Tingles from DVD players

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Russ_Verdon

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Mar 19, 2006, 4:24:36 AM3/19/06
to
Hi, I just did a round of "kerbside shopping" and picked up 2x Digitor DVD
players from the same place. They both work. The only thing I can think is
that they give you a small shock between their chassis and power earth. I
can only surmise that the owner thought they were faulty and ditched them as
a result. I have picked up another DVD player in similar circunstances,
going, but tingling.
I believe the shock would be some capacitive coupling to their chassis from
the switchmode PS. I can measure 105 volts AC from their chassis to earth,
but no current .
Is there any rule that stops you earthing these devices, given that the
connection via the signal leads to an earthed amp etc would probably do this
anyway?
Do the manufacturers expect all devices to be turned off so that customers
don't experience shocks when changing leads around? If chassis earthing
elminates this issue, then it would be a nice feature and customer friendly
to do so. I guess the amount of copper / star washer etc saved per unit for
them outweighs thoughts for the customer.
Any comments?

Russell


Phil Allison

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Mar 19, 2006, 5:08:59 AM3/19/06
to

"Russ_Verdon"

>
> Hi, I just did a round of "kerbside shopping" and picked up 2x Digitor
> DVD
> players from the same place. They both work. The only thing I can think is
> that they give you a small shock between their chassis and power earth. I
> can only surmise that the owner thought they were faulty and ditched them
> as
> a result. I have picked up another DVD player in similar circunstances,
> going, but tingling.
> I believe the shock would be some capacitive coupling to their chassis
> from
> the switchmode PS. I can measure 105 volts AC from their chassis to earth,
> but no current .
> Is there any rule that stops you earthing these devices, given that the
> connection via the signal leads to an earthed amp etc would probably do
> this
> anyway?


** Yes - the units are not longer "double insulated" or of "class 2"
construction if you substitute a 3 core lead.


> Do the manufacturers expect all devices to be turned off so that customers
> don't experience shocks when changing leads around?


** Only a few folk feel any tingle at all.


> If chassis earthing
> elminates this issue, then it would be a nice feature and customer
> friendly
> to do so.


** Completely silly.

The use of Class 2 construction is a VERY deliberate decision and for very
good reasons.


>I guess the amount of copper / star washer etc saved per unit for
> them outweighs thoughts for the customer.


** Absolute crapology.

> Any comments?


** You seriously temp me.

Never heard of earth loop hum ?????


......... Phil

Chris Jones

unread,
Mar 19, 2006, 1:21:19 PM3/19/06
to
Phil Allison wrote:

>
> "Russ_Verdon"
>>
>> Hi, I just did a round of "kerbside shopping" and picked up 2x Digitor
>> DVD
>> players from the same place. They both work. The only thing I can think
>> is that they give you a small shock between their chassis and power
>> earth. I can only surmise that the owner thought they were faulty and
>> ditched them as
>> a result. I have picked up another DVD player in similar circunstances,
>> going, but tingling.
>> I believe the shock would be some capacitive coupling to their chassis
>> from
>> the switchmode PS. I can measure 105 volts AC from their chassis to
>> earth, but no current .
>> Is there any rule that stops you earthing these devices, given that the
>> connection via the signal leads to an earthed amp etc would probably do
>> this
>> anyway?
>
>
> ** Yes - the units are not longer "double insulated" or of "class 2"
> construction if you substitute a 3 core lead.

Sure, that seems obvious. The device would then be modified, the original
electrical approval would not be valid, and it would not be possible to
approve the device as a class 2 device with the case earthed. Are you
aware of any technical reason why the device could not be approved as a
class 1 device (hypothetically, since the cost of testing would be more
than prohibitive)? To the best of my knowledge the insulation requirements
of a class 2 device are more strict than would be required for a class 1
device, though I don't know if there are any fusing requirements for class
1 which would not have applied to the class 2 device when it was built.

>
>> Do the manufacturers expect all devices to be turned off so that
>> customers don't experience shocks when changing leads around?
>
>
> ** Only a few folk feel any tingle at all.
>
>
>> If chassis earthing
>> elminates this issue, then it would be a nice feature and customer
>> friendly
>> to do so.
>
>
> ** Completely silly.
>
> The use of Class 2 construction is a VERY deliberate decision and for very
> good reasons.

Apart from the earth loop hum you refer to, what reasons are you referring
to?

>
>
>>I guess the amount of copper / star washer etc saved per unit for
>> them outweighs thoughts for the customer.
>
>
> ** Absolute crapology.
>
>> Any comments?
>
>
> ** You seriously temp me.
>
> Never heard of earth loop hum ?????
>
>
>
>
> ......... Phil

Chris


Phil Allison

unread,
Mar 19, 2006, 6:04:18 PM3/19/06
to

"Chris Jones"

> Phil Allison wrote:
>>
>>> Is there any rule that stops you earthing these devices, given that the
>>> connection via the signal leads to an earthed amp etc would probably do
>>> this
>>> anyway?
>>
>>
>> ** Yes - the units are not longer "double insulated" or of "class 2"
>> construction if you substitute a 3 core lead.
>
> Sure, that seems obvious.


** You have completely missed the point.


> The device would then be modified, the original
> electrical approval would not be valid,


** Correct - so the markings on the unit (ie "class 2" and the double
square symbols) would be then ILLEGAL.


> and it would not be possible to
> approve the device as a class 2 device with the case earthed. Are you
> aware of any technical reason why the device could not be approved as a
> class 1 device (hypothetically, since the cost of testing would be more
> than prohibitive)?


** Yawn.

This is an entirely separate issue to the OP's question AND my reply.

>>
>>> If chassis earthing elminates this issue, then it would be a nice
>>> feature and customer friendly to do so.
>>
>>
>> ** Completely silly.
>>
>> The use of Class 2 construction is a VERY deliberate decision and for
>> very
>> good reasons.
>
> Apart from the earth loop hum you refer to, what reasons are you referring
> to?


** 1. Class 2 construction is far SAFER for the user.

2. Class 2 construction meets world wide electrical approvals making it far
easier for makers to market the same design world wide.

3. The use of class 2 is almost universal for some classes of electronic
equipment.

4. There is a PROHIBITION on interconnecting class 1 and class 2 equipment.

........ Phil


Jasen Betts

unread,
Mar 20, 2006, 2:20:55 AM3/20/06
to
On 2006-03-19, Phil Allison <phila...@tpg.com.au> wrote:

>>> ** Completely silly.
>>>
>>> The use of Class 2 construction is a VERY deliberate decision and for
>>> very
>>> good reasons.
>>
>> Apart from the earth loop hum you refer to, what reasons are you referring
>> to?
>
> ** 1. Class 2 construction is far SAFER for the user.
>
> 2. Class 2 construction meets world wide electrical approvals making it far
> easier for makers to market the same design world wide.
>
> 3. The use of class 2 is almost universal for some classes of electronic
> equipment.
>
> 4. There is a PROHIBITION on interconnecting class 1 and class 2 equipment.

like a laplink cable?

Bye.
Jasen

Phil Allison

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Mar 20, 2006, 5:26:02 AM3/20/06
to

"Jasen Betts" <ja...@free.net.nz>


> like a laplink cable?

** Piss off - kiwi tenth wit.

The sheep are missing you.

....... Phil


Chris Jones

unread,
Mar 21, 2006, 7:46:23 PM3/21/06
to
Phil Allison wrote:

>
> "Chris Jones"
>> Phil Allison wrote:
>>>
>>>> Is there any rule that stops you earthing these devices, given that the
>>>> connection via the signal leads to an earthed amp etc would probably do
>>>> this
>>>> anyway?
>>>
>>>
>>> ** Yes - the units are not longer "double insulated" or of "class 2"
>>> construction if you substitute a 3 core lead.
>>
>> Sure, that seems obvious.
>
>
> ** You have completely missed the point.
>
>
>> The device would then be modified, the original
>> electrical approval would not be valid,
>
>
> ** Correct - so the markings on the unit (ie "class 2" and the double
> square symbols) would be then ILLEGAL.
>
>
>> and it would not be possible to
>> approve the device as a class 2 device with the case earthed. Are you
>> aware of any technical reason why the device could not be approved as a
>> class 1 device (hypothetically, since the cost of testing would be more
>> than prohibitive)?
>
>
> ** Yawn.
>
> This is an entirely separate issue to the OP's question AND my reply.

