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fly4grins(at)gmail.com
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 Posted: Wed Jun 25, 2014 6:19 am Post subject: iPod shocks |
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| Quote: | | Hi Guys- Â it sounds like you are getting a half wave tickle, which could imply that the guts of the device are intended for a polarized plug while the polarized plug itself is absent. Â If that is the case, each time you plug in you would have a 50 / 50 chance of getting a have wave zap, 60v here and 110 v for Etienne. Â I'd repeat the V measurement excercise twice, once with each plug / recceptacle orientation. Â If you get 1/2 line V one way and zero the other, there you go. |
Â
[quote]Â
Time: 10:51:06 PM PST US
From: Dave Saylor <dave.saylor.aircrafters(at)gmail.com (dave.saylor.aircrafters(at)gmail.com)>
Subject: How is it I get a shock from an iPod?
Here's a non-aviation question for the group. Â Unless you fly with an iPod,
I guess.
Background:
My son complained today that he got shocked by an iPod. Â FWIW, it's a 5th
gen nano plugged into an Apple USB charging cube by an Apple charging
cord--not knock-off parts. Â First I said yeah, right...but he insisted so
like an idiot I figured I'd show him how that was impossible....and of
course I got shocked too. Â Not as strong as 120VAC but enough to get my
attention.
We were both barefoot (key, I think...) on a concrete slab, in the garage.
 It happened when either of us touched the metal lock switch.  I've never
had any issues with the power strip we were using.
Putting a meter between the lock switch and ground I measure an
invigorating 60VAC. Â Between the neutral of the power strip to any other
ground is zero, so I figure the power strip is wired correctly. Inverting
the cube (it's not polarized) makes no difference, still 60VAC.
I tried a few things: different plug, no shock. Â Different cord, no shock.
 Different cube, no shock.  I went back to the original combination:
 BZZZZT.  So it is repeatable.
There's an Apple support document describing the possibility of static
shock when using their device. Â This was not your typical
feet-on-carpet-touch-a-doorknob static shock. It was sustained as long as I
touched the lock switch.
The iPod works and charges just fine except for that particular combination
of parts.
Questions:
In general, how is it that an iPod can give me an electric, non-static
shock? Â I thought that USB was only 5V. How does more than 5V get into the
system? Â Or more appropriately, how does it get out of the system? Â Could
this happen from a 12V system, or is part of the 120V getting through?
Thanks for tolerating a non-airplane topic,
--Dave Saylor
________________________________ Â Message 17 Â ____________________________________
Time: 11:48:32 PM PST US
Subject: Re: How is it I get a shock from an iPod?
From: Etienne Phillips <etienne.phillips(at)gmail.com (etienne.phillips(at)gmail.com)>
Hi Dave
I think it's an Apple thing - I get zapped by my aluminium Macbook Pro,
exactly how you describe it - when it's plugged in. Sometimes it's actually
painful, since the skin in the inner arms is pretty sensitive! I don't know
if it's any different here in a 220V country, but I'd really like to get to
the bottom of it. It's happened at multiple locations, which leads me to
believe that it's also not affected by the supply wiring.
Thanks
Etienne
On 25 June 2014 07:49, Dave Saylor <dave.saylor.aircrafters(at)gmail.com (dave.saylor.aircrafters(at)gmail.com)>
wrote:
> Here's a non-aviation question for the group. Â Unless you fly with an
> iPod, I guess.
>
> Background:
>
> My son complained today that he got shocked by an iPod. Â FWIW, it's a 5th
> gen nano plugged into an Apple USB charging cube by an Apple charging
> cord--not knock-off parts. Â First I said yeah, right...but he insisted so
> like an idiot I figured I'd show him how that was impossible....and of
> course I got shocked too. Â Not as strong as 120VAC but enough to get my
> attention.
>
> We were both barefoot (key, I think...) on a concrete slab, in the garage.
> Â It happened when either of us touched the metal lock switch. Â I've never
> had any issues with the power strip we were using.
>
> Putting a meter between the lock switch and ground I measure an
> invigorating 60VAC. Â Between the neutral of the power strip to any other
> ground is zero, so I figure the power strip is wired correctly. Inverting
> the cube (it's not polarized) makes no difference, still 60VAC.
>
> I tried a few things: different plug, no shock. Â Different cord, no shock.
