Anyone know how they run the mains in Tenerife?

Apart from the obvious answer - "without much care" that is...

Seems there is no earth and my laptop is giving me regular shocks when
I touch some of the metal connectors - e.g. the extrnal VGA socket and
the audio sockets. Not big shocks, but enough to irritate.

My laptop's power supply is the usual little "brick" device - 3-pin
cloverleaf input, 19v output...

I'm told (by some of my family who live here) that "that's the way it is",
but I can't help thinking that maybe it could be better!

Cheers,

Gordon

Well I doubt its the fault of the mains, sounds to me like there might be a
fault with the brick.

Brian

--
From the Sofa of Brian Gaff Reply address is active
"Gordon Henderson" wrote in message
...
Anyone know how they run the mains in Tenerife?

Apart from the obvious answer - "without much care" that is...

Seems there is no earth and my laptop is giving me regular shocks when
I touch some of the metal connectors - e.g. the extrnal VGA socket and
the audio sockets. Not big shocks, but enough to irritate.

My laptop's power supply is the usual little "brick" device - 3-pin
cloverleaf input, 19v output...

I'm told (by some of my family who live here) that "that's the way it is",
but I can't help thinking that maybe it could be better!

Cheers,

Gordon

On 11/10/2012 10:27, Gordon Henderson wrote:
Anyone know how they run the mains in Tenerife?

Apart from the obvious answer - "without much care" that is...

Seems there is no earth and my laptop is giving me regular shocks when
I touch some of the metal connectors - e.g. the extrnal VGA socket and
the audio sockets. Not big shocks, but enough to irritate.

My laptop's power supply is the usual little "brick" device - 3-pin
cloverleaf input, 19v output...

Does your brick have the double isolated symbol on it?
Looks like two concentric squares ASCII art
_____
| _ |
| |_| |
|_____|

I am guessing not and that with a non-polarised plug it is luck of the
draw whether your laptop is sat at neutral + 19v or line voltage - 19v.

If it bothers you you might want to get one that is double isolated.

I'm told (by some of my family who live here) that "that's the way it is",
but I can't help thinking that maybe it could be better!

There must be some earth path otherwise you wouldn't feel it.

--
Regards,
Martin Brown

In article ,
Martin Brown wrote:
On 11/10/2012 10:27, Gordon Henderson wrote:
Anyone know how they run the mains in Tenerife?

Apart from the obvious answer - "without much care" that is...

Seems there is no earth and my laptop is giving me regular shocks when
I touch some of the metal connectors - e.g. the extrnal VGA socket and
the audio sockets. Not big shocks, but enough to irritate.

My laptop's power supply is the usual little "brick" device - 3-pin
cloverleaf input, 19v output...

Does your brick have the double isolated symbol on it?
Looks like two concentric squares ASCII art
_____
| _ |
| |_| |
|_____|

No.

I am guessing not and that with a non-polarised plug it is luck of the
draw whether your laptop is sat at neutral + 19v or line voltage - 19v.

If it bothers you you might want to get one that is double isolated.

Might do for next time I'm out here.

I'm told (by some of my family who live here) that "that's the way it is",
but I can't help thinking that maybe it could be better!

There must be some earth path otherwise you wouldn't feel it.

That's my thought too - but everything is sort of hot & sticky and feels
damp here - although it's not that high a humidity.

I am quite bemused by their seemingly lax attitide to it all - power
sockets in the bathroom, etc.

Oh well... Flying home tomorrow...

Gordon

I'd have thought that all current bricks sold in the UK or indeed Europe are
double isolated. However often they have capacitors inside to stop
interference and these can give the impression of tingly shocks. Of course
they could be faulty so its best to be careful. If you are really worried
earth the metal bits of the computer before plugging into the mains with a
wire. I'm surprised any metal bits protrude though, many seem to have
plastic even on the jackscrew holes these days, and most so called metal
cases are in fact mostly plastic with metal glued over the top.


These canpick up tingles but are not usually dangerous unless connected to
something inside.
Brian

--
Brian Gaff....Note, this account does not accept Bcc: email.
graphics are great, but the blind can't hear them
Email:
__________________________________________________ __________________________________________________ __________


"Martin Brown" wrote in message
...
On 11/10/2012 10:27, Gordon Henderson wrote:
Anyone know how they run the mains in Tenerife?

