On Wednesday, 13 March 2019 17:38:11 UTC, John Rumm wrote:
On 13/03/2019 13:52, tabbypurr wrote:
On Wednesday, 13 March 2019 13:17:41 UTC, John Rumm wrote:
On 12/03/2019 18:21, tabbypurr wrote:

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

There are many testers that pass unsafe leads at times due to an overly simplistic view of the subject.

he does not explain the procedure he would use, so again its not
possible to decide if it would be an over simplification.

It is, reread what he wrote.

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.

really? that sounds like bad pratice


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,

It is PAT testable. A lot of testers don't understand the issues though.

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.

of course

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.

Insulation PAT testing is done at above mains voltage

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,

How many PAT passed wallwarts kill people?

or for that matter if it even has a thermal fuse.

no, PAT testing does not test BS compliance


NT