> Â Different cube, no shock. Â I went back to the original combination:
> Â BZZZZT. Â So it is repeatable.
>
> There's an Apple support document describing the possibility of static
> shock when using their device. Â This was not your typical
> feet-on-carpet-touch-a-doorknob static shock. It was sustained as long as I
> touched the lock switch.
>
> The iPod works and charges just fine except for that particular
> combination of parts.
>
> Questions:
>
> In general, how is it that an iPod can give me an electric, non-static
> shock? Â I thought that USB was only 5V. How does more than 5V get into the
> system? Â Or more appropriately, how does it get out of the system? Â Could
> this happen from a 12V system, or is part of the 120V getting through?
>
> Thanks for tolerating a non-airplane topic,
>
> --Dave Saylor
>
> *
>
>
> *
>
>
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enginerdy(at)gmail.com
Guest
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| Posted: Wed Jun 25, 2014 6:45 am Post subject: iPod shocks |
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The puzzling thing is that there should be no path for these kinds of shocks, no matter what...
See Ken Shirriff's teardown of an apple charger here:
http://www.righto.com/2012/05/apple-iphone-charger-teardown-quality.html
and here:
http://www.righto.com/2014/05/a-look-inside-ipad-chargers-pricey.html
Is the voltage between neutral and ground zero *when it's plugged in*? I wonder if you don't have some resistance there or something that develops a voltage only when there is a load applied. Very odd.
On Jun 25, 2014, at 9:18 AM, GLEN MATEJCEK <fly4grins(at)gmail.com (fly4grins(at)gmail.com)> wrote:
[quote] | Quote: | | Hi Guys- it sounds like you are getting a half wave tickle, which could imply that the guts of the device are intended for a polarized plug while the polarized plug itself is absent. If that is the case, each time you plug in you would have a 50 / 50 chance of getting a have wave zap, 60v here and 110 v for Etienne. I'd repeat the V measurement excercise twice, once with each plug / recceptacle orientation. If you get 1/2 line V one way and zero the other, there you go. |
| Quote: |
Time: 10:51:06 PM PST US
From: Dave Saylor <dave.saylor.aircrafters(at)gmail.com (dave.saylor.aircrafters(at)gmail.com)>
Subject: How is it I get a shock from an iPod?
Here's a non-aviation question for the group. Unless you fly with an iPod,
I guess.
Background:
My son complained today that he got shocked by an iPod. FWIW, it's a 5th
gen nano plugged into an Apple USB charging cube by an Apple charging
cord--not knock-off parts. First I said yeah, right...but he insisted so
like an idiot I figured I'd show him how that was impossible....and of
course I got shocked too. Not as strong as 120VAC but enough to get my
attention.
We were both barefoot (key, I think...) on a concrete slab, in the garage.
It happened when either of us touched the metal lock switch. I've never
had any issues with the power strip we were using.
Putting a meter between the lock switch and ground I measure an
invigorating 60VAC. Between the neutral of the power strip to any other
ground is zero, so I figure the power strip is wired correctly. Inverting
the cube (it's not polarized) makes no difference, still 60VAC.
I tried a few things: different plug, no shock. Different cord, no shock.
Different cube, no shock. I went back to the original combination:
BZZZZT. So it is repeatable.
There's an Apple support document describing the possibility of static
shock when using their device. This was not your typical
feet-on-carpet-touch-a-doorknob static shock. It was sustained as long as I
touched the lock switch.
The iPod works and charges just fine except for that particular combination
of parts.
Questions:
In general, how is it that an iPod can give me an electric, non-static
shock? I thought that USB was only 5V. How does more than 5V get into the
system? Or more appropriately, how does it get out of the system? Could
this happen from a 12V system, or is part of the 120V getting through?
Thanks for tolerating a non-airplane topic,
--Dave Saylor
________________________________ Message 17 ____________________________________
Time: 11:48:32 PM PST US
Subject: Re: How is it I get a shock from an iPod?
From: Etienne Phillips <etienne.phillips(at)gmail.com (etienne.phillips(at)gmail.com)>
Hi Dave
I think it's an Apple thing - I get zapped by my aluminium Macbook Pro,
exactly how you describe it - when it's plugged in. Sometimes it's actually
painful, since the skin in the inner arms is pretty sensitive! I don't know
if it's any different here in a 220V country, but I'd really like to get to
the bottom of it. It's happened at multiple locations, which leads me to
believe that it's also not affected by the supply wiring.
