Holy Fuk, USB probably killed a person. Wiii To Stopud

On 7/20/2013 12:48 PM, Chris S. wrote:

"
"I have seen blue electricity arcs jump
over about 1 centimeter, maybe even more."

At what voltage? Or do you have any idea?
"

European union/Netherlands, so probably 220 volts.

Bye,
Skybuck.

Then no, you haven't....

I wouldn't say it was impossible. The arcing is a function of the
surface material. So depending on what is *on* the surface of a PCB
arcing can happen at lower voltages than just an air spark. But yes, it
would need to be something pretty unlikely, perhaps a graphite pencil
trace?

--

Rick

On 7/19/2013 2:21 PM, Michael Black wrote:
On Fri, 19 Jul 2013, Chris S. wrote:


"Skybuck Flying" wrote in message
b.home.nl...

After my DreamPC was killed by USB

And that would be when you foolishly plugged the front panel USB cable
into the MB
header incorrectly? Or has memory failed me?
You've made and kept a map of his postings?

I barely know Starbuckflying, but I remember that! He ranted on and on
about how PCs were crap because he wasn't prevented from screwing it up.
He caught no end of crap from the folks here because of it. He was
greeted by the welcome wagon you might say...

--

Rick

On Sat, 20 Jul 2013 15:32:01 -0400, the renowned rickman
wrote:

On 7/20/2013 12:48 PM, Chris S. wrote:

"
"I have seen blue electricity arcs jump
over about 1 centimeter, maybe even more."

At what voltage? Or do you have any idea?
"

European union/Netherlands, so probably 220 volts.

Bye,
Skybuck.

Then no, you haven't....

I wouldn't say it was impossible. The arcing is a function of the
surface material. So depending on what is *on* the surface of a PCB
arcing can happen at lower voltages than just an air spark. But yes, it
would need to be something pretty unlikely, perhaps a graphite pencil
trace?

Starting an arc at 220V @STP requires something pretty close to
contact ( 10um). It can be maintained over quite a distance with
something like your carbon electrodes if they get hot enough to free
up some electrons. 10mm is not a problem. Test the interrupting
capacity of a 5x20mm glass fuse and you'll see.



Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

"rickman" wrote in message
...
On 7/20/2013 12:48 PM, Chris S. wrote:

"
"I have seen blue electricity arcs jump
over about 1 centimeter, maybe even more."

At what voltage? Or do you have any idea?
"

European union/Netherlands, so probably 220 volts.

Bye,
Skybuck.

Then no, you haven't....

I wouldn't say it was impossible. The arcing is a function of the surface
material. So depending on what is *on* the surface of a PCB arcing can
happen at lower voltages than just an air spark. But yes, it would need
to be something pretty unlikely, perhaps a graphite pencil trace?

--

Rick

Pashen's Law suggests that to arc 1 cm The voltage (potential)
would need to be ~3 KV, in air, at STP. Skybuck was unable to describe
what the arc conditions were. In that he said "jump", I assumed he meant
in air.

Chris

On Sat, 20 Jul 2013 12:32:16 -0400, "Chris S."
wrote:

"I have seen blue electricity arcs jump
over about 1 centimeter, maybe even more."

At what voltage? Or do you have any idea?

Quite possible during a thunderstorm.
In the old days in rural areas with open wire power lines at the end
of the line, flashovers could occur between the holes in mains socket.
You had to keep the curtains away from the sockets during
thunderstorms.

IIRC in Europe, the test voltage for ordinary devices is 1500 V and
for equipment to be installed in the main distribution panel the test
voltage is at least 2.5 kV.

For dry air, the breakdown voltage is about 1 kV/mm and allowing for
moisture and dirt, the distance should be considerable larger. How to
fit such distances in to the miniature enclosures of today, is quite
hard. Some potting materials might help, but how can you be sure that
there are not air pockets below the potting material.

On Sat, 20 Jul 2013 13:07:20 -0400, Spehro Pefhany
wrote:

On Sat, 20 Jul 2013 00:45:47 -0500, the renowned Robert Wessel
wrote:


Or is the idea that someone slapped an Apple label on a (bad) generic
adapter?

You can buy Apple-look-alike (on the outside) adapters with or without
Apple-like markings, down to the Apple logo and "Designed in
California" and green dot.

Where do you expect that the Apple (or some other well known brand)
adapters are made ? Most likely in China.

There are cases, in which the factory, during the day shift, makes
some electronics modules for the foreign customer, when their
inspector is present. During the night shift, with no foreign
inspectors present, the same product, perhaps with a different label
or possibly using cheaper components are made and sold directly to end
users.

On Sun, 21 Jul 2013 10:33:26 +0300, the renowned
wrote:

On Sat, 20 Jul 2013 13:07:20 -0400, Spehro Pefhany
wrote:

On Sat, 20 Jul 2013 00:45:47 -0500, the renowned Robert Wessel
wrote:


Or is the idea that someone slapped an Apple label on a (bad) generic
adapter?

You can buy Apple-look-alike (on the outside) adapters with or without
Apple-like markings, down to the Apple logo and "Designed in
California" and green dot.

Where do you expect that the Apple (or some other well known brand)
adapters are made ? Most likely in China.

They're almost all made in China. And? It's a big country.

There are cases, in which the factory, during the day shift, makes
some electronics modules for the foreign customer, when their
inspector is present. During the night shift, with no foreign
inspectors present, the same product, perhaps with a different label
or possibly using cheaper components are made and sold directly to end
users.

Yeah, I know China. That's not what's going on here. The designs are
totally different, the PCBs are different, the moldings are different,
and the components are different.


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com