morning Marcus what are you up to so now we've completed all of our dead tests Gaz we're actually
going to start looking at live testing we're going to look at the importance of the first live test
which is often overlooked which is obviously rechecked polarity of supply okay so the example
being so i've done all my dead tests yeah this is not doing a live test i'm plugging something in it
works we're out of here so that's not acceptable no this is for the video purpose okay yeah we like
that so if i turn my one back off and your plug-in voltage indicator which wouldn't be the test we're
carrying out we're going to look at that in a minute what is that telling me at this stage
anyhow so from the indicating lamps on the tester it's actually showing us that we have a line
neutral reverse so incorrect polarity between line and neutral and that can't be the case if we've
done and we have all our dead tests correctly and we've confirmed the dead test polarity and we have
so we've done our bit correctly yeah so of course it must be further back in the system where we've
got an issue not necessarily at this socket so we won't be taking this socket off and confirming the
connections in the back of it which we might do an electrical installation condition report
we're actually going to go into the consumer unit and do what test again so we're going to
recheck polarity of supply of our approved voltage indicator okay let's do that next
so Marcus we're performing the tests in the correct sequence this isn't quite what we would
be doing obviously on an initial verification this might be more of a periodic thing you've
locked off the main switch yeah what's your thinking behind that for this one so the reason
i've locked off the main switch Gaz is because obviously we've got now got concerns of our
income in supply polarity so it might be an issue with the dno side yeah so if i was to accidentally
energize this main switch here then the neutral bars would actually be the line conductor
so there's a much greater risk of electric shock okay i like your thinking behind that
and if this was part of a periodic inspection where the installation condition report was being
installed i'd be looking now at the colours of conductors and colours yeah of course
so yeah as we look here are we happy that all the brown conductors are out going on the lines yeah
through the breakers cpc's and neutrals are in the appropriate places so we're not thinking it's an
incorrectly wired circuit no and we're looking at this from a point of view that our learners have
carried out all their dead tests correctly before moving on to a live test test remind me of that
first live test again recheck polarity of supply right so we're concerned about the incoming supply
which could be reversed where could it be reversed so it could be reversed at the meter so if you've
maybe had a new smart meter installed okay but we have actually checked that and it isn't the case
so now we're looking further down the line which is the dno side okay we're concerned about it
again we've got a links main or double pole switch here again we've confirmed that the connections in
there are correct we leave the connections here correct through tracing them through
so we're actually thinking it could be possibly in the road yeah maybe they've done a joint and
done an incorrect join somewhere however if it is
a reverse polarity and it was at the meter is that something we could change ourselves
no so we would still need to ring the energy supplier or the owner of the meter itself maybe
British gas something like that okay so let's get prepared for the next test which is just to remind
me again rechecking polarity of supply which is really important so all the awarding bodies
and endpoint assessments require us to check our voltage indicator for using it is that the case
even though we're doing this supply polarity check yeah so just like the safe isolation steps
Gaz we're going to have to prove our approved voltage indicator first now we could do this
on a known source or reproving unit however i'm going to do this on a proven unit today
okay so yeah so good yeah so on to the test itself now yeah okay we've jiggled the camera around
we're going to try and keep our view and i've got one end of the voltage indicator and i have the
other one okay so you tell me what we want to do Marcus first so the first step we're going
to do we're going to go between line and earth so i want you to probe on to the least dangerous
conductor first being the earthing conductor so the earth bar here yeah i'm on to that and then
i'm going to probe onto the line now this is where we should expect to see voltage however
where our concerns were earlier we're not seeing voltages so my concern is line and neutral reverse
okay and that was what we were indicated on the plug-in voltage indicator as well when so
i'll take off mine now so some precautions now moving forward because we'd expect now
possibly it to be live this time so if we go back onto the earth bar where the cpc's are connected
so leave first then the most dangerous voltages appeared okay so you'll need to come off yours
first and then mine so we'll still prove the third one we will go in here but we're going to be some
cautions now yeah because normally we've gone the least dangerous being the neutral however now
we've got suspicions the neutral is actually the line conductor we're going to have to program to
the line conductor first and then the neutral do you want to do that for me so you're going to go
on the line conductor first this is odd and then on to the neutral and hopefully yeah we can see
that yeah that's illuminated so you're going to come off the the neutral being the most dangerous
it's a bit of an awkward one when you're not used to it so we've got a reverse polarity so we've got
the line and neutral that are correctly colour coded here yeah they're actually physically the
wrong way around it's back here so we understand by looking that the connections are correct here
and correcting the meter inside so we believe the issue is down here actually in the road maybe
like essentially yes so all it leaves us now to do Marcus is pull the camera back recheck our voltage
indicator on a known source or a proven unit in our case and then just summarize where we got to
so now that i've gone through them stages all that's left me to do is now re-prove my voltage
indicator i'm going to do that back on my proving unit and as you can see everything is still fine
so think of this as the scenario you've done all your dead tests they're all correct yeah you've
done continuity cpc's and your polarities you've energized your installation first test being the
re-check and supply polarity okay good and we've got to now check that and actually we've got a
reverse polarity of line and neutral in this installation right okay if we hadn't done that
we'd livened up all the circuits markets nothing would work would it yeah everything would work as
normal no so what would be now a risk so we've got certain risks such as Edison screw lamp holders
the outer contact instead of being connected to the neutral now will be connected to the line
conductor um our polarity of our socket outlets they will also be incorrect yes and also a big
one for me guys is all single pole devices will not no longer be switching the line conductor
however they'll be switching the neutral so in the event of let's say an exposed conductive part
becoming live ADS will not disconnect the circuit breaker in the correct time so what we're saying
there is that with the reverse supply polarity the fuse is in effectively now the neutral
conductor yeah and not in the line conductor right the outer metal work becomes live yeah
we're expected to disconnect under ADS but we've actually got the fuse no fuse in the neutral no
so we've got a chance that the circuit isn't going to disconnect no leading to a risk of three things
those three things are shock fire and explosion that's one for our learners okay so obviously
yeah we can see how crucial it is then that the first test is put in place correctly yeah because
obviously when we start doing earth fault loop impedance tests having not done supply polarity
we'd be probing and thinking oh this doesn't work it doesn't work what's going on and you
start unpicking circuits yeah when actually it's the supplied polarity and just the simpleness
of that first live test yeah ensures you that you have the correct supply plan and you'll be
expected to do that and you're sitting guilt and EAL internal assessments as well as your external
AM2 or AM2S as well so me and Marcus hope this has helped you both in testing and fault finding
and we'll follow it up with we hope this video has been some help