On Mon, 04 Aug 2014 00:15:13 +1000, Phil Allison wrote:

"mick"

Sorry Dave, but Phil is right on this one.

** And all the others for over 8 years.


The fact that it's an isolating transformer doesn't matter, it's the
fact that it's in an "earthed" metal enclosure (or it should be) and
both plug and socket are wired incorrectly.

** Only the plug needs to be wrong ( N-E reverse) for the LETHAL
scenario to arise.



No. In the UK Neutral is virtually (if not identically) at Earth
potential. If you reverse N-E in the plug and the socket is wired
correctly then all that happens (unless an RCD is in circuit, in which
case it will trip) is that the equipment works. True, the metal housing
is connected to Neutral but that isn't a dangerous condition in this
case. (Yes, I did draw it out. )

The Live conductor is connected to one side of the primary of the
isolating transformer, both sides of the secondary are floating so there
is zero voltage between either of them and the live mains connection.



Phil: In the UK it isn't all that easy to reverse Earth and Neutral
connections in either the plugs or sockets now.

** Yes it is and "now" was not the issue in question.


Oh? When did you last look at UK electrics? Why did you omit my reasons
for writing that? In the past the use of green for the earth conductor
did cause problems for people with red/green colour blindness (who also
used to mix it up with the black neutral conductor), which was one of the
reasons for adopting the european green/yellow stripes. Anyone with
eyesight good enough to see inside a plug can now pick out the colour
difference. Also, the Earth pin of the plug is clearly offset away from
Live and Neutral (just in case you've forgotten).

Dickhead.

"mick"
Phil Allison wrote:
"mick"

Sorry Dave, but Phil is right on this one.

** And all the others for over 8 years.


The fact that it's an isolating transformer doesn't matter, it's the
fact that it's in an "earthed" metal enclosure (or it should be) and
both plug and socket are wired incorrectly.

** Only the plug needs to be wrong ( N-E reverse) for the LETHAL
scenario to arise.


No.

** FFS wake up dickwad - the topic is the use of an ISO tranny !!!

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

Bet the Beeb et alia stopped doing that when they nearly electrocuted the
first guitarist.

1. The most common error in AC plug wiring is Neutral-Earth reverse - the
item works and there is no big problem until you find an AC outlet that has
Active and Neutral reversed.

2. Add a 240:240V iso-transformer that carries the supply ground through to
the outlet and it becomes instantly lethal. Draw it out on paper if you
doubt me.

FYI:

Supply earth goes direct to one side of the amp's AC tranny, then comes the
iso-tranny's 240V winding and back to the amp's chassis. The amp will not
run - but the chassis is 240AC live relative to earth.

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

Draw it out *carefully* or try it !!!

****head idiot.



..... Phil

On Mon, 04 Aug 2014 00:56:30 +1000, Phil Allison wrote:


FYI:

Supply earth goes direct to one side of the amp's AC tranny, then comes
the iso-tranny's 240V winding and back to the amp's chassis. The amp
will not run - but the chassis is 240AC live relative to earth.



You're looking at an equipment plug being plugged into a fixed ISO tranny
that's plugged into a correctly wired mains socket? Ah... I was looking
at the tranny primary-side plug being wrongly connected, sorry. Yep,
the chassis is connected to mains earth via the isolated supply and the
amp's supply tranny in series.

"mick"
Phil Allison wrote:

FYI:

Supply earth goes direct to one side of the amp's AC tranny, then comes
the iso-tranny's 240V winding and back to the amp's chassis. The amp
will not run - but the chassis is 240AC live relative to earth.

You're looking at an equipment plug being plugged into a fixed ISO tranny
that's plugged into a correctly wired mains socket? Ah... I was looking
at the tranny primary-side plug being wrongly connected, sorry. Yep,
the chassis is connected to mains earth via the isolated supply and the
amp's supply tranny in series.

** Correct - the result is 100% lethal.

Yet *another* good reason NOT to use an iso tranny on a repair work bench
as the regular AC supply.