Ok but I was interested, in case you know something about it that I could
learn from. I agree that I am slightly changing the subject, however I
thought it worth asking since the OP or others in a similar position might
be inclined to do whatever they feel like, provided they think it is safe,
but in spite of the law. If there were a serious technical reason why it
would be unsafe, rather than a (re)labelling or legal issue then it would
be good to be aware of it.

>>>
>>>> If chassis earthing elminates this issue, then it would be a nice
>>>> feature and customer friendly to do so.
>>>
>>>
>>> ** Completely silly.
>>>
>>> The use of Class 2 construction is a VERY deliberate decision and for
>>> very
>>> good reasons.
>>
>> Apart from the earth loop hum you refer to, what reasons are you
>> referring to?
>
>
> ** 1. Class 2 construction is far SAFER for the user.
>
> 2. Class 2 construction meets world wide electrical approvals making it
> far easier for makers to market the same design world wide.
>
> 3. The use of class 2 is almost universal for some classes of electronic
> equipment.
>
> 4. There is a PROHIBITION on interconnecting class 1 and class 2
> equipment.
>
>
>
>
>
> ........ Phil

I am surprised by (4) since many hi-fi amplifiers (at least older ones) do
have an earthed case, for better or for worse. It is not made very clear
to the average user that connecting the amplifier to a typical (class 2) CD
player would be prohibited, for example I haven't seen such a warning in
the instruction manual of a CD player. I don't have the necessary
knowledge of the standards to refute what you say, but it does surprise me.
Perhaps you mean something different when you say 'interconnecting' from
what I had interpreted, i.e. connecting a shielded audio cable between two
devices, thus connecting their metal cases together. Anyway thanks for
your answer.

Chris

Phil Allison

unread,
Mar 21, 2006, 8:04:07 PM3/21/06
to

"Chris Jones"

** Do you constantly move the goalposts at sporting events too ?

.......... Phil


Phil Allison

unread,
Mar 21, 2006, 8:35:28 PM3/21/06
to

"Chris Jones"
Phil Allison wrote:

>> 4. There is a PROHIBITION on interconnecting class 1 and class 2
>> equipment.
>>

> I am surprised by (4)


** Have you never seen the words " Double Insulated - Do Not Earth " on
the back of a class 2 item ??

Pretty clear isn't it?


> since many hi-fi amplifiers (at least older ones) do
> have an earthed case, for better or for worse. It is not made very clear
> to the average user that connecting the amplifier to a typical (class 2)
> CD
> player would be prohibited,


** It is not prohibited by criminal law - so no police officer will arrest
you for doing it.

But it is an * unsafe practice* that could be considered as " serious
negligence " by a court if a person were injured or killed.


> for example I haven't seen such a warning in
> the instruction manual of a CD player.


** " Double Insulated - Do Not Earth " on the back of the player is a
*stronger warning* that anything printed in a user manual that likely gets
lost with the packaging.

Equipment makers are not liable for what users may WRONGLY do when
interconnecting items of gear - so just ignore the issue.

The matter is very much an *X rated topic * in the home entertainment
electronics industry.


> I don't have the necessary
> knowledge of the standards to refute what you say, but it does surprise
> me.


** Imagine a hi-fi system with every item in it class 2 - so there is no AC
ground to the metalwork.

Next, an item is added to the system, ie a nice old valve tuner just bought
from Ebay but with no AC plug.

Next, the user inadvertently wires up the new plug wrongly with active and
earth reversed and makes all the connections.

The hi-fi system will still work just as before ( but not the tuner) but
with ALL the metalwork, connecting leads and even the loud speakers now
LIVE !!!

In countries with 240 volt AC power, this is a FATAL accident scenario
!!!!


NOTE:

One of the BIGGEST user safety advantages of class 2 construction is that
no matter how WRONGLY the AC plug is wired & no matter what is wrong with
the AC outlet, you cannot get active onto the earth of the gear.


........ Phil


Terry Given

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Mar 22, 2006, 2:41:41 AM3/22/06
to

a major advantage of class 2 is that its cheaper. the plug, cable and
interconnects cost less, and because of the double insulation, none of
the metalwork has to be earthed, which it does with class 1 - for many
standards the metalwork earthing must carry the rated current, further
increasing the cost.

The above scenario can only happen when people fiddle with things, and
so is not relevant to manufacturers (they build them right). Such a
scenario also occurs with a single class 1 appliance wired up by the
same dickhead. Voila, live chassis (and dead operator).

Cheers
Terry


Phil Allison

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Mar 22, 2006, 3:18:02 AM3/22/06
to

"Terry Given"


> a major advantage of class 2 is that its cheaper.

** Bullshit it is.

The specs for the AC supply transformer alone are way beyond that for class
1.

The design rules for every part of the AC side are way tougher.


> the plug, cable and interconnects cost less,


** By a few cents only.


> and because of the double insulation, none of the metalwork has to be
> earthed, which it does with class 1 - for many standards the metalwork
> earthing must carry the rated current, further increasing the cost.


** What absolute drivel.


> The above scenario can only happen when people fiddle with things,


** More " Pinball Wizard " bullshit.


> so is not relevant to manufacturers (they build them right).


** It is *very elevata" to the increased safety of class 2.

It is *very relevant" to the PROHIBITION on earthing a class 2 appliance.

> Such a scenario also occurs with a single class 1 appliance wired up by
> the same dickhead.


** But NOT a system of interconnected class 1 appliances.

Hence the prohibition on earthing a class 2 appliance or system thereof.

They are very safe until you do that.

> Voila, live chassis (and dead operator).


** Please go try it now.


....... Phil


Terry Given

unread,
Mar 22, 2006, 3:48:39 AM3/22/06
to
Phil Allison wrote:
> "Terry Given"
>
>
>
>>a major advantage of class 2 is that its cheaper.
>
>
> ** Bullshit it is.
>
> The specs for the AC supply transformer alone are way beyond that for class
> 1.

double insulation pretty much means 2 sets of insulation, so that when
one fails there is still one left. yes the xfmr is a bit more expensive,
but a whole bunch of other stuff gets cheaper.

look inside a hair dryer, that is far, far cheaper as a class 2 device
than class 1.


>
> The design rules for every part of the AC side are way tougher.
>

not really, and they are made easier by the proliferation of plastic.

>
>
>>the plug, cable and interconnects cost less,
>
>
>
> ** By a few cents only.

why do you think they use phenolic paper PCBs, and an interseting mix of
1%, 5%, 10% and 20% components? when you build 500,000,000 of something,
all them cents add up.


>
>
>
>>and because of the double insulation, none of the metalwork has to be
>>earthed, which it does with class 1 - for many standards the metalwork
>>earthing must carry the rated current, further increasing the cost.
>
>
>
> ** What absolute drivel.
>

Phil has obviously never read BS-EN61010

>
>
>>The above scenario can only happen when people fiddle with things,
>
>
>
> ** More " Pinball Wizard " bullshit.
>
>
>
>>so is not relevant to manufacturers (they build them right).
>
>
>
> ** It is *very elevata" to the increased safety of class 2.
>
> It is *very relevant" to the PROHIBITION on earthing a class 2 appliance.
>
>
>
>
>>Such a scenario also occurs with a single class 1 appliance wired up by
>>the same dickhead.
>
>
>
> ** But NOT a system of interconnected class 1 appliances.

depends on the system, and how they are interconnected.

>
> Hence the prohibition on earthing a class 2 appliance or system thereof.
>
> They are very safe until you do that.
>
>
>
>
>>Voila, live chassis (and dead operator).
>
>
>
> ** Please go try it now.
>
>
>
>
> ....... Phil
>
>

Cheers
Terry

Phil Allison

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Mar 22, 2006, 4:32:59 AM3/22/06
to

"The Pinball Wizard of Nelson "


>>>a major advantage of class 2 is that its cheaper.
>>
>>
>> ** Bullshit it is.
>>
>> The specs for the AC supply transformer alone are way beyond that for
>> class 1.
>
> double insulation pretty much means 2 sets of insulation,


** Absolute bullshit.


> so that when one fails there is still one left.


** Absolute bullshit.


> yes the xfmr is a bit more expensive,


** Much more - the cheapest construction methods are outlawed.

The popular and cheap toroidal is basically outlawed.

