Archibald Tarquin Blenkinsopp wrote:

On Sun, 22 Apr 2018 12:36:29 +0100, (Roger Hayter)
wrote:

Archibald Tarquin Blenkinsopp wrote:

On Thu, 19 Apr 2018 08:51:31 +0100, (Roger Hayter)
wrote:

Archibald Tarquin Blenkinsopp wrote:

On Wed, 18 Apr 2018 17:46:17 +0100, Rob Morley
wrote:

On Tue, 17 Apr 2018 20:27:55 +0100
Archibald Tarquin Blenkinsopp wrote:

No,
With no load it is neither alive nor dead.

If there's potential difference WRT ground it's live even if there's no
current. Neutral can also be slightly live. ;-)

To measure the potential difference you have to apply a load.

When you apply a load, the line becomes live or dead.

Now my mate Erwin has an iffy pussycat,
................................

AB
In principle you do not have to apply a load, for instance a bridge
method can be used which while it may apply a minimal load, or a minimal
generator during adjustment has neither at balance.

Only at the measuring device itself, the bridge must sink current.

The bridge at one side of balance supplies current to the DUT and at the
other side of balance sinks it. It therefore passes through a point of
zero current at balance.


Correct, it depends how the bridge is configured of course.

As the observation has been made, it has affected the measured circuit
thus the the cable has become live, or not.

A bit like sticking a bowl of milk into tiddles safe, it may not be
touched, but the interaction means that Tiddles is alive, or dead
maybe.

AB

No, you are simply wrong. The potential (emf) on wire is there totally
irrespective of current flow into a measuring instrument or anywhere
else. There are no quantum effects on the scale involved. For
instance, if the voltage is high enough you will get corona effects
regardless of current flow.

--

Roger Hayter