Thanks
Etienne
On 25 June 2014 07:49, Dave Saylor <dave.saylor.aircrafters(at)gmail.com (dave.saylor.aircrafters(at)gmail.com)>
wrote:
> Here's a non-aviation question for the group. Unless you fly with an
> iPod, I guess.
>
> Background:
>
> My son complained today that he got shocked by an iPod. FWIW, it's a 5th
> gen nano plugged into an Apple USB charging cube by an Apple charging
> cord--not knock-off parts. First I said yeah, right...but he insisted so
> like an idiot I figured I'd show him how that was impossible....and of
> course I got shocked too. Not as strong as 120VAC but enough to get my
> attention.
>
> We were both barefoot (key, I think...) on a concrete slab, in the garage.
> It happened when either of us touched the metal lock switch. I've never
> had any issues with the power strip we were using.
>
> Putting a meter between the lock switch and ground I measure an
> invigorating 60VAC. Between the neutral of the power strip to any other
> ground is zero, so I figure the power strip is wired correctly. Inverting
> the cube (it's not polarized) makes no difference, still 60VAC.
>
> I tried a few things: different plug, no shock. Different cord, no shock.
> Different cube, no shock. I went back to the original combination:
> BZZZZT. So it is repeatable.
>
> There's an Apple support document describing the possibility of static
> shock when using their device. This was not your typical
> feet-on-carpet-touch-a-doorknob static shock. It was sustained as long as I
> touched the lock switch.
>
> The iPod works and charges just fine except for that particular
> combination of parts.
>
> Questions:
>
> In general, how is it that an iPod can give me an electric, non-static
> shock? I thought that USB was only 5V. How does more than 5V get into the
> system? Or more appropriately, how does it get out of the system? Could
> this happen from a 12V system, or is part of the 120V getting through?
>
> Thanks for tolerating a non-airplane topic,
>
> --Dave Saylor
>
> *
>
>
> *
>
>
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etienne.phillips(at)gmail
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| Posted: Wed Jun 25, 2014 6:47 am Post subject: iPod shocks |
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Hi Glen
I've tried swapping the plug around, with no improvement. The charger is supplied with a non-polarized 2-pin plug on the end, so it's being used as intended (certainly as intended by Apple, but maybe not by the people who designed the insides - if not Apple).
This isn't an isolated incident, it happened on my previous Macbook Pro (7 years ago) and happened in the iStore last week on the latest generation stuff. I'm not saying it's right, as it certainly isn't pleasant - but it doesn't seem as though Apple is taking complaints about it too seriously.
I'll try and remember to take a voltage measurement tonight to see how bad it is. What is interesting is that it zaps me no matter how well I'm insulated from the floor.
Etienne
On 25 June 2014 16:18, GLEN MATEJCEK <fly4grins(at)gmail.com (fly4grins(at)gmail.com)> wrote:
[quote] | Quote: | | Hi Guys- Â it sounds like you are getting a half wave tickle, which could imply that the guts of the device are intended for a polarized plug while the polarized plug itself is absent. Â If that is the case, each time you plug in you would have a 50 / 50 chance of getting a have wave zap, 60v here and 110 v for Etienne. Â I'd repeat the V measurement excercise twice, once with each plug / recceptacle orientation. Â If you get 1/2 line V one way and zero the other, there you go. |
[b]
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james(at)etravel.org
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| Posted: Wed Jun 25, 2014 7:03 am Post subject: iPod shocks |
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Hi Etienne,Â
Same here in the UK, but with a Toshiba laptop. Â Some of the black coating has rubbed off the left-hand front corner of the laptop, revealing a tiny 1x1mm bit of metal... right where my wrist is. Â When it's plugged in, I get a shock from it; when it's not, I don't. Â Here in the UK, all sockets are wired the same way, with specific L, N & E terminals. Â
FWIW.Â
James
p.s. a further oddity. Â If I run my finger along the laptop, for example next to the mousepad, it sort of "drags" when the laptop's plugged in... when it's not, there's no friction at all. Â Go figure!
On 25 June 2014 15:46, Etienne Phillips <etienne.phillips(at)gmail.com (etienne.phillips(at)gmail.com)> wrote:
[quote]Hi Glen
I've tried swapping the plug around, with no improvement. The charger is supplied with a non-polarized 2-pin plug on the end, so it's being used as intended (certainly as intended by Apple, but maybe not by the people who designed the insides - if not Apple).
