[quote author=L.Spark  link=1108845227/45#50 date=1112024892]
in answer to you're question, we use a shorting lead to make a loop, a loop that consists of r1 and r2, where
r1 is you're phase conductor and
r2 is you're circuit protective conductor (CPC)

so in essence we short phase to earth so we include both phase and earth when testing, we are then including both cable's or paths in our test..

this does however have nothing to do with insulation tests, you would not create any shorts normaly whilst undertaking insulation tests, only in certain circumstances where equipment is liable to be damaged by test voltages
[/quote]

Thank you for your reply  L.Spark

I am  going  nuts   because when i was on a 2391 course , for some reason, we used a shorting lead on a 3 PHASE system when doing insulation + polarity ,which dare I say/in my opinion     is not right, is it?

Cheers

[quote author=Lectrician  link=1108845227/45#52 date=1112029019]I suspect on 3 phase, you shorted the 3 phases together with a link and measured from this link to N and E.  You then removed the link to measure between the phases. [/quote]

Many thanks  Lectrician !

On the course , we shorted between phase and earth on the 3  phase board.

When  I asked why we did this on an insulation test  , I was told it was due to taking the neutral link out


I don't know ....

[quote author=L.Spark  link=1108845227/45#54 date=1112034480]  these sort's of questions are a bit strange for one whos undertaking diy work, [/quote]

Thank you L.Spark  .
Any opinions   ???  on this  last one, please ? -How do you check CPC continuity which is incorporated inside steel trunking and conduit , since this will create a PARALLEL path ? - RE: three phase installation which also has SWA and MICC cables

Many thanks.
I am NOT  doing any work not even domestic nevermind  commercial or industrial .   I am just  (curiously)  looking at exam and practical issues in order to decide if I should go for an exam in 12 months' time after I go to college, acquire some (more   ) knowledge

If your not at college or working, can I ask where your getting these questions from then. When we take exams we are not allowed to take papers home, so where did you get yours friend.

Regards T