I am going to be there really Gaz it's going wow you made that look easy... effortless
so then Joe early part of the academic year its September to Christmas all the Learns
at Tresham College are working with flat profile PVC twin and CPC cables lighting circuits
and socket circuits we're using grey outer mechanical protection sheath cables I see
you haven't got the same your side no over here we've got some white covered cables so
again we still looking at a similar type so we've still got twin and CPC and in this case
we've got three core and CPC but it's got this white sheath on the outside and what
does that white sheath tell us about this cable Gaz it's an absolute nightmare to put
in tells us isn't it and quite difficult to put the bends in that we actually put into
the gray version of your same cable absolutely and there's a slightly different method when
you're on site of actually making those bends something maybe I learners won't experience
until they're actually on site what's causing this to have such a different feel to it Joe
well these we've got here and this is a different kind of mechanical protection that's on the
outside and a different kind of insulation that is covering the conductor's okay the
grey cable that you've got in front of you yep is insulated and sheathed with PVC okay
which were quite familiar with happy with and the designation for that type of cable
is 6242YH for harmonized cable whereas what we've got here is 6242B cable and the last
letter indicates the material that is acting as the insulation and or the sheath so this
is sheathed with some kind of low smoke and zero halogen material okay now what that means
is if we go back to our PVC cable yep if in a property whether it be perhaps a residential
property or whether it be but perhaps a commercial property have something like that if a fire
breaks out and the PVC cables in that building start to burn okay starts to give off a lot
of black smoke which can make exiting the building very difficult and also that smoke
is not good for you it's bad for people to breathe in and it also produces a type of
halogen gas called hydrogen chloride so when chlorine is one of the halogen gases and when
it combines with the halogen in the cable it makes this gas now the gas is very dangerous
for humans to breathe in and also if it combines with moisture in the atmosphere it actually
creates hydrochloric acid oh dear and that is really dangerous for people buildings property
the electronic equipment in the building it's bad news so in order to protect all of those
things some specifiers some designers some councils will have their buildings wired up
with low smoke and zero halogen cables okay now there's a small sticking point you'll
see an awful lot of cables with slight variations on the theme so it might be LSOH it might
be LSNH which is the one that Doncaster cables uses that what's off about in a minute you
might see a few variations on that the thing you've got to be really careful about is that
there is a difference between LSF cable right which stands for low smoke and fume and low
smoke and zero halogen cable okay so low smoke and fume cable is not strictly regulated and
it can still give off dangerous gases they can wear as low smoke zero halogen cable has
to that it emits so don't be tricked into thinking that low smoke fume is the same as
or as safe as meet very strict requirements for the emission of hydrogen chloride halogen
gas and the smoke low smoke and zero halogen it's not and that's what we've got in front
of us so we know the properties are very difficult for us to install in fact is the same current
carrying capacity etc however putting bends in it is quite difficult and the key to this
video is actually removing in this case the white mechanical protection is a lot more
difficult than what our learners have been experienced in these early weeks of removing
the grey version so Doncaster cables kindly when we went up there and shot a video with
efixx and check out efixx.co.uk for that video and article allowed us to take away their
cable of low smoke and no halogen and we can see Joe that it's actually got a groove down
the centre yeah the one you've got there hasn't known is it by a different manufacturer on
a groove so what was the reason or thinking behind a Doncaster cables inserting this groove
into the cable well it's a really smart idea because that groove is designed to help you
run your knife down the cable okay in order to get the CPC out and then remove the rest
of the mechanical sheath that's on the outside of there so that's the idea behind that and
we're gonna see if it makes installing stripping this cable a little bit easier okay I can
engage so we've got the cable on the bench in front of us I can see you've got your stripping
knife there ready to go and we're gonna try and strip this cable using the knife using
that groove that's been put into the cable there to make it easier to strip just a point
on safety obviously we don't like moving enough towards your body in case it slips off the
cable and cuts into yourself but Gary is standing with his body to the side of the knife as
he draws it back and so he's very very safe while he's doing this so do you want to demonstrate
that for us Gaz yeah so gonna run the bring the blade down the groove and then we're gonna
see if it is easier to strip off this is very difficult to strip off usually so hopefully
this groove is going to make it considerably easier so rum my knife down the groove take
my knife and move it round score round at the point of termination yeah
side cutters hopefully Joe that's gonna make it easier
to pull away still difficult yeah that has gone a lot easier I'll show you the other
one in a minute the original one so that was considerably easier to move that it's not
as easy as the standard PVC because of its properties Joe yep nice amount of French chalk
in there yeah now come to expect back from Doncaster cables after stripping those recently
house all good yeah so that was again from personal experience I can tell you that I've
that looked a lot easier than stripping normal low smoke zero halogen cable look I swap it
in for the three core one we've got over there without the groove and just just see if I
can find shows physically it's a little bit more difficult I can I guess so we've seen
the grooved cable in strips do you wanna have a go at this more standard and low smoke zero
halogen cable for us remember we're using the technique that we expect our learners
still know this there's an industry they tend to pull the CPC so we don't do that so before
you comment I'm just doing the same technique we asked our learners to I've scored round
here for terminating point actually the point of which we're going to remove off the mechanical
protection so I'm gonna use exactly same technique again gonna go in with my side cutters like
so and hopefully I can pull this apart so easy it's just sliding down there yeah and
of course you could you could have run your knife
you might not be cutting into a live conductor there you might have some serious issue there
down okay are in debt or even score it like we did before but there's no there's no indication
that where is the groove in the other one yeah just make sure that you kept just on
the CPC track effectiveness and again I like that technique and it weren't always trained
with but again with our students coming straight from school and trying to avoid them running
a knife down damage like that so I think I've got it going now there's gonna be there really
Gaz that's going
well how you made that look easy yeah effortless effortless various other techniques we know
that this is the one our learners would use yeah no sweat well I think I think we can
say that was a very conclusive demonstration wasn't it I think it's fair to say that having
that groove in the cable really does make life a little bit easier and yeah of course
having the most amount of French chalk in there as well allows that to come off really
well as well so I've got interesting