This isn't an isolated incident, it happened on my previous Macbook Pro (7 years ago) and happened in the iStore last week on the latest generation stuff. I'm not saying it's right, as it certainly isn't pleasant - but it doesn't seem as though Apple is taking complaints about it too seriously.
I'll try and remember to take a voltage measurement tonight to see how bad it is. What is interesting is that it zaps me no matter how well I'm insulated from the floor.
Etienne
On 25 June 2014 16:18, GLEN MATEJCEK <fly4grins(at)gmail.com (fly4grins(at)gmail.com)> wrote:
| Quote: | | Quote: | | Hi Guys- Â it sounds like you are getting a half wave tickle, which could imply that the guts of the device are intended for a polarized plug while the polarized plug itself is absent. Â If that is the case, each time you plug in you would have a 50 / 50 chance of getting a have wave zap, 60v here and 110 v for Etienne. Â I'd repeat the V measurement excercise twice, once with each plug / recceptacle orientation. Â If you get 1/2 line V one way and zero the other, there you go. |
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dave.saylor.aircrafters(a
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| Posted: Wed Jun 25, 2014 6:12 pm Post subject: iPod shocks |
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Thanks to everyone who replied. Â This is such a great resource, I never get tired of the discussion.
I did some more checking. Â My garage wiring seems to be fine. Â Can't find any fault there. Â I really do appreciate the concern, you guys are great.
As for the half wave, even with polarity reversed, same effect.
I tried a couple more chargers. Â A different Belkin charger gives me a 45V potential to ground. Â I have one of the dedicated USB receptacles that wires into a wall plug. Â It only gives me about 3V, which I figure is maybe just noise.
And I tried a few more locations for the chargers. Â They seem to give the same result no matter where they're plugged in.
Same result with two iPods and an iPhone. Â Nothing, though, with an iPad that uses the new type of mini plug.
So the problem seems to be in the charger, some worse than others. Â I think the big difference was being barefoot on the concrete slab. Â That gave a great path to ground, courtesy of yours truly.
I'm getting a new charger!
--Dave
On Wed, Jun 25, 2014 at 8:02 AM, James Kilford <james(at)etravel.org (james(at)etravel.org)> wrote:
[quote] Hi Etienne,Â
Same here in the UK, but with a Toshiba laptop. Â Some of the black coating has rubbed off the left-hand front corner of the laptop, revealing a tiny 1x1mm bit of metal... right where my wrist is. Â When it's plugged in, I get a shock from it; when it's not, I don't. Â Here in the UK, all sockets are wired the same way, with specific L, N & E terminals. Â
FWIW.Â
James
p.s. a further oddity. Â If I run my finger along the laptop, for example next to the mousepad, it sort of "drags" when the laptop's plugged in... when it's not, there's no friction at all. Â Go figure!
On 25 June 2014 15:46, Etienne Phillips <etienne.phillips(at)gmail.com (etienne.phillips(at)gmail.com)> wrote:
| Quote: | Hi Glen
I've tried swapping the plug around, with no improvement. The charger is supplied with a non-polarized 2-pin plug on the end, so it's being used as intended (certainly as intended by Apple, but maybe not by the people who designed the insides - if not Apple).
This isn't an isolated incident, it happened on my previous Macbook Pro (7 years ago) and happened in the iStore last week on the latest generation stuff. I'm not saying it's right, as it certainly isn't pleasant - but it doesn't seem as though Apple is taking complaints about it too seriously.
I'll try and remember to take a voltage measurement tonight to see how bad it is. What is interesting is that it zaps me no matter how well I'm insulated from the floor.
Etienne
On 25 June 2014 16:18, GLEN MATEJCEK <fly4grins(at)gmail.com (fly4grins(at)gmail.com)> wrote:
| Quote: | | Quote: | | Hi Guys- Â it sounds like you are getting a half wave tickle, which could imply that the guts of the device are intended for a polarized plug while the polarized plug itself is absent. Â If that is the case, each time you plug in you would have a 50 / 50 chance of getting a have wave zap, 60v here and 110 v for Etienne. Â I'd repeat the V measurement excercise twice, once with each plug / recceptacle orientation. Â If you get 1/2 line V one way and zero the other, there you go. |
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fly4grins(at)gmail.com
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| Posted: Thu Jun 26, 2014 6:30 am Post subject: iPod shocks |
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Ah well; Â So much for the polarization theory. Â I'd love to understand the voltage-induced perception of friction, though. Â Any electro-physio engineers out there?