Apart from the obvious answer - "without much care" that is...

Seems there is no earth and my laptop is giving me regular shocks when
I touch some of the metal connectors - e.g. the extrnal VGA socket and
the audio sockets. Not big shocks, but enough to irritate.

My laptop's power supply is the usual little "brick" device - 3-pin
cloverleaf input, 19v output...

Does your brick have the double isolated symbol on it?
Looks like two concentric squares ASCII art
_____
| _ |
| |_| |
|_____|

I am guessing not and that with a non-polarised plug it is luck of the
draw whether your laptop is sat at neutral + 19v or line voltage - 19v.

If it bothers you you might want to get one that is double isolated.

I'm told (by some of my family who live here) that "that's the way it
is",
but I can't help thinking that maybe it could be better!

There must be some earth path otherwise you wouldn't feel it.

--
Regards,
Martin Brown

On 11/10/2012 11:31, Brian Gaff wrote:
I'd have thought that all current bricks sold in the UK or indeed Europe are
double isolated. However often they have capacitors inside to stop
interference and these can give the impression of tingly shocks. Of course

I thought that too, but the first one I picked up here wasn't!

they could be faulty so its best to be careful. If you are really worried
earth the metal bits of the computer before plugging into the mains with a
wire. I'm surprised any metal bits protrude though, many seem to have
plastic even on the jackscrew holes these days, and most so called metal
cases are in fact mostly plastic with metal glued over the top.


These canpick up tingles but are not usually dangerous unless connected to
something inside.
Brian

It does provide interesting modes of failure for metal chassis mains
powered PCs in countries with flaky earth and two pin sockets.

--
Regards,
Martin Brown

Yes, but I thought it was actually illegal to supply non double insulated
psus here now?
Is this yet another non policed thing like most things these days.

Brian

--
Brian Gaff....Note, this account does not accept Bcc: email.
graphics are great, but the blind can't hear them
Email:
__________________________________________________ __________________________________________________ __________


"Martin Brown" wrote in message
...
On 11/10/2012 11:31, Brian Gaff wrote:
I'd have thought that all current bricks sold in the UK or indeed Europe
are
double isolated. However often they have capacitors inside to stop
interference and these can give the impression of tingly shocks. Of
course

I thought that too, but the first one I picked up here wasn't!

they could be faulty so its best to be careful. If you are really worried
earth the metal bits of the computer before plugging into the mains with
a
wire. I'm surprised any metal bits protrude though, many seem to have
plastic even on the jackscrew holes these days, and most so called metal
cases are in fact mostly plastic with metal glued over the top.


These canpick up tingles but are not usually dangerous unless connected
to
something inside.
Brian

It does provide interesting modes of failure for metal chassis mains
powered PCs in countries with flaky earth and two pin sockets.

--
Regards,
Martin Brown

In article ,
Brian Gaff wrote:
Yes, but I thought it was actually illegal to supply non double insulated
psus here now?
Is this yet another non policed thing like most things these days.

My Laptop is some 4 years old now, so who knows. Surprisedi it had the
cloverleaf connected rather than the figure-8 type.

As for connecting it to an earth... Somewhat challenging as there is no earth.

Not in the sockets anyway.

Gordon

On Thursday, October 11, 2012 11:17:53 AM UTC+1, Martin Brown wrote:

with a non-polarised plug it is luck of the
draw whether your laptop is sat at neutral + 19v or line voltage - 19v.

Not all countries supply line and neutral to the socket. In Norway, for example, every house gets all three phases but no neutral. Each socket in the house is wired across two of the phases with different rooms on different pairs of phases.

Robert

On Thursday, October 11, 2012 11:26:55 AM UTC+1, Gordon Henderson wrote:

I am quite bemused by their seemingly lax attitide to it all - power
sockets in the bathroom, etc.

When i vist my in-laws in Romania I always insist on unplugging the electric fire that stands beside the bath and which is usually plugged into a sucket conveniently located within reach of the bather.

They think I am a fuss-pot.

Robert

In message , Gordon Henderson
writes

My Laptop is some 4 years old now, so who knows. Surprisedi it had the
cloverleaf connected rather than the figure-8 type.

My most recent Lenovo Thinkpad has over 20 different what look like
safety marks on the power supply, but no two square boxes inside each
other.