> but a whole bunch of other stuff gets cheaper.


** Absolute bullshit.


> look inside a hair


** The subject is DVD players and the like - fuckhead.


>> The design rules for every part of the AC side are way tougher.
>>
>
> not really,


** Get stuffed - Kiwi LIAR !!


....... Phil

Terry Given

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Mar 22, 2006, 6:43:32 AM3/22/06
to
Phil Allison wrote:
> "The Pinball Wizard of Nelson "
>
>
>
>>>>a major advantage of class 2 is that its cheaper.
>>>
>>>
>>>** Bullshit it is.
>>>
>>>The specs for the AC supply transformer alone are way beyond that for
>>>class 1.
>>
>>double insulation pretty much means 2 sets of insulation,
>
>
>
> ** Absolute bullshit.
>
>
>
>>so that when one fails there is still one left.
>
>
>
> ** Absolute bullshit.
>

ROTFLMAO! You are demonstrably wrong, viz.:


first, lets un-snip what I posted:

"double insulation pretty much means 2 sets of insulation, so that when

one fails there is still one left"


AS/NZS3000:2000 Wiring Rules states:

1.4.26 Class II equipment -
Equipment in which protection against electric shock does not rely on
basic insulation only, but in which additional safety precautions such
as double insulation or reinforced insulation are provided, there being
no provision for protective earthing or reliance upon installation
conditions


1.4.57 Insulation System
One, or a combination of, the following:
(a) Basic Insulation - the insulation applied to live parts, to provide
basic protection against electric shock
(b) Supplementary Insulation - an independant insulation applied in
addition to basic insulation in order to ensure protection against
electric shock in the event of a failure of the Basic Insulation
(c) Double Insulation - insulation comprising both Basic Insulation and
Supplementary Insulation

In other words, exactly what I said.

Bwahahahahaha!

>
>
>>yes the xfmr is a bit more expensive,
>
>
>
> ** Much more - the cheapest construction methods are outlawed.

pah. look at those sorts of xfmrs, its not very complex. split bobbins
with lids basically, and a bit more creepage/clearance. they still wind
them with magnet wire; I've yet to see a consumer xfmr wound with
Furukawa Tex-E or any other form of triple-insulated wire....

>
> The popular and cheap toroidal is basically outlawed.
>

on what basis?

and toroids are not that cheap to wind c.f. an e-core bobbin, especially
the little ones (and the big ones)

>
>
>
>>but a whole bunch of other stuff gets cheaper.
>
>
>
> ** Absolute bullshit.
>
>
>
>>look inside a hair
>
>
>
> ** The subject is DVD players and the like - fuckhead.
>
>
>
>>>The design rules for every part of the AC side are way tougher.
>>>
>>
>>not really,
>
>
>
> ** Get stuffed - Kiwi LIAR !!
>
>
>
>
> ....... Phil

Cheers
Terry

Phil Allison

unread,
Mar 22, 2006, 7:21:44 AM3/22/06
to

"The Pinball Wizard of Nelson "


>>>>>a major advantage of class 2 is that its cheaper.
>>>>
>>>>
>>>>** Bullshit it is.
>>>>
>>>>The specs for the AC supply transformer alone are way beyond that for
>>>>class 1.
>>>
>>>double insulation pretty much means 2 sets of insulation,
>>
>
>> ** Absolute bullshit.
>>
>>
>>>so that when one fails there is still one left.
>>
>>
>>
>> ** Absolute bullshit.
>>
>
> ROTFLMAO!


** Go fuck yourself - you useless Kiwi ARSEHOLE .

> first, lets un-snip what I posted:
>
> "double insulation pretty much means 2 sets of insulation, so that when
> one fails there is still one left"


** No.

The term "double insulation" is the popular name for "class 2" construction
= a whole set of technical design rules and restricted materials approvals
that make it * SAFE * to use and sell an appliance that has no connection
to the supply earth as a means of preventing electric shock hazard to users.

All way over this Kiwi fuckwit's pointy head.

> In other words, exactly what I said.


** Wrong context - Kiwi ARSEHOLE.

>>>yes the xfmr is a bit more expensive,
>>
>> ** Much more - the cheapest construction methods are outlawed.
>
> pah. look at those sorts of xfmrs, its not very complex.


** Learn to read - you dumb Kiwi ARSEHOLE.

>> The popular and cheap toroidal is basically outlawed.
>>
>
> on what basis?


** Go read AS3108 some day - ARSEHOLE.

Then figure why toroidals are extremely rare in class 2 gear, consumer or
otherwise.


....... Phil

Malcolm Moore

unread,
Mar 22, 2006, 6:27:24 PM3/22/06
to
On Wed, 22 Mar 2006 12:35:28 +1100, "Phil Allison"
<phila...@tpg.com.au> wrote:

>
>"Chris Jones"
> Phil Allison wrote:
>
>>> 4. There is a PROHIBITION on interconnecting class 1 and class 2
>>> equipment.
>>>
>> I am surprised by (4)
>
>
>** Have you never seen the words " Double Insulated - Do Not Earth " on
>the back of a class 2 item ??
>
> Pretty clear isn't it?

I've just checked all the double insulated items in my home and NONE
of them carry a warning such as you describe. It would be useful to
know how general such a warning is. I suggest everyone reading this
thread check their equipment and report back their findings. My
equipment includes items from NEC, Philips, Sony, Teac, Mitsubishi,
Sanyo & Microsoft.

snip

>Equipment makers are not liable for what users may WRONGLY do when
>interconnecting items of gear - so just ignore the issue.
>
>
>
>The matter is very much an *X rated topic * in the home entertainment
>electronics industry.

So where does the "PROHIBITION" come from?
Previously you said such interconnection was prohibited, now you're
saying to ignore the issue??

>> I don't have the necessary
>> knowledge of the standards to refute what you say, but it does surprise
>> me.
>
>
>** Imagine a hi-fi system with every item in it class 2 - so there is no AC
>ground to the metalwork.
>
>Next, an item is added to the system, ie a nice old valve tuner just bought
>from Ebay but with no AC plug.
>
>Next, the user inadvertently wires up the new plug wrongly with active and
>earth reversed and makes all the connections.
>
>The hi-fi system will still work just as before ( but not the tuner) but
>with ALL the metalwork, connecting leads and even the loud speakers now
>LIVE !!!
>
>In countries with 240 volt AC power, this is a FATAL accident scenario
>!!!!

If this danger was significant then the use of Class 2 equipment is
inherently unsafe because it would be relying on user action to make
it safe, the user action being to not interconnect with other commonly
available items. As you say above, "Equipment makers are not liable
for what users may WRONGLY do.....", but regulators are always
interested in such things. They seem relaxed about the situation.

snip
--
Regards
Malcolm
Remove sharp objects to get a valid e-mail address

Chris Jones

unread,
Mar 22, 2006, 6:38:55 PM3/22/06
to
Phil Allison wrote:

I don't consider posting to usenet to be a competition, though you are free
to consider it whatever you want. I just like to learn stuff.

Chris

Chris Jones

unread,
Mar 22, 2006, 6:59:42 PM3/22/06
to
Phil Allison wrote:

Ok, I can see that wiring the plug of the class 1 device wrongly has made
the class 1 device as well as the class 2 device dangerous to touch. I
think that the user was pretty much asking for a jolt whether or not the
class 2 device was connected (or even existed at all), but in principle I
see why the manufacturer of the class 2 device would not want the two
devices interconnected, so the user gets electrocuted whilst touching the
device made by someone else, that would be cheaper in court....

The root cause of the problem is of course having someone who thinks they
can wire a plug but cannot. The problem is they might not be the one to
get killed, it'll be the neighbour's kid or something like that.

>
>
> NOTE:
>
> One of the BIGGEST user safety advantages of class 2 construction is that
> no matter how WRONGLY the AC plug is wired & no matter what is wrong with
> the AC outlet, you cannot get active onto the earth of the gear.

Thanks, that's the first "class 2 is safer" argument that makes sense to me.
In the context of incompetent and/or amateur electricians, no ELCB, and no
regular testing of power socket wiring and portable appliance testing, I
can see that advantage of class 2. Those conditions are probably fairly
common too.