[quote][b]
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dave.saylor.aircrafters(a
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etienne.phillips(at)gmail
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| Posted: Thu Jun 26, 2014 7:49 am Post subject: iPod shocks |
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The sensation of friction is quite often characterized as a vibration as the finger catches and slides on a surface (think of a slightly damp finger across a window pane). With the 50 or 60Hz shocks, the nerves on the skin are tricked into the sensation of a vibration, which is interpreted as friction.
Etienne
On 26 June 2014 16:29, GLEN MATEJCEK <fly4grins(at)gmail.com (fly4grins(at)gmail.com)> wrote:
[quote]Ah well; Â So much for the polarization theory. Â I'd love to understand the voltage-induced perception of friction, though. Â Any electro-physio engineers out there?
[b]
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fly4grins(at)gmail.com
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| Posted: Fri Jun 27, 2014 4:53 am Post subject: iPod shocks |
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Thanks Etienne - that would make sense. >The sensation of friction is quite often characterized as a vibration as >the finger catches and slides on a surface (think of a slightly damp finger>across a window pane). With the 50 or 60Hz shocks, the nerves on the skin >are tricked into the sensation of a vibration, which is interpreted as>friction.
[quote][b]
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nuckolls.bob(at)aeroelect
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| Posted: Fri Jun 27, 2014 7:41 am Post subject: iPod shocks |
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At 09:10 PM 6/25/2014, you wrote:
| Quote: | Thanks to everyone who replied. Â This is such a great resource, I never get tired of the discussion.
I did some more checking. Â My garage wiring seems to be fine. Â Can't find any fault there. Â I really do appreciate the concern, you guys are great.
As for the half wave, even with polarity reversed, same effect. |
Interesting thread . . . I'd like to understand more
about the nature and root cause of Dave's observations.
I'm not aware of any line operated power supply
wherein the designer did not observe the most
rudimentary of design goals for user safety.
Consider this exchange between a DIY wall-wart
wannabe and some cooler heads . . .
http://tinyurl.com/omf3xg2
From day-one for unregulated, transformer/rectifier/
capacitor wall warts to present-day transformer/
switchmode regulators . . . the consumer product
wall warts have always featured transformer isolation between
any connection to AC mains and connections accessible
to the consumer.
To gain UL approvals, all power supplies are
evaluated for potential leakage, arcing or
mechanical failures that would pose a risk
for loss of such protection.
This view of the interior of a modern, ac-mains
dc supply shows the tiny transformer (tiny because
it operates at frequencies much higher than ac-mains
60Hz) which has been clearly marked "HiPot OK"
and a date-code of 49th week of 1999.
A 'hi-pot' test calls for deliberate application of hundreds
of volts across the insulation between the transformer's
'line-side' and 'consumer-side' windings. Leakages of
more than a few microamps gets the transformer rejected.
Dave's observations are probably based on a degraded assembly,
possibley due to some combination of dust/moisture . . . or
breakdown of the transformer's insulation.
I've asked Dave for the carcass . . . it would be interesting
to see if root cause for his observations can be identified.
Suffice it to say, there is very little risk for repeated
experiences for any of millions of examples of ac-mains
operated power supplies. Making them safe is easier
than making them work good. Selective purchasing decisions
based on brand names is not particularly useful . . .
the most revered of brands may exploit the economies of
outside production support . . . for which they will
have developed a requirements document. A document that
most certainly includes the value of designing for
'hi-pot' tests . . .
Bob . . . [quote][b]
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dave.saylor.aircrafters(a
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| Posted: Fri Jun 27, 2014 8:55 am Post subject: iPod shocks |
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Bob,
You should have it in a couple days.
I said in my post that it was an Apple device--it's not. Â It is a knock-off, with no marking except Made in China to instill consumer confidence...
--Dave
On Fri, Jun 27, 2014 at 8:40 AM, Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)> wrote:
[quote] At 09:10 PM 6/25/2014, you wrote:
| Quote: | Thanks to everyone who replied. Â This is such a great resource, I never get tired of the discussion.
I did some more checking. Â My garage wiring seems to be fine. Â Can't find any fault there. Â I really do appreciate the concern, you guys are great.
