On Mon, 28 Jan 2019 07:42:45 +1100, "Steven" wrote:



"Archibald Tarquin Blenkinsopp" wrote in
message ...
On Mon, 28 Jan 2019 07:14:47 +1100, "Steven" wrote:



"Archibald Tarquin Blenkinsopp" wrote in
message ...
On Mon, 28 Jan 2019 06:43:14 +1100, "Steven" wrote:



"Archibald Tarquin Blenkinsopp" wrote in
message ...
On Sun, 27 Jan 2019 17:35:06 GMT, Harry Bloomfield
wrote:

It happens that Roger Hayter formulated :
The contact failed because either;

- it was never screwed up properly (and this would not stop it
working
for an uncertain period);

- vibration from switching caused the screw to unscrew;

- or the copper gradually deformed under pressure;

It looks to me as if the copper core failed and snapped, leaving the
copper part still in the terminal. Possibly the installer nicked the
copper as he stripped the insulation and it subsequently snapped. Poor
or careless technique.

Probably repeated in other parts of the installation.

But it isn't actually viable to completely redo all the terminals in the
entire house now. Given that the wiring standards are fail safe by
design, it make more sense to fix any others that do fail when they do.

You steamin' great pillock! Fail safe by design?? No such bloody
thing unless you are working to ATEX standards.

Have you seen a glass rod conduct electricity to the point where it
melts and arcs.

Doesn't happen in the sort of house the fault was in.

The laws of physics are universal, they apply in everyones house.

There isnt a high enough voltage in that house to melt any glass rod.

There is, I have seen it, and repeated the event under "controlled "
conditions.

I have also measured the Voltage on the old RS build your own dropper
elements. Start to take a few hundre mA and you could measre the
Voltage on the Ceramic insulator.

Have you examined insulation that has been drenched and suddenly
become conductive.

The RCBO system fails safe in that situation.

No it does not.

Wothout an earth path the MCB has no clue whether the couple of kW is
a genuine heating element or a L-N leakage path.

Isnt going to happen with that 2 way light switch circuit.

Likewise although a switch alone is perfectly capable of providing an
audio visual indication of a gas build up, a loose connection will
give the indication a lot earlier and with a higher level of success.

Yeah, yeah, the entire house should be completely rewired now that that
one wire was clearly not as competently done as it should have been.

Only the circuit that was done when that switch was installed.

Which was almost certainly done when the whole
house was wired when it was built in the 1980s.

I would
hope that it was an "add on".

It wasn't.

Choose your insurance carefully!



Easy to see why no one would employ you in britain and you had to
move to ireland and then even they noticed how unemployable you are.

I am actually employed in Britain, on a much higher salary than I was
with my previous British company.

Only until they too notice how completely unemployable you are,
just like the Irish did so quickly.

On my next foray to Ireland I most certainly will not be looking to
start work!

Britain might not see too much of me either you will no doubt be glad
to hear, but if I need to depart fairly soon, I would have every
confidence that light switches will be the least of your worries.

AB