Chris

Phil Allison

unread,
Mar 22, 2006, 7:50:31 PM3/22/06
to

"Chris Jones"
>
>
>> ** Do you constantly move the goalposts at sporting events too ?
>>
>
> I don't consider posting to usenet to be a competition,


** Then why keep moving the goal posts like is is one you cannot bear to
loose ??

> I just like to learn stuff.


** If you mean that, then why make it impossible for anyone to answer you ?


........ Phil


Phil Allison

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Mar 22, 2006, 8:05:21 PM3/22/06
to

"Malcolm Moore"
"Phil Allison"

>>
>>** Have you never seen the words " Double Insulated - Do Not Earth " on
>>the back of a class 2 item ??
>>
>> Pretty clear isn't it?
>
> I've just checked all the double insulated items in my home and NONE
> of them carry a warning such as you describe.


** The warning notice is not compulsory.

Only the use of the "double square" symbol or the words "Double Insulated"
are.


>The matter is very much an *X rated topic * in the home entertainment
>>electronics industry.
>
> So where does the "PROHIBITION" come from?


** The fact that a class 2 appliance must not be earthed.


> Previously you said such interconnection was prohibited, now you're
> saying to ignore the issue??


** Huh ???

What madman's logic is this ?

What the hell do you think "X -rated " means ???

>>** Imagine a hi-fi system with every item in it class 2 - so there is no
>>AC
>>ground to the metalwork.
>>
>>Next, an item is added to the system, ie a nice old valve tuner just
>>bought
>>from Ebay but with no AC plug.
>>
>>Next, the user inadvertently wires up the new plug wrongly with active and
>>earth reversed and makes all the connections.
>>
>>The hi-fi system will still work just as before ( but not the tuner) but
>>with ALL the metalwork, connecting leads and even the loud speakers now
>>LIVE !!!
>>
>>In countries with 240 volt AC power, this is a FATAL accident scenario
>>!!!!
>
>
> If this danger was significant then the use of Class 2 equipment is
> inherently unsafe because it would be relying on user action to make
> it safe, the user action being to not interconnect with other commonly
> available items.


** Absolute drivel.

Class 2 construction appliances are inherently much safer than class 1
types.

What users do that COMPROMISES that additional safety is beyond the control
of makers or authorities.


>As you say above, "Equipment makers are not liable
> for what users may WRONGLY do.....", but regulators are always
> interested in such things. They seem relaxed about the situation.


** SFA they can do about it.

The issue is one of legal liability on the part of someone who elects to
earth a class 2 item.

........ Phil

Phil Allison

unread,
Mar 22, 2006, 8:28:01 PM3/22/06
to

"Chris Jones"

>
>> In countries with 240 volt AC power, this is a FATAL accident scenario
>> !!!!
>
>
> Ok, I can see that wiring the plug of the class 1 device wrongly has made
> the class 1 device as well as the class 2 device dangerous to touch.


** Not just one device, but an entire hi-fi system INCLUDING the damn
speakers !!!


> I
> think that the user was pretty much asking for a jolt whether or not the
> class 2 device was connected (or even existed at all),


** A third party could be the one electrocuted - maybe a small child.


> but in principle I
> see why the manufacturer of the class 2 device would not want the two
> devices interconnected, so the user gets electrocuted whilst touching the
> device made by someone else, that would be cheaper in court....


** The makers of the class 2 devices are not liable in such a case.

Their items are not permitted to be connected to the earth system of
another.


> The root cause of the problem is of course having someone who thinks they
> can wire a plug but cannot.


** Millions of them around.

Heaps of places sell 3 pin plugs to the public.


> The problem is they might not be the one to
> get killed, it'll be the neighbour's kid or something like that.


** The punishment for mis-wiring a plug ought not be the death of anyone.

>> NOTE:
>>
>> One of the BIGGEST user safety advantages of class 2 construction is
>> that
>> no matter how WRONGLY the AC plug is wired & no matter what is wrong with
>> the AC outlet, you cannot get active onto the earth of the gear.
>
> Thanks, that's the first "class 2 is safer" argument that makes sense to
> me.
> In the context of incompetent and/or amateur electricians, no ELCB, and no
> regular testing of power socket wiring and portable appliance testing, I
> can see that advantage of class 2. Those conditions are probably fairly
> common too.

** The most common cause of electrocution in the home is ( or was until
recently) incorrectly wired plugs and extension leads.

The worst electrocution trap in where BOTH miswired but BOTH work OK unless
the two meet up.

1. The extension lead has active and neutral wires reversed, earth is
wired OK ( most consider this to be harmless).

2. The appliance has earth and neutral wires reversed, active is on the
correct pin ( appliance works fine in normal outlet).


When appliance "2" meets lead " 1" ?????

Death to a toddler.

....... Phil


Message has been deleted

Phil Allison

unread,
Mar 23, 2006, 12:24:12 AM3/23/06
to

"David, not to be confused with the other Davids."

>
>> Is there any rule that stops you earthing these devices, given that the
>> connection via the signal leads to an earthed amp etc would probably
>> do this anyway?
>
> There is no rule in the safety or wiring standards that prevents you from
> doing so,


** Of course there is !!

A Class 2 appliance must not be earthed or it ceases to be one.

> I read some of the other replies and would also like to add the following.
>
> 1. There is no prohibition on interconection of Class 1 and Class 2
> equipment.

** There is.

A Class 2 appliance must not be earthed.


> The only safety related condition is that any earthing required for safety
> of
> the Class 1 device is maintained at the desired level. Which is 1.6 times
> the
> rated current of an inherent protective device (eg. internal fusing).


** You are just making this crazy drivel up.

The earthing requirements for a class 1 appliance relate to the copper cross
section of the earth wire used, ie must not be not less than 1 sq mm. (
AS3100)

> 2. Equipment that was marked "Do Not Earth" was often done so because the
> internal circuitry was "live" and separated from accessible conductive
> parts by
> double/reinforced insulation. Earthing the internal circuitry would be
> potentially hazardous in this case.


** Plenty of class 2 items are labelled "Do Not Earth" where no such thing
existed.

( snip more irrelevant drivel )


> 4. Class 2 construction does not mean double insulation.


** Correct - but the names have become synonyms as far as categorising an
appliance is concerned.


....... Phil


Terry Given

unread,
Mar 23, 2006, 12:58:41 AM3/23/06
to
David, not to be confused with the other Davids. wrote:
> I might as well add my $0.02 worth here too.
>
> "Russ_Verdon" <verdonsATtpgi.com.au> wrote in message
> news:441d...@dnews.tpgi.com.au...

>
>>Hi, I just did a round of "kerbside shopping" and picked up 2x Digitor DVD
>>players from the same place. They both work. The only thing I can think is
>>that they give you a small shock between their chassis and power earth. I
>>can only surmise that the owner thought they were faulty and ditched them as
>>a result. I have picked up another DVD player in similar circunstances,
>>going, but tingling.
>
>
> This is a well known and allowed for condition in safety standards. It is
> referred
> to as "touch current" and was previosuly referred to as leakage current. The
> safe
> limit for touch current in Class 2 devices is 0.25 mA and this lies within the
> perception range for some people. Touch current is likely due to the current
> passing
> through small value capacitors connected between the chassis and the primary
> power circuits. This is usually for ESD (electro-static discharge)
> compatibility in
> the case of audio/video equipment.

>
>
>>Is there any rule that stops you earthing these devices, given that the
>>connection via the signal leads to an earthed amp etc would probably
>>do this anyway?
>
>
> There is no rule in the safety or wiring standards that prevents you from
> doing so, but introducing an earth is not a good idea since it may cause
> unintended earth loop currents to flow through other circuits. This can lead
> to humm and noise, etc.

>
>
>>Do the manufacturers expect all devices to be turned off so that customers
>>don't experience shocks when changing leads around? If chassis earthing
>>elminates this issue, then it would be a nice feature and customer friendly
>>to do so. I guess the amount of copper / star washer etc saved per unit for
>>them outweighs thoughts for the customer.
>>Any comments?
>>
>>Russell
>
>
> Among other reasons, it also has to do with cost, but not as you might imagine.
> By floating the chassis there is no need to use audio baluns or isolating
> transformers in the input and output interconnection stages to remove
> extraneous circulating supply currents or to provide electrical safety.

