On Tue, 03 Jul 2018 04:39:13 +0100, Bob F wrote:

On 7/2/2018 1:37 PM, Jimmy Wilkinson Knife wrote:
On Mon, 02 Jul 2018 05:41:08 +0100, Bob F wrote:

On 7/1/2018 11:16 AM, Jimmy Wilkinson Knife wrote:
On Sun, 01 Jul 2018 16:16:32 +0100, trader_4
wrote:

On Sunday, July 1, 2018 at 11:00:43 AM UTC-4, Bob F wrote:
On 6/29/2018 7:58 PM, Rod Speed wrote:


"Jimmy Wilkinson Knife" wrote in message
news On Sun, 24 Jun 2018 22:11:44 +0100, Rod Speed
wrote:

Cursitor Doom wrote
ARW wrote

I wish he would try it.

I'm not wasting more time on that oaf, but just wondering
whether
we should be moving on to a 'post-earth world' for other
reasons.

To some extent we have with double insulated appliances most
obviously.

But there is still a problem with washing machines, dishwashers,
electrical water heaters and ovens and stoves etc which arent
really practical to do double insulated.

How is that a problem?

Because when a fault shows up in one of those, there
will be no indication of a fault at all and the protection
that nothing earthed used to provide is now gone.
So you no longer have any protection, and that is
over the entire collection of houses etc that are
powered from that transformer in the substation if you
dont have individual transformers for each house.

The case could be not connected to anything, and the power
could be
isolated from ground. If one side of the power touched the
casing,
nothing would happen, as it would have no desire to go to ground.

Yes, but with those devices that have other grounds
likely present via the water pipes etc, you now have
a problem that the case is at mains voltage and
touching that and the ground simultaneously and
that can certain kill you with that in separate hands
as is most likely in that situation.

What causes the danger is because live wants to go to ground,
through
you.

And that can happen post fault when the fault
produces no visible effects and the device keeps
working and there are other grounds available.

A big problem of having no ground reference in the power lines is
that
any leak to ground in any device in any house sharing the
transformer
with you can float the entire power supply to any level. If some
device
like a high voltage low current power supply made contact to either
of
the power phases, there would be nothing to stop all the power
lines in
those houses from floating up to whatever voltage it drives. Then
that
power could arc from the power connectors anywhere to any nearby
ground
or even a person standing on a concrete floor.

With devices using power referenced to ground, every device would be
sinking that low current device to ground.

I've made several posts during this long thread where I pointed that
out,
that one big reason for an earth ground system is that it provides a
safe path for dangerous surges, high voltage lines coming in contact
with lower voltage ones, etc. Lightning striking a pole or overhead
service conductors is a prime example. With one conductor tied to
ground,
it provides and easy, safe path for most of the energy. But only one
player even acknowledged the point, and he's a troll who dismissed it
and went about his usual nonsense.
Except I'm talking about the final 240V stage to the houses, which
is not usually above ground to take lightning strikes.

Which still leaves any other house on your transformer free to charge
your entire house wiring to any possible voltage with a fault as I
described above.
So I have 240V between a pair of wires, fed from a transformer. My
neighbour shares this transformer and does what? Raises one of those
to lines to 1000V above ground? How would he manage that by mistake?
Even if he did, it's not going to affect me unless I also have a fault
(eg an appliance with a short to its chassis).

Equipment failures would do it. A wire touches another wire it should
not touch. A high voltage wire on the pole dropping onto a transformer
output lead could do it. A failing CRT TV could do it. A broken
electrostatic air cleaner could do it. Any device that uses high
voltages is a potential problem.

But the whole point of floating voltages is you need TWO faults to cause a
problem. ****ing unlikely.