In a previous video i looked at this R1R2 link and suggested when carrying out the
continuity of CPC test in a college environment it will make your life easier by clipping onto
the earth bar the crocodile clip and using the magnetic end to sit on top of your circuit breaker
of the circuit under test then it rose a few questions the first one being
is it going to be able to get onto an RCBO so i tried it on the Lewden one
the Lewden have got a large connection for their RCBO and it fitted comfortably onto that
i tried it on to a Wylex AFDD which has a lot smaller terminal fits on there
and obviously we just linked to that earth bar and also tried it on an MCB from Wylex that had quite
a deep um terminal so in other words he had to go in quite a long way in order to get the magnetic
tip to touch and in all three cases it worked perfectly well the other question i got asked was
will it add a lot more to the resistance because this will only just touch onto the terminal so
as we go on like so that's just held on by the magnetic element of it so today i'm going to see
if it adds much to the resistance to answer that question i've got a bit of a rig set up here so i
like to put the line conductor under test in the earth bar with the CPC and go out into circuit to
make my circuit realistic and long i've got these two drums of cable here and we're going to measure
the resistance of them linked like so then i'll bring my RCBO in and i'll put my line connection
in there and i'll redo the test using the R1 R2 link to see if it makes a massive difference
right so setup wise first of all we need to remove the resistance of our leads so what we got there
and yep so that's sitting at zero so it's not flashing remember if it's flashing has gone
below zero i've got them linked together in the consumer unit i'll walk out into
my installation i'm going to test between my CPC and my line connection and i've got a reading of
1.75 ohms so when i now put an RCBO in place it'd be interesting to see
what that new reading would be with the link in place so i dropped my line connection out of my
earth bar and i'm going to just pop it into the top of my wireless one because it's got a lot
smaller termination in there and that was one of the concerns so if i pop it into there i'm
going to tighten that down as if it was in situ make sure it's nice and tight i've got a torque
screwdriver but i will just do it firmly up okay so it would normally be using a torque screwdriver
in order to get it back to required manufacturer's torque setting so we can just pop that onto there
we can now test between these two points here remembering we're going to need to remove the
resistance of the link so let's do that next so clip onto my link and then we see what we've got
there press my test button once press it again it's zero so it's not flashing zero so we got one
point seven five last time drop it on there with our magnetic connection onto our earth bar so our
link is in position back out into the installation onto our CPC and onto our line connection
and let's see what reading we get and we've got a reading of we've got one point 1.8 okay so a
fractionally different reading there is it enough to cause you any concerns that's a decision you're
going to have to make but in a college setting this link is absolutely brilliant from the point
of view the amount of times the terminal on top of the MCB or in this case RCBO has to be undone
taken out and putting in an earth bar and done up in order to carry out your continuity test for
me in a college setting the fractional difference there on the reading wouldn't cause me any concern
so we look back yeah it's about 0.04 0.05 of an ohm difference so that's something you're going to
have to make as your own personal decision if you end up getting these i am not being paid to make
this video there is no um benefit to me if you go out and buy one of these i will leave a link
to the gentleman's um website in the description so if you decide you want to get one it will be
personally your choice but from a college point of view i think these are fantastic these R1 R2 links
will mean that those screws do not get damaged but as always i hope this video has been some help