>
> I read some of the other replies and would also like to add the following.
>
> 1. There is no prohibition on interconection of Class 1 and Class 2 equipment.
> The only safety related condition is that any earthing required for safety of
> the
> Class 1 device is maintained at the desired level. Which is 1.6 times the
> rated
> current of an inherent protective device (eg. internal fusing).
>
> 2. Equipment that was marked "Do Not Earth" was often done so because the
> internal circuitry was "live" and separated from accessible conductive parts by
> double/reinforced insulation. Earthing the internal circuitry would be
> potentially
> hazardous in this case.
>
> More commonly the "do not earth" instruction is for when the equipment is
> supplied to countries that do not have the MEN (TNC-S) mains supply wiring
> scheme. In those countries there is a separate earthing terminal or bonding
> point
> on the equipment chassis, and more often than not, no mains plug is supplied on
> the cord. Equipment that is to be earthed has a plug added, and the chassis
> bonded to
> earth at the time of installation. For floating chassis devices the do not
> earth instruction
> is to specifically draw attention to not to bond to earth.
>
> 3. For small A/V and ITE, making Class 2 equipment costs almost the same as
> Class 1
> equipment.

by "almost" do you mean slightly more or slightly less? I suspect less.


Class 1 is of benefit in high power appliances like toasters,
> ovens, etc.

mostly because the requirements for double- or reinforced-insulation
become difficult, if not impossible.

>
> 4. Class 2 construction does not mean double insulation. Double insulation
> may be a
> type of Class 2 construction but reinforced insulation is now more common.
>
> 5. Someone mentioned triple insulated wire is not common. It is now very
> common,

I was referring to 50/60Hz transformers, although did not specifically
say so. Its the bees knees for smps transformers.

are you aware of any triple-insulated foils?

> being the preferred method to construct very small footprint concentric wound
> transformers in smal SMPSUs. The majority of mobile phone power supplies I
> have examined (say, since 2000) use triple insulated wire as the secondary
> winding.
> This way the static screen and the primary can be conductively coupled, doing
> away
> with the additional layers of insulation that would otherwise be needed.

and it avoids all that creepage, allowing lower leakage designs.

>
> Most of the above can be found in AS/NZS 60065 and/or AS/NZS 60950-1
>
>

Cheers
Terry

Terry Given

unread,
Mar 23, 2006, 1:04:52 AM3/23/06
to
Phil Allison wrote:
> "David, not to be confused with the other Davids."
>
>>>Is there any rule that stops you earthing these devices, given that the
>>>connection via the signal leads to an earthed amp etc would probably
>>>do this anyway?
>>
>>There is no rule in the safety or wiring standards that prevents you from
>>doing so,
>
>
>
> ** Of course there is !!
>
> A Class 2 appliance must not be earthed or it ceases to be one.
>
>
>
>
>>I read some of the other replies and would also like to add the following.
>>
>>1. There is no prohibition on interconection of Class 1 and Class 2
>>equipment.
>
>
>
>
> ** There is.
>
> A Class 2 appliance must not be earthed.
>

the prohibition on earthing class 2 appliances does not relate to
consumers plugging them into class 1 appliances, but to technical
personnel adding 3-pin plugs/wires.

as long as nobody fiddles with the mains connection, one is free to
earth as many inputs/outputs as one wishes.

Of course hooking the jacket of your video out RCA connector to, say,
Phase would be a fairly dangerous thing to do, but then so is poking a
knife into a toaster while its operating.

Phil Allison

unread,
Mar 23, 2006, 1:12:45 AM3/23/06
to

"Terry Given"


> the prohibition on earthing class 2 appliances does not relate to
> consumers plugging them into class 1 appliances,


** Yawn .......

A safety risk is created by so doing - possibly a very serious one.


....... Phil

Message has been deleted
Message has been deleted

Phil Allison

unread,
Mar 23, 2006, 2:32:27 AM3/23/06
to

"David, the pedantic FUCKWIT one.

>
>>
>> > There is no rule in the safety or wiring standards that prevents you
>> > from
>> > doing so,
>>
>>
>> ** Of course there is !!
>>
>> A Class 2 appliance must not be earthed or it ceases to be one.
>
>
> Definition and references below from AS/NZS60950-1, since I happen to be
> using
> it at the moment. Note the use of earthing is not prohibited, just that
> the
> safety strategy of the design must not rely on the protective earth.


** " No reliance " = NO connection to the AC supply earth system.


WAKE UP FUCKHEAD:

AS/NZ standards are for engineers and installers to heed.

The issue here relates to *ordinary consumers* !!!

Consumers are neither aware of nor need to follow published standards.

The law of **negligence** certainly applies to them though.


>> ** You are just making this crazy drivel up.
>>
>> The earthing requirements for a class 1 appliance relate to the copper
>> cross
>> section of the earth wire used, ie must not be not less than 1 sq mm. (
>> AS3100)
>

> 1.0 sq mm for 10A cords up to 2 metres long and 1.5 sq mm for 10A cords
> longer
> than 2 metres.


** Blah, blah, blah - same as I said.

Piss off - you damn IDIOT.

...... Phil


Terry Given

unread,
Mar 23, 2006, 3:15:04 AM3/23/06
to
David, not to be confused with the other Davids. wrote:
>>are you aware of any triple-insulated foils?
>>
>
>
> I haven't seen any (yet) that aren't of wrapped and folded insulation lay-up.
>
> The mandrel test for flexibility and adherence would pretty much exclude the
> use of other than round cross-sections in order to pass the 6 kV dielectric
> strength test (based on my experience to date, the edge of the foil would
> damage the layer(s) of extruded or spiral wrpped insulation).
>
> Now I have said this, I will probably see one tomorrow :-)
>
> High current devices using foil windings usually have very bulky concentric
> windings, since the insulation layup for each layer is sometimes as thick or
> thicker than the foil. Must be a right bugger to make them to even
> semi-precise tolerances.

Hi David,

I have used pre-fabricated kapton-wrapped foils, with IIRC 25um of
Kapton. These were incompletely wrapped - the insulation came in some
6mm on either side, thereby accomplishing the necessary creepages. I
used TIW for the primary. AIUI the trick with mfg these foils is to
treat the edges.... on a similar note, I built a 120A forward converter
(I forget Vout) for electroplating at Uni, and made the foil myself -
with scissors. I wrapped it with fiberglass tape, and man did the shitty
edges cause me grief. I had no real idea of what I was doing though, and
it took a long time to realise the secondary was shorted, and why. yay
for CMC though; despite being hand built on veroboard, no fires.

good stuff on the standards. There's not much point replying to Phil,
he's wrong and being abusive because you proved it quite conclusively.

Cheers
Terry

Phil Allison

unread,
Mar 23, 2006, 4:13:41 AM3/23/06
to

"Terry Given"

= Kiwi ARSEHOLE & MASSIVE BUCKET

" David, the pedantic FUCKWIT one."

> good stuff on the standards.


** Yawn - none of it had ANY relevance at all.

> There's not much point replying to Phil, he's wrong and being abusive
> because you proved it quite conclusively.


** WAKE UP - YOU ASININE FUCKHEADS:

AS/NZ standards are ONLY for engineers, manufacturers and installers to
heed !!

The potential shock hazard issue with class 2 and class items mixed in a
home entertainment system is all about what *ordinary consumers* do - at
home !!

Ordinary consumers are NOT aware of nor need to consider published standards
AT ALL !!

The laws of **negligence** certainly applies to them though.

Shame they does not apply to ANONYMOUS idiots posting dangerous CRAPOLOGY !

........ Phil


Alan Rutlidge

unread,
Mar 23, 2006, 5:40:06 AM3/23/06
to

"Terry Given" <my_...@ieee.org> wrote in message
news:1143093730.977482@ftpsrv1...

> Phil Allison wrote:
> Of course hooking the jacket of your video out RCA connector to, say,
> Phase would be a fairly dangerous thing to do, but then so is poking a
> knife into a toaster while its operating.

Well, you'd think Toaster Boi would know about that one. :P


Alan Rutlidge

unread,
Mar 23, 2006, 5:42:01 AM3/23/06
to

"Phil Allison" <phila...@tpg.com.au> wrote in message
news:48f186F...@individual.net...

>
> "David, the pedantic FUCKWIT one.

Shouldn't that read "David.......... won" ?

Phil lost....

