On 13/03/2019 13:52, wrote:
On Wednesday, 13 March 2019 13:17:41 UTC, John Rumm wrote:
On 12/03/2019 18:21, tabbypurr wrote:
On Tuesday, 12 March 2019 13:15:08 UTC, Bill Wright wrote:
On 12/03/2019 03:57, Archibald Tarquin Blenkinsopp Esq wrote:

Like yourself though, they all knew everything there was to
know about the subject even before they did the course.

Your sarcasm fails because actually I do know everything
necessary to check the safety of a mains extension lead. As do
many people.

Unfortunately for technical pseudo-elitists it really isn't
rocket science.

Bill

You're welcome to your opinion, but this time it's just wrong.

Its likely that its not wrong, however since you don't have
adequate information to assess Bill's competence to verify if an
extension lead is safe, the statement is pointless.

he is oversimplifying the requirements of PAT testing.

Firstly, he was not talking about PAT testing in the broad sense, just
that "necessary to check the safety of a mains extension lead". Secondly
he does not explain the procedure he would use, so again its not
possible to decide if it would be an over simplification.

Testers that
do so make bad choices here & there, exposing others to risk &
themselves to the courtroom.

Of course they do - in fact we all do.



Under different circumstances I'd test you by showing you a bunch
of difficult appliances to test. Let's get some examples I've
encountered that would catch many pat testers out:

You seem to be discussing more than just extension leads here...

1952 Hoover floor polisher 1937 McMichael radio 1951 Hoover
junior vacuum cleaner 1934 2 valve reaction set, home made Fan
heater, 1960s or 70s

as I said he can confine himself to extension leads if he wishes. I'm
curious to see if he picks up on all the real world gotchas.

Can't see those being common in the average office, and your
average PAT testing course is unlikely to dwell on specific
instructions for vintage kit.

and there lies a problem. I do test vintage kit. There are all sorts
of gotchas one does not see in modern kit. And yes, some of it does
pass.

Testing vintage kit is well beyond the scope of PAT testing, and there
is a moderate amount of kit out there that would never have been be able
to pass a PAT test - even when new.

Modern 6 way extension lead Modern LED lights Assorted wallwarts
Fan heater, 2017

Wall warts in particular show one of the weaknesses of PAT tests -
many are fundamentally compromised by poor design and yet you can't
see that from outside of the box, and testing to prove the point
would be destructive so unlikely to be popular with clients.

OTOH the test voltage used should suffice to demonstrate them
adequate (or not), even if not BS compliant. A PAT pass does not
require BS compliance.

While a PAT will include an IR test, it won't do a test with transients
on the mains supply. Hence no way to verify if the internal separation
between mains and ELV is adequate, or if the internal insulation of the
transformer is up to it, or for that matter if it even has a thermal fuse.

99%+ of what you will meet PAT testing for businesses requires
some experience, a small amount of test gear, and a basic level of
understanding of electrical principles. Its a skilled endeavour,
but trainable. It does not require a graduate level engineer.

But the other 1% is less simple. I've seen so many PAT test
screwups.


NT

Rocket science on the other hand is difficult - not least because
it involves a vastly wider range of disciplines and far more
difficult sums!


--
Cheers,

John.

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