USB ports that cause electric shocks when plugging in flash drive

[Arvo]

I occasionally plug my USB flash drive into a computer at a cybercafe,
and notice that the metal parts of the flash drive give me a shock (a
small, low voltage shock but a shock nevertheless.)

At other cybercafes, I don't have this problem. Just at some.

Can this damage my flash drive? What is wrong with the computer that
causes it to do this?

So far my drive is still working after suffering a number of these
incidents. Also, I have continued using the drive when it was plugged
into one of these rogue USB ports, and it still functioned.

Thanks for any insight.

 

[Ted Zieglar]

My guess is static electricity. Perhaps the cyber cafes that shock you
have thick carpets, or something else that builds up a static charge on
your body. Ground yourself before you handle your flash drive...which
may give you a small shock just the same but at least your flash drive
won't take the hit.

I am not knowledgeable enough to know if a static charge will damage
your flash drive, but I'll bet it's not doing the drive any great favors.

 

[Malke]

My guess is static electricity. Perhaps the cyber cafes that shock you
have thick carpets, or something else that builds up a static charge on
your body. Ground yourself before you handle your flash drive...which
may give you a small shock just the same but at least your flash drive
won't take the hit.

I am not knowledgeable enough to know if a static charge will damage
your flash drive, but I'll bet it's not doing the drive any great favors.

The OP has been lucky. The slight static shock that we humans feel is enough
to destroy computer components. If the drive doesn't produce shocks
anywhere else, then you know the issue is being caused by static
electricity at the cyber cafe(s). As Ted Zieglar said, maybe the cafe has
thick carpet. If the shock happens elsewhere, replace the usb key because
sooner or later it's going to fail.

Malke

 

[Arvo]

No Ted, that's not it. These cybercafes are in SE Asia, and I've yet to
see one with carpeting on the floor. Also, the shock is not just a
split second thing and then it's over. I'm talking about a tingle of
electricity that continues on the metal parts of the flash drive as
long as it is plugged in.

 

[Ted Zieglar]

You've got me there. I don't know anything about construction or
electrical codes in Southeast Asia. But Like Malke wrote, it's not good
for the flash drive, so stay away from those places.

 

[Sylvain Lafontaine]

Then in this case, I would be more concerned about your own health and the
clear possibility of suffering a real electrical accident in the future then
I would be for the USB key to suffer damages.

The electrical wiring for this computer or the cybercafe seems to be at
fault here.

 

[JohnO]

The electrical wiring for this computer or the cybercafe seems to be at

fault here.

That's very likely the problem. Without testing, I'd guess their ground is
reversed with either the hot or neutral, either the cord supplying the PC or
the building wiring itself.

Two things...First, someone could die in this cafe if their body makes a
good connection to a real ground somewhere. This is a serious problem.

Two, don't go there anymore. If you must, *make sure* you don't touch any
grounds while touching the computer, and regardless what you do make sure
the person in charge of the place is aware of this problem.

-John O

 

[JS]

Bad electrical ground path, it's a wonder you don't get shocked when
touching the PC, even when not using/connecting the flash drive.

JS

 

[Jim Macklin]

Also, the cafe has poor wiring and their computers are not
properly grounded, probably they have used two wire plugs or
even cut the grounding plug.


Anyway, touch the computer before inserting any device
should equalize charge potential before it spikes the
device.


| Ted Zieglar wrote:
|
| > My guess is static electricity. Perhaps the cyber cafes
that shock you
| > have thick carpets, or something else that builds up a
static charge on
| > your body. Ground yourself before you handle your flash
drive...which
| > may give you a small shock just the same but at least
your flash drive
| > won't take the hit.
| >
| > I am not knowledgeable enough to know if a static charge
will damage
| > your flash drive, but I'll bet it's not doing the drive
any great favors.
|
| > Arvo wrote:
| >> I occasionally plug my USB flash drive into a computer
at a cybercafe,
| >> and notice that the metal parts of the flash drive give
me a shock (a
| >> small, low voltage shock but a shock nevertheless.)
| >>
| >> At other cybercafes, I don't have this problem. Just at
some.
| >>
| >> Can this damage my flash drive? What is wrong with the
computer that
| >> causes it to do this?
| >>
| >> So far my drive is still working after suffering a
number of these
| >> incidents. Also, I have continued using the drive when
it was plugged
| >> into one of these rogue USB ports, and it still
functioned.
|
| The OP has been lucky. The slight static shock that we
humans feel is enough
| to destroy computer components. If the drive doesn't
produce shocks
| anywhere else, then you know the issue is being caused by
static
| electricity at the cyber cafe(s). As Ted Zieglar said,
maybe the cafe has
| thick carpet. If the shock happens elsewhere, replace the
usb key because
| sooner or later it's going to fail.
|
| Malke
| --
| MS-MVP Windows Shell/User
| Elephant Boy Computers
| www.elephantboycomputers.com
| "Don't Panic"