..... Phil

In article , Phil Allison
scribeth thus

"mick"
Phil Allison wrote:

FYI:

Supply earth goes direct to one side of the amp's AC tranny, then comes
the iso-tranny's 240V winding and back to the amp's chassis. The amp
will not run - but the chassis is 240AC live relative to earth.

You're looking at an equipment plug being plugged into a fixed ISO tranny
that's plugged into a correctly wired mains socket? Ah... I was looking
at the tranny primary-side plug being wrongly connected, sorry. Yep,
the chassis is connected to mains earth via the isolated supply and the
amp's supply tranny in series.

** Correct - the result is 100% lethal.

Yet *another* good reason NOT to use an iso tranny on a repair work bench
as the regular AC supply.



.... Phil



What do you use then Phil?..
--
Tony Sayer

In article ,
Phil Allison wrote:
Bet the Beeb et alia stopped doing that when they nearly electrocuted the
first guitarist.

You, of course, know better than the engineers at both the BBC and ITV
companies *at that time* - before RCDs etc were available.

There were many occurrences of musos getting electric shocks at gigs where
their gear was mixed with house PA systems - as was once the norm. Even
fatalities.

This never once happened in a BBC studio. QED.

--
*Bills travel through the mail at twice the speed of cheques *

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

"Dave Plowman Criminal Psychopath "

Phil Allison

Bet the Beeb et alia stopped doing that when they nearly electrocuted the
first guitarist.

1. The most common error in AC plug wiring is Neutral-Earth reverse - the
item works and there is no big problem until you find an AC outlet that has
Active and Neutral reversed.

2. Add a 240:240V iso-transformer that carries the supply ground through to
the outlet and it becomes instantly LETHAL.

Supply earth goes direct to one side of the amp's AC tranny, then the
iso-tranny's 240V winding and back to the amp's chassis. The amp will not
run - but the chassis is 240AC live.



..... Phil

In article ,
Phil Allison wrote:

"Dave Plowman Criminal Psychopath "

Phil Allison

Bet the Beeb et alia stopped doing that when they nearly electrocuted
the first guitarist.

1. The most common error in AC plug wiring is Neutral-Earth reverse -
the item works and there is no big problem until you find an AC outlet
that has Active and Neutral reversed.

2. Add a 240:240V iso-transformer that carries the supply ground through
to the outlet and it becomes instantly LETHAL.

Supply earth goes direct to one side of the amp's AC tranny, then the
iso-tranny's 240V winding and back to the amp's chassis. The amp will not
run - but the chassis is 240AC live.



You seem to have started a new thread quoting just yourself?

Must be the problem when typing with one hand.

BTW, it's very easy to invent a series of stupid reasons why tried and
tested safety measures won't work. By people who don't live in the real
world.

--
*We waste time, so you don't have to *

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

In article , Phil Allison
scribeth thus

"Dave Plowman Criminal Psychopath "

Phil Allison

Bet the Beeb et alia stopped doing that when they nearly electrocuted the
first guitarist.

1. The most common error in AC plug wiring is Neutral-Earth reverse - the
item works and there is no big problem until you find an AC outlet that has
Active and Neutral reversed.

Mind you in the UK moulded on plugs have been around years and years now
haven't got one screw-on one her anywhere and can't remember the last
time I saw one.

As to adversely wired mains sockets anyone here ever seen one connected
arse about face?. Three pin ones that is, two pin are only on the backs
of QUAD 33 pre-amps..


--
Tony Sayer

"tony sayer is a stinking pommy **** "

Phil Allison

Bet the Beeb et alia stopped doing that when they nearly electrocuted
the
first guitarist.

1. The most common error in AC plug wiring is Neutral-Earth reverse - the
item works and there is no big problem until you find an AC outlet that
has
Active and Neutral reversed.

Mind you in the UK moulded on plugs have been around years and years ...


** Shame that does to apply the matter in question.


As to adversely wired mains sockets ....


** Not the matter in question either, but the lack of such miswired outlets
backs my point up.

Now go back to your kiddie fiddling - ****head



..... Phil