Phil Allison

unread,
Mar 23, 2006, 6:06:57 AM3/23/06
to

"Alan Rutlidge" = The Rutmaniac Arse Bandit

See: http://www.advantra.net/contact_us.htm


The Rutmaniac Arse Bandit has **NEVER** told us how much money
that Thai pal he " imported " into Perth ripped off from his credit card
and bank accounts.

He has refused, over and over, to say why he never reported the crime his
Thai boy lover committed to his Bank or to the WA police.


** This post of his on " rec.travel asia " from Oct 11, 1997 explains the
event:

------------------------------­------------------------------­---


" WARNING - Tourism dangers for Gay Tourists in Thailand

In my case I was coerced into sponsoring a Thai into Australia. I was
lead down the garden path into a false sense of security about my
relationship with this person. His aim was clearly to get me to purswade
the Australian Embassy to grant him a visa. Once here I didn't exist after
he drained my bank account and ran my credit card into overdraft.


Alan Rutlidge (Perth Western Australia) "


----------------------------- ------------------------------------


** The 1997 date pretty much co-incidences with the enactment of
Section 50 BA of the Commonwealth Crimes Act.

This is the law that finally made engaging in or promoting under age
sex tourism a criminal offence - max penalty 17 years in jail.


BTW

The legal age of consent for gay males in WA in 1997 was 21 years old.


Come on - Arse Bandit - we all need to know if you were being
blackmailed.

BTW

I do not care how many of your vile, criminal colleagues you organise
to intimidate me.

It only makes you look so very much WORSE !!!

........ Phil

mdh...@iprimus.com.au

unread,
Mar 23, 2006, 6:45:05 AM3/23/06
to

If anyone wants to avoid all the agro here you're welcome over on Oz
Hi-Fi & HT :-

http://forum.aushifi.com/

.........a moderated forum that allows the posting of graphics, circuit
diagrams etc and avoids that flame wars that are destroying so many
newsgroups.

Phil Allison

unread,
Mar 23, 2006, 6:55:12 AM3/23/06
to

<mdh...@iprimus.com.au>


** Beware !!!!

The above halfwit is a female impersonator from northern Tasmania

Goes by the handle "Ayn Marx ".

Might as well be Groucho Marx !!!


> If anyone wants to avoid all the agro here you're welcome over on Oz
> Hi-Fi & HT :-

** ROTFL !!

A very recently set up chat room for fuckwit audiophools, moderated by
control freaks & psychopaths !!

Go for it dudes ......


....... Phil


Message has been deleted

Phil Allison

unread,
Mar 23, 2006, 7:05:29 AM3/23/06
to
Message has been deleted

Phil Allison

unread,
Mar 23, 2006, 7:11:59 AM3/23/06
to
Message has been deleted

Phil Allison

unread,
Mar 23, 2006, 7:16:16 AM3/23/06
to

Rob

unread,
Mar 23, 2006, 7:47:29 AM3/23/06
to
An interesting news article maybe.

"The dark side of the blogosphere was revealed by a libel action brought by
Michael Keith-Smith, a former Conservative party member who stood for Ukip
in Portsmouth North at the last election. He said he was moved to sue after
a woman with whom he was debating the merits of military action in Iraq
began a campaign of name-calling that started by describing him as "lard
brain" and culminated in falsely labelling him a "Nazi", a "racist bigot"
and a "nonce"."

http://technology.guardian.co.uk/news/story/0,,1737444,00.html

Yeah, I know kill-filing fixes most of the problem!


Alan Rutlidge

unread,
Mar 23, 2006, 9:12:36 AM3/23/06
to
Nice try Toaster Boi, but your OT reply only goes to demonstrate just how
much you have managed to loose the plot.
Face it, you lost the debate entirely due to your incompetence and pig
headedness, so you feel your only recourse is to try to shift the spotlight
off of your pitifulness in a vain attempt of distraction. Too bad Toaster
Boi - you lost again. :-)


"Phil Allison" <phila...@tpg.com.au> wrote in message

news:48fdqcF...@individual.net...

Terry Given

unread,
Mar 23, 2006, 9:30:48 AM3/23/06
to
Phil Allison wrote:
> "Terry Given"
>
> = Kiwi ARSEHOLE & MASSIVE BUCKET
>
> " David, the pedantic FUCKWIT one."
>
>
>>good stuff on the standards.
>
>
>
> ** Yawn - none of it had ANY relevance at all.
>
>
>
>
>>There's not much point replying to Phil, he's wrong and being abusive
>>because you proved it quite conclusively.
>
>
>
> ** WAKE UP - YOU ASININE FUCKHEADS:
>
> AS/NZ standards are ONLY for engineers, manufacturers and installers to
> heed !!

gee, here I was thinking its an electronics forum, where people come to
learn/share things about electronics. In which case a good hard look at
the relevant standards is excellent; few if any hobbyists get to see
these things, they are expensive.


>
> The potential shock hazard issue with class 2 and class items mixed in a
> home entertainment system is all about what *ordinary consumers* do - at
> home !!
>
> Ordinary consumers are NOT aware of nor need to consider published standards
> AT ALL !!
>
> The laws of **negligence** certainly applies to them though.

so what. its a moot point from an engineering perspective. These are the
same idiots that drive drunk, rob gas stations without covering their
faces etc, all of which are not just stupid and illegal, but criminal.


>
> Shame they does not apply to ANONYMOUS idiots posting dangerous CRAPOLOGY !
>
>
>
> ........ Phil

Cheers
Terry

Terry Given

unread,
Mar 23, 2006, 9:37:01 AM3/23/06
to

you'd think a towering intellect like Phil would realise that this is a
globally distributed public forum, and that anything libelous he writes
is likely to exist, if not forever then at least for a very long time.
eventually he's going to annoy someone who is happy to waste a bit of
money on lawyers

Cheers
Terry

Ray

unread,
Mar 23, 2006, 2:37:04 PM3/23/06
to
In article <1143116063....@u72g2000cwu.googlegroups.com>,
mdh...@iprimus.com.au says...

>
> If anyone wants to avoid all the agro here you're welcome over on Oz
> Hi-Fi & HT :-
> http://forum.aushifi.com/
> ........................a moderated forum that allows the posting of

> graphics, circuit
> diagrams etc and avoids that flame wars that are destroying so many
> newsgroups.
>
>

Hey fuckwit, who's the pot calling the kettle black?

Bloody Audiorasps creating flame wars themselves by starting agro. :(

The Real Andy

unread,
Mar 23, 2006, 4:28:17 PM3/23/06
to

I can faintly remember these behavioural traits from primary school

Jasen Betts

unread,
Mar 23, 2006, 6:02:25 AM3/23/06
to
On 2006-03-23, Phil Allison <phila...@tpg.com.au> wrote:
>
> "David, not to be confused with the other Davids."
>>
>>> Is there any rule that stops you earthing these devices, given that the
>>> connection via the signal leads to an earthed amp etc would probably
>>> do this anyway?
>>
>> There is no rule in the safety or wiring standards that prevents you from
>> doing so,
>
>
> ** Of course there is !!
>
> A Class 2 appliance must not be earthed or it ceases to be one.

And that would be a problem how?



>> I read some of the other replies and would also like to add the following.
>>
>> 1. There is no prohibition on interconection of Class 1 and Class 2
>> equipment.

> ** There is.
>
> A Class 2 appliance must not be earthed.

says you...

what's the deal with laplink cables ?

and connecting what's that bad thing that going to happen by connecting my
VCR and DVD player to my ancient TV (Phillips K9ii) which has an eathed
antenna connector. and my junk CD player (CD-rom drive in an old apple
external 5.25" enclosure with RCA sockets on the back) (earthed) is connected
to my cheap sterio.

--

Bye.
Jasen

Terry Given

unread,
Mar 23, 2006, 5:32:20 PM3/23/06
to

until the advent of usenet, the adult form was most commonly found in
parliament.

Cheers
Terry

Message has been deleted

mdh...@iprimus.com.au

unread,
Mar 23, 2006, 6:26:04 PM3/23/06
to

Starting agro ? ? ? You'd know it if I did.

Message has been deleted

Phil Allison

unread,
Mar 23, 2006, 7:57:58 PM3/23/06
to

"Jasen Betts" = just another anencephalic Kiwi

>> A Class 2 appliance must not be earthed or it ceases to be one.
>
> And that would be a problem how?


** Read the whole thread - FUCKWIT !


>> A Class 2 appliance must not be earthed.
>
> says you...