The amazingly cheap Chinese replacement power supply that I'm using on
this older Lenovo, but which was sold as suitable for either machine
does have the square boxes.

Both have clover leaf mains leads.
--
Bill

On Thu, 11 Oct 2012 11:12:59 +0000 (UTC), Gordon Henderson
wrote:

In article ,
Brian Gaff wrote:
Yes, but I thought it was actually illegal to supply non double insulated
psus here now?
Is this yet another non policed thing like most things these days.

My Laptop is some 4 years old now, so who knows. Surprisedi it had the
cloverleaf connected rather than the figure-8 type.

As for connecting it to an earth... Somewhat challenging as there is no earth.

Take some in a milk bottle next time you go out. ;-)

Not in the sockets anyway.

DerekG

On 11/10/2012 12:30, Bill wrote:
In message , Gordon Henderson
writes

My Laptop is some 4 years old now, so who knows. Surprisedi it had the
cloverleaf connected rather than the figure-8 type.

My most recent Lenovo Thinkpad has over 20 different what look like
safety marks on the power supply, but no two square boxes inside each
other.

The amazingly cheap Chinese replacement power supply that I'm using on
this older Lenovo, but which was sold as suitable for either machine
does have the square boxes.

Both have clover leaf mains leads.

These days you also need a jewellers' loupe to be able to read the
minuscule details on the postage stamp sized ratings sticker.

--
Regards,
Martin Brown

On Thu, 11 Oct 2012 12:33:38 +0100, DerekG wrote:

On Thu, 11 Oct 2012 11:12:59 +0000 (UTC), Gordon Henderson
wrote:

In article ,
Brian Gaff wrote:
Yes, but I thought it was actually illegal to supply non double insulated
psus here now?
Is this yet another non policed thing like most things these days.

My Laptop is some 4 years old now, so who knows. Surprisedi it had the
cloverleaf connected rather than the figure-8 type.

As for connecting it to an earth... Somewhat challenging as there is no earth.

Take some in a milk bottle next time you go out. ;-)

Won't be allowed to be taken on the plane.
Having earth on board would be a huge danger to the plane if it flew through a
thunderstorm. ;-)



--
Regards, Paul Herber, Sandrila Ltd.
http://www.sandrila.co.uk/

On 11/10/2012 12:45, Paul Herber wrote:
On Thu, 11 Oct 2012 12:33:38 +0100, wrote:

On Thu, 11 Oct 2012 11:12:59 +0000 (UTC), Gordon Henderson
wrote:

In ,
Brian wrote:
Yes, but I thought it was actually illegal to supply non double insulated
psus here now?
Is this yet another non policed thing like most things these days.

My Laptop is some 4 years old now, so who knows. Surprisedi it had the
cloverleaf connected rather than the figure-8 type.

As for connecting it to an earth... Somewhat challenging as there is no earth.

Take some in a milk bottle next time you go out. ;-)

Won't be allowed to be taken on the plane.
Having earth on board would be a huge danger to the plane if it flew through a
thunderstorm. ;-)



Back to the old elements:

Earth + Air + Fire = Water

--
Rod

On 11/10/2012 12:14, RobertL wrote:
On Thursday, October 11, 2012 11:17:53 AM UTC+1, Martin Brown wrote:

with a non-polarised plug it is luck of the
draw whether your laptop is sat at neutral + 19v or line voltage - 19v.

Not all countries supply line and neutral to the socket. In Norway, for example, every house gets all three phases but no neutral. Each socket in the house is wired across two of the phases with different rooms on different pairs of phases.

Robert




So Norway have 400 (440?) volt mains?

On Thursday, October 11, 2012 1:48:39 PM UTC+1, Phil wrote:
On 11/10/2012 12:14, RobertL wrote: On Thursday, October 11, 2012 11:17:53 AM UTC+1, Martin Brown wrote: with a non-polarised plug it is luck of the draw whether your laptop is sat at neutral + 19v or line voltage - 19v. Not all countries supply line and neutral to the socket. In Norway, for example, every house gets all three phases but no neutral. Each socket in the house is wired across two of the phases with different rooms on different pairs of phases. Robert

So Norway have 400 (440?) volt mains?

No, they have 230 Volts between each pair of phases, so the sockets are '230Volt' sockets. It means, I think, 132Volts (=115*sin(60)) Volts between any mains wire and earth - which is considered safer than having 230 Volts between some wires and earth as we do in the UK.

