in a previous video designed to help you with AM2 AM2S and AM2E your end point assessment
for apprentice electricians i suggested that you are required to disconnect the protective
bonding conductor at both ends the MET and where it's connected say to the gas and water pipes in
order to prove its continuity and remove parallel earth paths and i produced this video just here
however it's come to my attention that you don't the first part of the assessment which is your
install you can just test it as i've shown previously on the channel and i'll leave a
link for that in the eye above my head and in the description below so you can check out that video
we disconnect it from the met use our long wandering lead and check it against the
actual connection and the pipe in order to prove continuity however it would be advantageous to
disconnect it at both ends from the MET and from the pipe work so you're testing just the cable
when you do the fault finding element of AM2 AM2S and AM2E in order to find that fault so in this
video i'm going to go through pictorially how to carry out the protective bonding conductor test as
well as how to do it when you're looking for the fault finding element and prove to you how we can
find that broken conductor by disconnecting both ends if you want to skip to any part of the video
please check out the time stamps they're in the description below or you can click on the screen
so you can jump forward if you're just interested in that element which is the fault finding let's
go to the desk and have a look at what we've got set up i'm going to show pictorially what you've
got your end point assessment i've drawn here the three phase distribution board i've got a separate
MET main earthing terminal as you will have on your rig and you will install a new circuit for
the protective bonding to the water and to the gas and i've simulated them coming in in metal
so this makes these extraneous conductive parts we need to test this protective bonding conductor and
i've done that many times on the channel before and i said i'll leave that in the description
the eye above my head but you've also got to remember that you must isolate and lock off
the distribution board and again i've shown that i'll leave it above my head and in the description
how to carry out the safe isolation when you've got a three-phase distribution board so once
we're safely isolated we can start thinking about disconnecting our protective bonding conductors
and carrying out the tests having set up my multi-functional tester to ohms remove the
resistance of the lead we're ready to carry out the test so i've simulated here obviously
a disconnected from the MET i've disconnected my water protective bonding conductor and i'm going
to test from the disconnected end to the actual connection on the bonding clamp and then to the
water pipe and i'm going to record the highest of those two readings so if i take my leads i'm going
to bring my lead out to my disconnected protective bonding conductor i've got it here slightly larger
you can see i've removed it from the MET in order to make an electrical connection and then my
second lead goes on to the connection on the clamp so where we've made the connection onto the clamp
and we measure that resistance so we're measuring the resistance of the protective bonding conductor
however i like us to measure not just to the clamp but also to the pipe this pipe needs to prove that
it's got an electrical connection imagine if the clamp went around paint or comb say tarnished or
corroded elements of the pipe work you might not have a very good electrical connection onto the
copper pipe itself so i need to prove it onto the pipe so what i'd end up doing is leaving my lead
connected to my disconnected protective bonding conductor and move my lead off the actual clamp
and onto the pipe in order to make that test record that reading so that would prove that the
protective bonding conductor newly installed is continuous in other words we measure its
resistance in ohms and i measure it to both the actual clamp and pipe work in order to prove it's
electrically connected and then i can reconnect it into the MET and work with the gas one next
so i've now disconnected the protective bonding conductor that i know goes to my
gas remember i've installed these myself and you can see here clearly it's disconnected from the
MET you could leave them both out at this stage i've put one back you don't have to
put it back but they will need to go back in at some point exactly the same process
one of my leads comes onto the disconnected protective bonding conductor for the gas
and then the other one goes on to the clamp there for the gas so we can prove that that conductor is
continuous we measure its resistance and likewise we do exactly the same as we did before we leave
our test lead on the disconnected one for the gas and then we make a connection onto the gas pipe
to prove that the clamp makes a good electrical connection to the metal work of that pipe so that
would be that one the next one's interesting because this is now where we're thinking about
the fault finding in the next part of the video let's think about the fault finding element of
your endpoint assessment and think about maybe if there was a broken protective bonding conductor
so what i've got here is i've got my protective bonding conductor to one pipe don't know what pipe
it is i've got my protective bonding conductor to another pipe now the likelihood is you'll
only see this element here at one end so you'll see where they're connected to the pipe work
and you'll have access to the MET in order to disconnect the protective bonding conductor under
test you'll be set a scenario but let's think about what could happen when you do this test
if you do disconnect them one at a time from the MET okay and don't disconnect them from both ends
so in the first case i've disconnected one of the protective bonding conductors
from the MET i don't know which one it is because obviously i've not installed these
and i don't know where they're going i can't see the run so i've disconnected one of them
so we'll put one of our leads onto that onto the protective bonding conductor disconnected
and then i'm going to put my other lead not knowing which end it is onto this clamp here
okay and then we'll see if we think we'll get a read in so we come on to here onto the clamp so