** My copy of AS 3100 says so as well.

" It will be apparent that double-insulated appliance built in accordance
with these principles must not be earthed."

It also says the "Double Insulated - Do Not Earth " warning is compulsory.

> and connecting what's that bad thing that going to happen by connecting my
> VCR and DVD player to my ancient TV (Phillips K9ii) which has an eathed
> antenna connector.


** If you actually ever learn to read one day, Jasen, it will be a
miracle.

" Earthed" = " mains earthed" = connected to the AC ground via a standard
3 pin plug and 3 pin outlet.


....... Phil


Phil Allison

unread,
Mar 23, 2006, 8:04:39 PM3/23/06
to

"Terry Given"
>
>> = Kiwi ARSEHOLE & MASSIVE FUCKWIT

>
>>
>> ** WAKE UP - YOU ASININE FUCKHEADS:
>>
>> AS/NZ standards are ONLY for engineers, manufacturers and installers to
>> heed !!
>
> gee, here I was thinking


** No sign of that in your posts - ever.

>> The potential shock hazard issue with class 2 and class items mixed in a
>> home entertainment system is all about what *ordinary consumers* do -
>> at home !!
>>
>> Ordinary consumers are NOT aware of nor need to consider published
>> standards AT ALL !!
>>
>> The laws of **negligence** certainly applies to them though.
>
> so what.


** Bad idea for them to do anything that is dangerous to others or for
anyone to encourage them to do it.


> its a moot point from an engineering perspective. These are the same
> idiots that drive drunk, rob gas stations without covering their faces
> etc, all of which are not just stupid and illegal, but criminal.


** That is just about the most asinine thing I have seen on this NG.

Terry Given = a rabid, psychotic, bloody lunatic.

I feel sorry for all those poor sheep.

......... Phil


Phil Allison

unread,
Mar 23, 2006, 8:12:14 PM3/23/06
to

"David, the TOTAL IDIOT "


>> ** WAKE UP - YOU ASININE FUCKHEADS:
>>
>> AS/NZ standards are ONLY for engineers, manufacturers and installers to
>> heed !!

>> Ordinary consumers are NOT aware of nor need to consider published
>> standards
>> AT ALL !!
>>
>> The laws of **negligence** certainly applies to them though.
>>
>> Shame they does not apply to ANONYMOUS idiots posting
>> dangerous CRAPOLOGY !
>

> I believe it does.


** The "anonymous" bit would be a problem - FUCKWIT !!

> Negligence has to be proven. Way too complicated for this discussion.


** It is the whole basis of the matter - you ASS.

>> The potential shock hazard issue with class 2 and class items mixed in a
>> home entertainment system is all about what *ordinary consumers* do -
>> at
>> home !!
>

> I am going to wind this back to the OPs point about earthing the
> enclosure,


** Wrong issue.

That is another matter.


........ Phil


Malcolm Moore

unread,
Mar 23, 2006, 9:39:32 PM3/23/06
to
On Fri, 24 Mar 2006 11:57:58 +1100, "Phil Allison"
<phila...@tpg.com.au> wrote:

>
>"Jasen Betts" = just another anencephalic Kiwi
>

snip

>>> A Class 2 appliance must not be earthed.
>>
>> says you...
>
>
>** My copy of AS 3100 says so as well.
>
>" It will be apparent that double-insulated appliance built in accordance
>with these principles must not be earthed."
>
>It also says the "Double Insulated - Do Not Earth " warning is compulsory.


In a reply to my post just yesterday you stated

---------------------------------
** The warning notice is not compulsory.
"Only the use of the "double square" symbol or the words "Double
Insulated" are. "
---------------------------------

AS/NZS 3100 is not the applicable standard for domestic entertainment
equipment. It is used for equipment that does not have a specific
standard.

AS/NZS 60065:2000
Audio, video and similar electronic
apparatus-Safety requirements
(IEC 60065:1998 MOD)

is the appropriate standard for this discussion.


snip
--
Regards
Malcolm
Remove sharp objects to get a valid e-mail address

Phil Allison

unread,
Mar 23, 2006, 10:02:29 PM3/23/06
to

"Malcolm Moore"

>>>> A Class 2 appliance must not be earthed.
>>>
>>> says you...
>>
>>
>>** My copy of AS 3100 says so as well.
>>

>>" It will be apparent that double-insulated appliances built in accordance


>>with these principles must not be earthed."
>>
>>It also says the "Double Insulated - Do Not Earth " warning is compulsory.
>
>
> In a reply to my post just yesterday you stated
>
> ---------------------------------
> ** The warning notice is not compulsory.
> "Only the use of the "double square" symbol or the words "Double
> Insulated" are. "
> ---------------------------------


** So ?


You made NO reply to the other answers I so thoughtfully gave you.


Class 2 construction appliances are inherently much safer than class 1
types.

What users do that COMPROMISES that additional safety is beyond the control
of makers or authorities.

The issue is one of legal liability on the part of someone who elects to
earth a class 2 item .

In some cases, doing that would be equivalent to murder.


........ Phil

The Real Andy

unread,
Mar 24, 2006, 4:01:35 AM3/24/06
to
On Thu, 23 Mar 2006 23:23:25 GMT, GB <g...@sonicresearch.mailme.org>
wrote:

>Jasen Betts <ja...@free.net.nz> wrote in
>news:7df9.4422...@clunker.homenet:

>> what's the deal with laplink cables ?
>

> If the connector shells at each end are connected together, they
>can connect the frame earth of the two devices. Not always a good
>thing.

But, if the device is double insulated, then wont the exposed frames
be doubly isolated from the mains earth? IS this not why you get the
tingle? the whole frame is floating about mains earth because it is
not connected to mains earth.

Or perhaps I am wrong. Perhaps there is a secret earth connection to
double insultated gear that the manufacturers just accidently forgot
to tell people about. Perhaps the manufacturers decided to make you
mains earth magically float up. Or perhpas they just built in some
electric shocking mechanism for fun.

I remember daealing with a sparky when i was a 1st year apprentice. He
just couldn't figure out why, that if i was not connected to mains
earth or to neutral i could touch active and not get electrocuted. I
even gave him personal proof once. I then got a multimeter and put one
probe in active, and the other in the air, and asked him why it did
not give any significant reading, until i stuck the other probe in
neutral or earth. He still did not get it.

It all stemmed from the discussion of the use of isolation
transformers..

>G

The Real Andy

unread,
Mar 24, 2006, 4:13:42 AM3/24/06
to
On Fri, 24 Mar 2006 10:32:20 +1200, Terry Given <my_...@ieee.org>
wrote:

more frequently in mental institutions.


>
>Cheers
>Terry

Jasen Betts

unread,
Mar 24, 2006, 3:34:02 AM3/24/06
to
On 2006-03-23, Phil Allison <phila...@tpg.com.au> wrote:
><mdh...@iprimus.com.au>

>> If anyone wants to avoid all the agro here you're welcome over on Oz


>> Hi-Fi & HT :-
>
> ** ROTFL !!
>
> A very recently set up chat room for fuckwit audiophools, moderated by
> control freaks & psychopaths !!

Tranlation: Philthy isn't allowed in.


Bye.
Jasen

Phil Allison

unread,
Mar 24, 2006, 6:30:54 AM3/24/06
to

"Jasen Bleats" = Kiwi sheep fucker

** Even NZ sheep wont let this PITC in.


........ Phil

Jasen Betts

unread,
Mar 24, 2006, 5:48:57 AM3/24/06
to
On 2006-03-24, Phil Allison <phila...@tpg.com.au> wrote:
>
> "Jasen Betts" = just another anencephalic Kiwi
>
>>> A Class 2 appliance must not be earthed or it ceases to be one.
>>
>> And that would be a problem how?
>
> ** Read the whole thread - FUCKWIT !

you explained how connecting a class two appliance to a live conductor could
be dangerous, I didn't see any explanation of how earthing the appliance was
bad. (except earth loops)

>>> A Class 2 appliance must not be earthed.
>>
>> says you...
>
> ** My copy of AS 3100 says so as well.
>
> " It will be apparent that double-insulated appliance built in accordance
> with these principles must not be earthed."

that seems odd, perhaps because it's taken out of context.