Robert

....and in Japan they have 100 VOlts (using line and neutral) at 50Hz in the west of the country and 60Hz in the east.

Robert

On Thu, 11 Oct 2012 13:48:38 +0100, Phil wrote:

So Norway have 400 (440?) volt mains?

No, their three phase is Delta rather than Star connected,
hence the lack of a Neutral connection. I found that out
when fixing a problem with a three phase powered disk
motor... (the disk was the size of a large washing machine)

--
John W

En el artículo , Gordon Henderson
escribió:

I am quite bemused by their seemingly lax attitide to it all

indeed.

Playa del Inglés, Gran Canaria, April 2011:

http://jasper.org.uk/dodgy_lectrics

this was at knee height on a busy side street in an area with a lot of
kids about. It was live. Covered up a couple of days later.

Never did find out if someone got fried.

--
(\_/)
(='.'=)
(")_(")

En el artículo , Gordon Henderson
escribió:

As for connecting it to an earth... Somewhat challenging as there is no earth.

No problemo Señor!

http://jasper.org.uk/its_earthed.jpg

--
(\_/)
(='.'=)
(")_(")

"Mike Tomlinson" wrote in message ...

En el artículo , Gordon Henderson
escribió:

I am quite bemused by their seemingly lax attitide to it all

indeed.

Playa del Inglés, Gran Canaria, April 2011:

http://jasper.org.uk/dodgy_lectrics

this was at knee height on a busy side street in an area with a lot of
kids about. It was live. Covered up a couple of days later.

Never did find out if someone got fried.


What the problem - they have fuses AND they're CE marked G

AWEM

Which is why I'm surprised it makes any difference which way around the
mains is connected unless the brick is faulty, which is where we came in.

I can recall their mains ovetr there not only having no earth most of the
time but being very unreliable as well. One good thunderstorm and a three
hour power cut!

I love the way people just use poke in the socket with bare wires with
sticky tape technology as well...
Brian

--
From the Sofa of Brian Gaff Reply address is active
"Gordon Henderson" wrote in message
...
In article ,
Brian Gaff wrote:
Yes, but I thought it was actually illegal to supply non double insulated
psus here now?
Is this yet another non policed thing like most things these days.

My Laptop is some 4 years old now, so who knows. Surprisedi it had the
cloverleaf connected rather than the figure-8 type.

As for connecting it to an earth... Somewhat challenging as there is no
earth.

Not in the sockets anyway.

Gordon

On 11/10/2012 19:17, Brian Gaff wrote:

Which is why I'm surprised it makes any difference which way around the
mains is connected unless the brick is faulty, which is where we came in.

I thought this one had been done a few weeks back...

The usual setup seems to be that the neutral to the laptop is also
connected to the earth on the mains input. Hence with no earth this is
left floating. The mains input additionally will have suppression
filters that capacitively link L to E and N to E. Hence without the E
being connected, it will tend to float at half mains, and thus the metal
bits of the laptop do as well. Its not dangerous since the current you
can draw through the suppression filter is tidy, but its enough to give
the irritating tingle.


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On Thu, 11 Oct 2012 20:26:34 +0100, John Rumm
wrote:

On 11/10/2012 19:17, Brian Gaff wrote:

Which is why I'm surprised it makes any difference which way around the
mains is connected unless the brick is faulty, which is where we came in.

I thought this one had been done a few weeks back...

The usual setup seems to be that the neutral

ITYM chassis

to the laptop is also
connected to the earth on the mains input. Hence with no earth this is
left floating. The mains input additionally will have suppression
filters that capacitively link L to E and N to E. Hence without the E
being connected, it will tend to float at half mains, and thus the metal
bits of the laptop do as well. Its not dangerous since the current you
can draw through the suppression filter is tidy, but its enough to give
the irritating tingle.

Not only confined to laptops, seen the same with sat receivers, tv's and and
freeview boxes.


--

On 11/10/2012 22:45, The Other Mike wrote:
On Thu, 11 Oct 2012 20:26:34 +0100, John Rumm
wrote:

On 11/10/2012 19:17, Brian Gaff wrote:

Which is why I'm surprised it makes any difference which way around the
mains is connected unless the brick is faulty, which is where we came in.