 

[JohnO]

If you're getting a continuous shock from the PC's chassis, touching that
chassis is the LAST thing you want to do. You will not equalize the charge,
you will become a load on a circuit that can deliver 10/20 amps of
120/220VAC current, no joking matter.

Static discharge is a different beast, it's harmless to humans. A hot
chassis is a potential killer.

-John O

 

[Loren Pechtel]

Two, don't go there anymore. If you must, *make sure* you don't touch any
grounds while touching the computer, and regardless what you do make sure
the person in charge of the place is aware of this problem.

Playing with hot wires is a matter of life and death. I seriously
doubt that using the cafe is a matter of life and death. Don't go
there until it's fixed, period.

 

[Loren Pechtel]

No Ted, that's not it. These cybercafes are in SE Asia, and I've yet to
see one with carpeting on the floor. Also, the shock is not just a
split second thing and then it's over. I'm talking about a tingle of
electricity that continues on the metal parts of the flash drive as
long as it is plugged in.

Then you've got a major electrical problem in the cafe. I wouldn't
touch anything metallic there--you're probably dealing with line
voltage. Dry hands and you're *PROBABLY* safe but it's not something
you take chances with. Come a rainy day and it might be the last
thing you ever touch.

 

[Arvo]

Thanks for the replies. Well, these particular computers are actually
in a "mini hotel" in Vietnam. Mini hotels often have computers for the
use of their guests here. I've no doubt the wiring is all wrong,
ungrounded, or whatever, as there are no standards here and people
don't understand the need for proper grounding. But I have touched the
computer case many times and there is no shock there. It's only from
the USB port. And please note, it's a mild electrical tingle that I
feel on the metal parts of the flash drive, not really a "shock."

I have also had this problem at some cybercafes in Thailand.

My flash drive still works, maybe its life has been shortened, but
fortunately they're getting cheaper and cheaper. But I will avoid all
such computers in the future.

 

[Loren Pechtel]

Thanks for the replies. Well, these particular computers are actually
in a "mini hotel" in Vietnam. Mini hotels often have computers for the
use of their guests here. I've no doubt the wiring is all wrong,
ungrounded, or whatever, as there are no standards here and people
don't understand the need for proper grounding. But I have touched the
computer case many times and there is no shock there. It's only from
the USB port. And please note, it's a mild electrical tingle that I
feel on the metal parts of the flash drive, not really a "shock."

I have also had this problem at some cybercafes in Thailand.

My flash drive still works, maybe its life has been shortened, but
fortunately they're getting cheaper and cheaper. But I will avoid all
such computers in the future.

If your hands are dry you probably only get a mild tingle. I've
touched hot stuff twice in my life. In one case it was a fairly
strong tingle but I had been struggling to plug the stupid thing into
an awkward spot and so I'm sure my hands were a little bit sweaty.

The second time there was an unknown but probably fairly high
resistance in the circut as the contact was through burned food. That
gave a very mild tingle.

 

[JohnO]

And please note, it's a mild electrical tingle that I

feel on the metal parts of the flash drive, not really a "shock."

All that means is that the resistance of your fingers is high. With a sweaty
finger, or touching at a cut or even freshly healed skin, the resistance
decreases and the current increases and that mild tingle can turn into
something much more serious.

If you measure that voltage, it's 120 VAC or 240, whatever they use in
Vietnam.

Anyway, be careful.

-John O