As for the half wave, even with polarity reversed, same effect. |
 Interesting thread . . . I'd like to understand more
 about the nature and root cause of Dave's observations.
 I'm not aware of any line operated power supply
 wherein the designer did not observe the most
 rudimentary of design goals for user safety.
 Consider this exchange between a DIY wall-wart
 wannabe and some cooler heads . . .
http://tinyurl.com/omf3xg2
 From day-one for unregulated, transformer/rectifier/
 capacitor wall warts to present-day transformer/
 switchmode regulators . . . the consumer product
 wall warts have always featured transformer isolation between
 any connection to AC mains and connections accessible
 to the consumer.
 To gain UL approvals, all power supplies are
 evaluated for potential leakage, arcing or
 mechanical failures that would pose a risk
 for loss of such protection.
 This view of the interior of a modern, ac-mains
 dc supply shows the tiny transformer (tiny because
 it operates at frequencies much higher than ac-mains
 60Hz) which has been clearly marked "HiPot OK"
 and a date-code of 49th week of 1999.
Â
 A 'hi-pot' test calls for deliberate application of hundreds
 of volts across the insulation between the transformer's
 'line-side' and 'consumer-side' windings. Leakages of
 more than a few microamps gets the transformer rejected.
 Dave's observations are probably based on a degraded assembly,
 possibley due to some combination of dust/moisture . . . or
 breakdown of the transformer's insulation.
 I've asked Dave for the carcass . . . it would be interesting
 to see if root cause for his observations can be identified.
 Suffice it to say, there is very little risk for repeated
 experiences for any of millions of examples of ac-mains
 operated power supplies. Making them safe is easier
 than making them work good. Selective purchasing decisions
 based on brand names is not particularly useful . . .
 the most revered of brands may exploit the economies of
 outside production support . . . for which they will
 have developed a requirements document. A document that
 most certainly includes the value of designing for
 'hi-pot' tests . . .
 Bob . . . | Quote: |
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mmayfield
Joined: 09 Oct 2009
Posts: 40
Location: NSW Central Coast, Australia
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| Posted: Sun Jun 29, 2014 5:51 pm Post subject: Re: iPod shocks |
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FYI, here in Australia a couple of days ago a young woman was electrocuted and killed by a dodgy knock-off phone charger.
She was talking on the phone plugged into the charger while wearing headphones plugged into her laptop, which was plugged into another wall socket. This completed the electrical circuit which ran from the faulty phone charger through her hand, up and out through her ears, into the laptop and back into the house supply.
The knockoff charger (like many knockoffs) did not comply with national electrical safety standards and needless to say, there has now been a massive crackdown by the authorities on stores and markets selling cheap import chargers which are non-compliant.
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dave.saylor.aircrafters(a
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| Posted: Sun Jun 29, 2014 8:34 pm Post subject: iPod shocks |
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That's tragic. Â I can imagine lots of people putting themselves in a similar situation.
BTW, for those wondering if this is an urban legend, here's a link to a recent news article:
http://www.dailymail.co.uk/news/article-2671493/Woman-dies-electrocuted-headphones-plugged-laptop.html
I've learned my lesson. Â No more cheapo chargers.
--Dave
On Sun, Jun 29, 2014 at 6:51 PM, mmayfield <mmayfield(at)ozemail.com.au (mmayfield(at)ozemail.com.au)> wrote:
[quote] --> AeroElectric-List message posted by: "mmayfield" <mmayfield(at)ozemail.com.au (mmayfield(at)ozemail.com.au)>
FYI, here in Australia a couple of days ago a young woman was electrocuted and killed by a dodgy knock-off phone charger.
She was talking on the phone plugged into the charger while wearing headphones plugged into her laptop, which was plugged into another wall socket. This completed a 240V circuit which ran from the faulty phone charger through her hand, up and out through her ears, into the laptop and back into the house supply.
The knockoff charger (like many knockoffs) did not comply with national electrical safety standards and needless to say, there has now been a massive crackdown by the authorities on stores and markets selling cheap import chargers which are non-compliant.
--------
Mike
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=425746#425746
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Eric M. Jones
Joined: 10 Jan 2006
Posts: 565
Location: Massachusetts
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| Posted: Mon Jun 30, 2014 7:01 am Post subject: Re: iPod shocks |
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I once dated a lovely woman whose bathtub edge was furnished with a small TV, a hair dryer, a radio, and a hair curler heater.