I thought this one had been done a few weeks back...

The usual setup seems to be that the neutral

ITYM chassis

Indirectly yes - but if there are only two wires to the laptop, and one
is the neutral, then that is also what gets connected to chassis.

to the laptop is also
connected to the earth on the mains input. Hence with no earth this is
left floating. The mains input additionally will have suppression
filters that capacitively link L to E and N to E. Hence without the E
being connected, it will tend to float at half mains, and thus the metal
bits of the laptop do as well. Its not dangerous since the current you
can draw through the suppression filter is tidy, but its enough to give
the irritating tingle.

Not only confined to laptops, seen the same with sat receivers, tv's and and
freeview boxes.

Yup loads of stuff. I noticed it on a hi-fi amp once where the house
earthing was TT - the high Ze left enough voltage on the case that you
could feel it when you brushed your fingers over it.

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On Thu, 11 Oct 2012 17:45:26 +0100, Mike Tomlinson wrote:

En el artÃ*culo , Gordon Henderson
escribió:

I am quite bemused by their seemingly lax attitide to it all

indeed.

Playa del Inglés, Gran Canaria, April 2011:

http://jasper.org.uk/dodgy_lectrics

this was at knee height on a busy side street in an area with a lot of
kids about. It was live. Covered up a couple of days later.

The previous owners of our place had put a fusebox - of likely similar
vintage to that one - in one of the bathrooms, on the wall at the far end
of the bath/shower (or more likely, the fusebox was there first and the
room was converted to a bathroom later, but they didn't see the need to
relocate the box). It had a home-made plywood cover, held in place by
friction alone...

Electrics here in the US are seriously dodgy!

cheers

Jules

On 11/10/2012 23:28, John Rumm wrote:
On 11/10/2012 22:45, The Other Mike wrote:
On Thu, 11 Oct 2012 20:26:34 +0100, John Rumm

wrote:

On 11/10/2012 19:17, Brian Gaff wrote:

Which is why I'm surprised it makes any difference which way around the
mains is connected unless the brick is faulty, which is where we
came in.

I thought this one had been done a few weeks back...

The usual setup seems to be that the neutral

ITYM chassis

Indirectly yes - but if there are only two wires to the laptop, and one
is the neutral, then that is also what gets connected to chassis.

Only if you want to die. Figure of 8 two pin cables are non polarised.
If the laptop is on a two wire connector then the PSU must be double
isolated or you have a 50:50 chance of having a live chassis.

Live chassis was the default for old tube based TV sets internally. They
were wooden on the outside and had many other much more deadly voltages
lurking about inside with the cover off.

to the laptop is also
connected to the earth on the mains input. Hence with no earth this is
left floating. The mains input additionally will have suppression
filters that capacitively link L to E and N to E. Hence without the E
being connected, it will tend to float at half mains, and thus the metal
bits of the laptop do as well. Its not dangerous since the current you
can draw through the suppression filter is tidy, but its enough to give
the irritating tingle.

Correct. That is sort of OK provided the filter capacitors never fail.

Not only confined to laptops, seen the same with sat receivers, tv's
and and
freeview boxes.

Yup loads of stuff. I noticed it on a hi-fi amp once where the house
earthing was TT - the high Ze left enough voltage on the case that you
could feel it when you brushed your fingers over it.

Bad or no earth and input filters leaves the notionally earthed chassis
floating somewhere midway between live and neutral. This is OK until one
or other of the filter capacitors fails short circuit (rare but not
unknown). There is a very good reason why the ratings plates on things
with an external metal chassis says "this appliance must be earthed".

Carrying a neon screwdriver on holiday is not a bad idea. It doesn't
hurt as much when you find for example a live anglepoise lamp (I did).

--
Regards,
Martin Brown

In article , Jules Richardson jules.richard
writes

Electrics here in the US are seriously dodgy!

Especially if it's knob-and-tube (still in widespread use) or aluminium*
wiring.

* this is a UK group with UK English spelling, dammit.

--
(\_/)
(='.'=)
(")_(")

In article ,

RobertL wrote:

On Thursday, October 11, 2012 1:48:39 PM UTC+1, Phil wrote:
On 11/10/2012 12:14, RobertL wrote: On Thursday, October 11, 2012
11:17:53 AM UTC+1, Martin Brown wrote: with a non-polarised plug it is
luck of the draw whether your laptop is sat at neutral + 19v or line
voltage - 19v. Not all countries supply line and neutral to the socket.
In Norway, for example, every house gets all three phases but no neutral.
Each socket in the house is wired across two of the phases with different
rooms on different pairs of phases. Robert

So Norway have 400 (440?) volt mains?