> It also says the "Double Insulated - Do Not Earth " warning is compulsory.

it must be wrong then... I see many devices with the double squares but no
"do not earth"

>> and connecting what's that bad thing that going to happen by connecting my
>> VCR and DVD player to my ancient TV (Phillips K9ii) which has an eathed
>> antenna connector.
>
> ** If you actually ever learn to read one day, Jasen, it will be a
> miracle.
>
> " Earthed" = " mains earthed" = connected to the AC ground via a standard
> 3 pin plug and 3 pin outlet.

I know how to read an ohmmeter and it tells me the outer conductor of the
anterena socket is conneted to the earth pin on the mains lead.

If you don't believe me you can come over here aand measure it or dig up a
schematic somewhere, the K9 was once quite common.

Bye.
Jasen

Rob

unread,
Mar 24, 2006, 7:32:46 AM3/24/06
to

"Terry Given" <my_...@ieee.org> wrote in message
news:1143124458.155750@ftpsrv1...


Hey - perhaps lawyers aren't so bad after all!

Phil Allison

unread,
Mar 24, 2006, 7:42:11 AM3/24/06
to

"Jasen Bleats"


= just another anencephalic sheep FUCKING Kiwi MORON


>> ** Read the whole thread - FUCKWIT !
>
> you explained how connecting a class two appliance to a live conductor
> could
> be dangerous,


** Find those words from me and post them.

Or go back to rooting pregnant sheep.


>> It also says the "Double Insulated - Do Not Earth " warning is
>> compulsory.
>
> it must be wrong then..


** No.


........ Phil


Chris Jones

unread,
Mar 24, 2006, 11:56:15 AM3/24/06
to
Phil Allison wrote:

>
> "Chris Jones"
>>
> >
>>> ** Do you constantly move the goalposts at sporting events too ?
>>>
>>
>> I don't consider posting to usenet to be a competition,
>
>
> ** Then why keep moving the goal posts like is is one you cannot bear to
> loose ??

When I change the topic, it has not been with the intention of winning or
avoiding "loosing" (or even losing) an argument. I don't like being wrong
but the only way around that is to learn more. If I think I have nothing
to add on a particular topic then I don't write anything about it. If it
leads me to think about a different topic that interests me then I will ask
or comment about that. You have posted some thought-provoking replies and
I thank you for that. I know more than I used to about a couple of things.

>> I just like to learn stuff.
>
>
> ** If you mean that, then why make it impossible for anyone to answer you
> ?
>
I think you have managed ok.

Malcolm Moore

unread,
Mar 24, 2006, 5:09:03 PM3/24/06
to
On Thu, 23 Mar 2006 12:05:21 +1100, "Phil Allison"
<phila...@tpg.com.au> wrote:

>
>"Malcolm Moore"
> "Phil Allison"
>
>>>
>>>** Have you never seen the words " Double Insulated - Do Not Earth " on
>>>the back of a class 2 item ??
>>>
>>> Pretty clear isn't it?
>>
>> I've just checked all the double insulated items in my home and NONE
>> of them carry a warning such as you describe.


>
>
>** The warning notice is not compulsory.
>
>Only the use of the "double square" symbol or the words "Double Insulated"
>are.
>
>

>>The matter is very much an *X rated topic * in the home entertainment
>>>electronics industry.
>>
>> So where does the "PROHIBITION" come from?
>
>
>** The fact that a class 2 appliance must not be earthed.
>
>
>> Previously you said such interconnection was prohibited, now you're
>> saying to ignore the issue??
>
>
>** Huh ???
>
> What madman's logic is this ?
>
> What the hell do you think "X -rated " means ???

Fair comment. You have chosen to delete part of your previous post to
which I was replying. I'll put it back in.

>Equipment makers are not liable for what users may WRONGLY do when
>interconnecting items of gear - so just ignore the issue.
>
>
>
>The matter is very much an *X rated topic * in the home entertainment
>electronics industry.

Your use of a hyphen before "so just ignore the issue." led me to
believe that was your view. On reading it again I realise you were
attributing that to the manufacturers. That sentence would have been
clearer with a comma or even no punctuation there.
My apologies for misunderstanding.


>>>** Imagine a hi-fi system with every item in it class 2 - so there is no
>>>AC
>>>ground to the metalwork.
>>>
>>>Next, an item is added to the system, ie a nice old valve tuner just
>>>bought
>>>from Ebay but with no AC plug.
>>>
>>>Next, the user inadvertently wires up the new plug wrongly with active and
>>>earth reversed and makes all the connections.
>>>
>>>The hi-fi system will still work just as before ( but not the tuner) but
>>>with ALL the metalwork, connecting leads and even the loud speakers now
>>>LIVE !!!
>>>
>>>In countries with 240 volt AC power, this is a FATAL accident scenario
>>>!!!!
>>
>>
>> If this danger was significant then the use of Class 2 equipment is
>> inherently unsafe because it would be relying on user action to make
>> it safe, the user action being to not interconnect with other commonly
>> available items.
>
>
>** Absolute drivel.


>
>Class 2 construction appliances are inherently much safer than class 1
>types.
>
>What users do that COMPROMISES that additional safety is beyond the control
>of makers or authorities.
>

>>As you say above, "Equipment makers are not liable
>> for what users may WRONGLY do.....", but regulators are always
>> interested in such things. They seem relaxed about the situation.
>
>
>** SFA they can do about it.

Which is exactly why there is no prohibition on interconnecting
earthed and double insulated home entertainment equipment.

>The issue is one of legal liability on the part of someone who elects to
>earth a class 2 item.

As in my other post, the legal liability arises from miswiring a plug,
not from interconecting different classes of equipment.

Malcolm Moore

unread,
Mar 24, 2006, 5:09:25 PM3/24/06
to
On Fri, 24 Mar 2006 14:02:29 +1100, "Phil Allison"
<phila...@tpg.com.au> wrote:

>
>"Malcolm Moore"
>
>>>>> A Class 2 appliance must not be earthed.
>>>>
>>>> says you...
>>>
>>>
>>>** My copy of AS 3100 says so as well.
>>>
>>>" It will be apparent that double-insulated appliances built in accordance
>>>with these principles must not be earthed."
>>>
>>>It also says the "Double Insulated - Do Not Earth " warning is compulsory.
>>
>>
>> In a reply to my post just yesterday you stated
>>
>> ---------------------------------
>> ** The warning notice is not compulsory.
>> "Only the use of the "double square" symbol or the words "Double
>> Insulated" are. "
>> ---------------------------------
>
>
>** So ?

So you have contradicted yourself in quoting from the Standard you are
relying upon. Hardly the tactic to use to convince people of your
position on this matter.

Your use of the title AS 3100 perhaps indicates you are relying on an
old version, it has been AS/NZS 3100 since at least 2002 when the
ccurrent version was promulgated.

>You made NO reply to the other answers I so thoughtfully gave you.

I have rectified this in another post.

>Class 2 construction appliances are inherently much safer than class 1
>types.
>
>What users do that COMPROMISES that additional safety is beyond the control
>of makers or authorities.
>
>The issue is one of legal liability on the part of someone who elects to
>earth a class 2 item .

No. The issue is one of legal liability on the part of someone who
elects to miswire the plug on a Class 1 item, with phase and earth
swapped, and then doesn't do required testing before it is placed in
service. The equipment would be just as dangerous if it were used
stand alone.

>In some cases, doing that would be equivalent to murder.

In most jurisdictions that would be manslaughter or culpable homicide
or similar. Still a serious charge.

Jasen Betts

unread,
Mar 24, 2006, 4:11:05 PM3/24/06
to
On 2006-03-24, The Real Andy <will_get_back_to_you_on_This@> wrote:
> On Thu, 23 Mar 2006 23:23:25 GMT, GB <g...@sonicresearch.mailme.org>
> wrote:
>
>>Jasen Betts <ja...@free.net.nz> wrote in
>>news:7df9.4422...@clunker.homenet:
>>> what's the deal with laplink cables ?
>>
>> If the connector shells at each end are connected together, they
>>can connect the frame earth of the two devices. Not always a good
>>thing.
>
> But, if the device is double insulated, then wont the exposed frames
> be doubly isolated from the mains earth? IS this not why you get the
> tingle? the whole frame is floating about mains earth because it is
> not connected to mains earth.

To be honest, I hadn't considered the possibility that the serial port might
be isolated from the circuitry inside the laptop.

this one isn't.

Bye.
Jasen