And no, there was no sort of Ground Fault Protection socket anywhere. And yes, I tried to set her straight.
Let's be careful out there. do not archive
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113 Brentwood Drive
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(508) 764-2072
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trigo(at)mail.telepac.pt
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| Posted: Mon Jun 30, 2014 7:21 am Post subject: iPod shocks |
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Eric
Was she pretty?
Did she become rigid carbon blacK?
Carlos
Do not archive ... me
--
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nuckolls.bob(at)aeroelect
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| Posted: Wed Jul 09, 2014 12:15 pm Post subject: iPod shocks |
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Got out to the lab this morning with Dave's 'tingly'
wall-wart. Connected the two ac mains tabs together
as one terminal. Tied all wires in a USB cable together
and stuck the connector into the wall-wart's output
jack.
The test-set I had access to didn't offer the 1,500 VAC/
2,200 VDC test levels commonly used for line powered
equipment.
Made three 'hi-pot' measurements at 250, 500 and
1000 VDC each. All the average value of measured
leakage resistance was 55,000 ohms.
One would have liked to test this power supply at
about 2200 VDC and look for a leakage current
less that 0.5 mA translating to a resistance on
the order of 4.4 Megohms.
The relative stability of leakage resistance over
the 250-1000 VDC test range suggests that barring
arc-over failure, the leakage current at 2200 volts
would be on the order of 2200/55,000 = 0.04A or
abut 80x the test target.
I disassembled the test article to capture these
images.
http://tinyurl.com/oxbyprq
http://tinyurl.com/oahyg4a
http://tinyurl.com/pfbsxbo
http://tinyurl.com/pjnwyom
I'll do some additional testing to see if I can
repeat Dave's measurements at the wall socket. But
in any case, this particular design would probably
not pass any organization's safety testing
reqluirements.
Bob . . .
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saylor.dave(at)gmail.com
Guest
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| Posted: Wed Jul 09, 2014 6:12 pm Post subject: iPod shocks |
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Thanks Bob. Â Glad to know it's not just me!
do not archive
On Wed, Jul 9, 2014 at 1:13 PM, Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)> wrote:
[quote]--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)>
Got out to the lab this morning with Dave's 'tingly'
wall-wart. Connected the two ac mains tabs together
as one terminal. Tied all wires in a USB cable together
and stuck the connector into the wall-wart's output
jack.
The test-set I had access to didn't offer the 1,500 VAC/
2,200 VDC test levels commonly used for line powered
equipment.
Made three 'hi-pot' measurements at 250, 500 and
1000 VDC each. All the average value of measured
leakage resistance was 55,000 ohms.
One would have liked to test this power supply at
about 2200 VDC and look for a leakage current
less that 0.5 mA translating to a resistance on
the order of 4.4 Megohms.
The relative stability of leakage resistance over
the 250-1000 VDC test range suggests that barring
arc-over failure, the leakage current at 2200 volts
would be on the order of 2200/55,000 = 0.04A or
abut 80x the test target.
I disassembled the test article to capture these
images.
http://tinyurl.com/oxbyprq
http://tinyurl.com/oahyg4a
http://tinyurl.com/pfbsxbo
http://tinyurl.com/pjnwyom
I'll do some additional testing to see if I can
repeat Dave's measurements at the wall socket. But
in any case, this particular design would probably
not pass any organization's safety testing
reqluirements.
 Bob . . . Â
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Eric M. Jones
Joined: 10 Jan 2006
Posts: 565
Location: Massachusetts
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| Posted: Thu Jul 10, 2014 5:31 am Post subject: Re: iPod shocks |
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Bob,
Electrocution seems to be normal with these devices! Google "IPod electric shocks" and see the many Apple Devotees who don't think it is a big deal. Some get tingles across their ear-buds. Remarkable.
As for the one you tested, the transformer is always the problem. It looks like there is room in there for a legal transformer. Double-bobbin is best.
I can't see how Apple doesn't have a class-action suit pending. Perhaps they are using the Pinto lawsuit calculator--fixing 4.5 billion units vs X dead victims' lawsuits per year...who probably were on Ecstasy and had weak hearts anyway. Hmmmmm.
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_________________
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge, MA 01550
(508) 764-2072
emjones(at)charter.net |
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