No, they have 230 Volts between each pair of phases, so the sockets are

'230Volt' sockets. It means, I think, 132Volts (=115*sin(60)) Volts ...

%This can't be right as sin(60) = 0.866 approx i.e. less than 1.0 you
prolly meant 115/sin(60).

yes sorry, I did mean that. Robert

On Thursday, October 11, 2012 5:07:30 PM UTC+1, John Weston wrote:
On Thu, 11 Oct 2012 13:48:38 +0100, Phil wrote: So Norway have 400 (440?) volt mains? No, their three phase is Delta rather than Star connected, hence the lack of a Neutral connection. I found that out when fixing a problem with a three phase powered disk motor... (the disk was the size of a large washing machine) -- John W

You get most pecuilar effects if one of the three main fuses blew, disconnecting one phase and so leaving the affected rooms connecetd in series with each other.

Robert

On Thu, 11 Oct 2012 09:27:43 +0000 (UTC), Gordon Henderson
wrote:

Anyone know how they run the mains in Tenerife?

Apart from the obvious answer - "without much care" that is...

Seems there is no earth and my laptop is giving me regular shocks when
I touch some of the metal connectors - e.g. the extrnal VGA socket and
the audio sockets. Not big shocks, but enough to irritate.

My laptop's power supply is the usual little "brick" device - 3-pin
cloverleaf input, 19v output...

I'm told (by some of my family who live here) that "that's the way it is",
but I can't help thinking that maybe it could be better!

What laptop?

I can't remember if the discussion was in here or another group but it
turns out that the Apple Mac Powerbook brick is not double insulated
but has an earth continuity from a pin on the magnetic connector to
the computer through to the earth pin on the mains socket. Not
believing this, I ran a test meter over my son's Powerbook power unit
and found it was exactly like that. I can easily imagine situations
where dodgy wiring could lead to the symptoms you describe.

Nick

On 12/10/2012 09:03, Martin Brown wrote:
On 11/10/2012 23:28, John Rumm wrote:
On 11/10/2012 22:45, The Other Mike wrote:
On Thu, 11 Oct 2012 20:26:34 +0100, John Rumm

wrote:

On 11/10/2012 19:17, Brian Gaff wrote:

Which is why I'm surprised it makes any difference which way around
the
mains is connected unless the brick is faulty, which is where we
came in.

I thought this one had been done a few weeks back...

The usual setup seems to be that the neutral

ITYM chassis

Indirectly yes - but if there are only two wires to the laptop, and one
is the neutral, then that is also what gets connected to chassis.

Only if you want to die. Figure of 8 two pin cables are non polarised.
If the laptop is on a two wire connector then the PSU must be double
isolated or you have a 50:50 chance of having a live chassis.

Not sure I follow... the two wire connection from the PSU to the laptop
will have the correct polarity regardless of the polarisation of the
mains input.




--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On 12/10/2012 22:22, John Rumm wrote:
On 12/10/2012 09:03, Martin Brown wrote:
On 11/10/2012 23:28, John Rumm wrote:
On 11/10/2012 22:45, The Other Mike wrote:
On Thu, 11 Oct 2012 20:26:34 +0100, John Rumm

wrote:

On 11/10/2012 19:17, Brian Gaff wrote:

Which is why I'm surprised it makes any difference which way around
the
mains is connected unless the brick is faulty, which is where we
came in.

I thought this one had been done a few weeks back...

The usual setup seems to be that the neutral

ITYM chassis

Indirectly yes - but if there are only two wires to the laptop, and one
is the neutral, then that is also what gets connected to chassis.

Only if you want to die. Figure of 8 two pin cables are non polarised.
If the laptop is on a two wire connector then the PSU must be double
isolated or you have a 50:50 chance of having a live chassis.

Not sure I follow... the two wire connection from the PSU to the laptop
will have the correct polarity regardless of the polarisation of the
mains input.