now i measure the resistance that goes down this conductor here and disappears it goes into this
pipe work and let's say that this is i don't know the water pipe and the water and gas are
connected together we know at boilers and places like that so the pipe work is a connected together
would i get a reading so let's let's work that out so i measure the resistance down this conductor
down here okay to here okay i get a i get my circuit so i get a path through there
yet the protective bonding conductors are actually feeding this pipe work is broken
and i've picked up the parallel earth path here now it could have been you could have been lucky
couldn't you you could have tested to that one first and then test disconnected and we'll look
at that in a second and you may have i've stumbled across it but look at that how unlucky have you
been disconnected one of the protected bonding conductors got onto one of the pipes and got a
reading then you reconnect it okay and then you go again so let's look at what could happen then
let's imagine second scenario we've got disconnect our protective bonding conductor
to here okay i've disconnected that protective bonding conductor and then i'm going to test to
the other clamp okay so i'm going to test it to the other clamp so i'll come up and i'll test it
to the other clamp just there so now have i got a circuit okay so i come down here it's broken
there and obviously we do not get a return path out so all of a sudden now you get a little bit
confused don't you because this one now hasn't got a reading you had one previously so if we go
back here we had a previous reading to here okay through here through here and through to there so
we thought that one was continuous but actually it was the gas one that we were measuring and when we
come back here and we've got the one disconnected now say to i don't know the water whatever we're
testing we've got this one disconnected and it's broken and i haven't picked up a reading
so that becomes a little bit of an issue so what you're thinking now is hang on a minute what if i
what if i go back and i test again so you you're panicking you're panicking
so we bring it back in and you're thinking right okay i'll i'll disconnect and try again so you
disconnect and try again so you put your lead onto here okay and then you put your other lead onto
you go back to this pipe right so will i get a reading now remember you can't see the cable runs
so i do like hang on i get i get a reading so that one that one's connected
and then but i've got a reading on this one so if we go back to it if we put that one back in again
the lead it's got another lead as if i've done another lead there would i get that reading so
i've tested this one i get a reading and i just move my probe across to the other one thinking
i've got a problem here i don't know what's going on would i get a reading well i come through this
pipe work through the parallel earth path and i get a reading and you can see how easy under the
pressure of an AM2 an AM2S or an AM2E under the fault finding one you might think well i'm getting
the protective bonding conductor continuous from this one and i'm getting it from this one so
what's going on how could you make that easier for yourself when you're doing that fault-finding test
well it's easier to disconnect them from both ends removing then the parallel earth path created here
so if i bring this one in what we've got now so fault finding rig i'm thinking about it
i've disconnected both i'm going to carry out my protective bonding conductor test
i'll bring my first lead in i'm going to put it on one of them disconnected
okay i'm going to disconnect it from the other end so i'm going to need to remove it
from here so we're going to need to remove that connection just here so we're going to take that
one off and we're going to take that one off by disconnecting them both from here you remove this
parallel earth path so i'm going to test it to disconnect it this end so bring my other lead in
bring it around and i just there to my disconnected point i proved that that conductor is
continuous i bring it round and that one is proved as continuous if i disconnect this one here and i
was to test here you would find that that wasn't the conductor you wouldn't have it at both ends so
if i left it on there i tested there disconnected no parallel earth path is also broken so that
would prove that one if we bring the next one in and we disconnect it once again from the clamp
we disconnect it there and we disconnected both ends here and we bring our test leads in remember
we're going to test this one now so we bring our test lead in and to a disconnected protective
bonding conductor here in the fault finding rig you would instantly find that that one is
broken you would find that straight away that it comes through there and you have no reading
again if you were the opposite way around with and disconnected you'd find you wouldn't have
a reading but that's what we've got so we've got it disconnected under the fault finding one
removes the parallel earth path created here which joined the pipe work together so as
i said previously when testing your protective bonding conductor for your newly installed cable
by all means just disconnect it from the met and test it to the clamp and the pipe
work when you're doing your fault finding testing disconnect it from the met and the bonding clamp
because if there is a parallel earth path you can start getting confused why the two
sometimes get a reading on one of them with both cables and on the other one you don't
get a reading by disconnecting it at both ends and the fault finding element you will find if say for
instance got a broken cable and an interconnection with a pipe work creating a parallel earth path in
my one of those videos this end part you need to watch a couple of times and really think about it
but i think when you're doing your endpoint assessment and the fault finding disconnect them
from both ends your protective bonding conductor and when you're testing your gas and water of
your installed installation just test it as we always have disconnected the met clip onto there
go to the clamp go to the pipe work and prove the continuity of those conductors i hope it's
cleared up the video that i previously sent out i was semi-right in it it's probably here that you
need to disconnect both ends and default find him and as always i hope this video will be some help