little wireless keyboards that come with a USB dongle.

I used it for months without issue, then one day I was using it and the keyboard suddenly stopped working. I thought the keyboard needed charging, but then I noticed a burning plastic smell.

It was the dongle, it was so hot that it had turned it's housing into a Dali.

Lucky there was no permanent damage to the PC.

Reply to
Clocky

** If that is the video by Dave Jones, then it is irrelevant to my point.
** It is clearly a case of criminal fraud by the Chinese makers and the HK based dealers on ebay etc.

Got nothing to do with the millions of supplies that come with new equipment and are sold by regular importers.

** Cheap thrills - eh ?

.... Phil

Reply to
Phil Allison

It's not the video by Dave Jones which I have also seen. He too noticed the poor isolation between mains and output IIRC so it's relevant to my point.

I don't think they deliberately set out to kill people, but clearly poor design and manufacture is having that effect.

Nobody said it did.

Not as cheap as one of your rants ;-)

Reply to
Clocky

** Shame your point has nothing to do with the para you posted under.

** Nobody said they did - fraud is not connected to murder.

So another total irrelevance.

** By posting your drivel where you did, you made that implication.

With any luck, your $1 Chink time bomb will kill you.

.... Phil

Reply to
Phil Allison

I said they didn't, nobody said they did.

fraud is not connected to murder.

I didn't say it was, and it wouldn't be murder in any case.

Much like most of your posts.

I certainly did not, you just made your usual assumptions based in your incomprehension.

Unlike you Phil, I know what I'm doing.

Reply to
Clocky

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