Many laptop PSU bricks are on a two pin figure of eight non-polarised AC
mains connection with no earth. On a UK 3 pin mains plug cable the
handedness is well defined but on a continental two pin plug it is not.

To be safe a two pin unearthed PSU must be double isolated since you
cannot be sure which of the mains input lines is neutral.

It is not completely unknown to find some wiring monkey or DIYer has
swapped L & N on a UK wall socket either. In foreign parts it is as well
to assume that the electricity supply is unsafe until proved otherwise.
Ditto for the gas central heating and hot water boiler. A neon
screwdriver is a handy thing to have with you at all times...

You don't have to go far afield to find deadly gas water heaters -
Belgium has a very bad record in that regard or did when I lived there.

--
Regards,
Martin Brown

On Fri, 12 Oct 2012 09:48:40 +0100
Mike Tomlinson wrote:

In article , Jules Richardson
jules.richard writes

Electrics here in the US are seriously dodgy!

Especially if it's knob-and-tube (still in widespread use) or
aluminium* wiring.

* this is a UK group with UK English spelling, dammit.


Ah, 'aluminium' with a 'u' in it! g

Funny, I haven't seen that Enterprise ad. for a while now. I wonder if
somebody finally realised?
--
Davey.

In article ,
Martin Brown wrote:
Many laptop PSU bricks are on a two pin figure of eight non-polarised AC
mains connection with no earth. On a UK 3 pin mains plug cable the
handedness is well defined but on a continental two pin plug it is not.

To be safe a two pin unearthed PSU must be double isolated since you
cannot be sure which of the mains input lines is neutral.

That's not what double insulation means or does. You could have a
perfectly normal isolating mains transformer to provide the low volts (as
of old) which doesn't comply to the double insulation standard. I think
you're confusing things with having a live chassis as was common with old
valve TVs. In the UK, if the plug was wired correctly, the chassis would
be to neutral therefore 'safe', reverse the connections and it was at
240v. But nothing uses that these days.

--
*Nothing is foolproof to a sufficiently talented fool*

Dave Plowman London SW
To e-mail, change noise into sound.

On 12/10/2012 22:35, Martin Brown wrote:
On 12/10/2012 22:22, John Rumm wrote:
On 12/10/2012 09:03, Martin Brown wrote:
On 11/10/2012 23:28, John Rumm wrote:
On 11/10/2012 22:45, The Other Mike wrote:
On Thu, 11 Oct 2012 20:26:34 +0100, John Rumm

wrote:

On 11/10/2012 19:17, Brian Gaff wrote:

Which is why I'm surprised it makes any difference which way around
the
mains is connected unless the brick is faulty, which is where we
came in.

I thought this one had been done a few weeks back...

The usual setup seems to be that the neutral

ITYM chassis

Indirectly yes - but if there are only two wires to the laptop, and one
is the neutral, then that is also what gets connected to chassis.

Only if you want to die. Figure of 8 two pin cables are non polarised.
If the laptop is on a two wire connector then the PSU must be double
isolated or you have a 50:50 chance of having a live chassis.

Not sure I follow... the two wire connection from the PSU to the laptop
will have the correct polarity regardless of the polarisation of the
mains input.

Many laptop PSU bricks are on a two pin figure of eight non-polarised AC
mains connection with no earth. On a UK 3 pin mains plug cable the
handedness is well defined but on a continental two pin plug it is not.

Indeed.

To be safe a two pin unearthed PSU must be double isolated since you
cannot be sure which of the mains input lines is neutral.

Yes, but not for that reason. (ITYM double insulated rather than isolated).

The uncertainty of input polarity is not the factor that requires it to
be double insulated, its the lack of earth provision on the supply - or
to reverse it, it the fact that its double insulated that permits it to
be supplied with a two wire non earthed lead.

It is not completely unknown to find some wiring monkey or DIYer has
swapped L & N on a UK wall socket either. In foreign parts it is as well
to assume that the electricity supply is unsafe until proved otherwise.
Ditto for the gas central heating and hot water boiler. A neon
screwdriver is a handy thing to have with you at all times...

A non contact volt detector would be a better bet.

You don't have to go far afield to find deadly gas water heaters -
Belgium has a very bad record in that regard or did when I lived there.

All agreed.... still not sure what that has to do with the DC supply to
the laptop though (where the neutral may actually be "riding" half mains
at a high impedance).


--
Cheers,

John.

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