in this presentation i am going to try and show you the skills required in order to sink a cable
into a plaster and block wall and otherwise we're going to chase out the fabric of the building
in order that we can facilitate the cable behind the surface and install either a single or twin
socket box so that flush boxes could be those for a lighting point or a single or twin socket the
skills are exactly the same in this presentation for whatever we are chasing into the wall
so already we can see that during the first fix the cables been left
and the wall now needs to be chased out in order to install it behind the plaster wall itself so
we have to chase out the plaster finish as best we can without damaging too much the surrounding
areas it's usually not the responsibility of the electrician to reinstate it but it could be
therefore we want to leave us as a little over damage as possible so I only take out
the area required during the chasing process so we will chase that an area down the wall
to facilitate the cable and the cable needs to be further protected by a PVC capping in we'll
show you how to fit that and we're also going to chase out a single socket box I'm just going to
put a random height on this wall this wall can be used many times by learners so we're trying
to limit the amount of space that would be take it out however the skills required out there in
industry exactly the same just perhaps the chase would be a lot longer down the wall in
order to facilitate the socket outlet or lighting at the correct point so first of all I'm going to
offer my clapping up and I'm going to make some measurements and marks against the side of it
in order that we can start the chasing process along with the single box as well
so often my capping up against the wall
and I'm going to take a thick marker pen and mark down both sides
both sides
the reason I like the line to be thicker and rather use your pencil a thick pen and pen in
this case is because we tend to chamfer that in slightly when we chase and therefore once the
the plaster and brick alone has been removed we find it doesn't fit so by having the lines
wider than the actual capping will actually make the chase that little bit bigger
and hopefully that'll remove the narrowing of the chase as we go exactly the same on the box
take my single box at the required height for the installation mine is at random point
in the cubicle here at college and again I'm going to mark around that using my thick pen
so the area for facilitated my capping and cable marked out and the area around in
this case a single socket box has been marked out taking the same process if it was a twin
or whether it would be a lighting box as well so during the chasing process I'm going to be wearing
a pair of goggles I should also be wearing a dust mask in my workshop as well however for
part of the presentation or may not be wearing the dust mask used in fact I want to communicate some
information to you and I've struggled to overdub the voice before when I further incorrect on the
video so if I'm not wearing the dust mask is it because it's not required in my workshop it is
is purely to transmit the information across to you I will also need to be using my lump hammer
a cold chisel and my bolster chisel during the chasing processes so first of all want to do
is break the finish of the plaster all the way around the line that of mark so I'm not going to
absolutely wallop the living daylights out of here in the first part I'm just gonna break that finish
on the actual plaster itself and then we'll go in a little bit firm once we've been round and
broke into it that first time so let's see how that looks so using my bolster chisel
so what I've done is broke the top finish on the plaster some parts have come away but
at the moment fortunate for me it's only come away in the area that we're going to remove
and has come away on the surface that we'd like to leave as reinstated as possible so fully plastered
if we possibly can these sides bits may fall off during this process but at the moment we're only
lost the bits that actually fall within the chase itself so next I'm going to chase out the area in
order to facilitate the single socket box to do this I'm gonna start on one edge in this case
the left-hand edge and I'm going to chase that to what I believe is the correct depth for the box
then what we're going to do with that area cut to the correct depth on one side
is chase into the area which we think is at the right depth so we'll start here and in chop to
the gap that I've obviously created on the first part of the chase so see what that looks like
so
hopefully this left-hand edge here is that the depth that I believe the box is so in other words
I've gone down for that depth and we're going to
now chase into the part that we've actually started so into that groove
now and I'm just checking down that exactly the same depth as that first corner that I stayed on
now I am tidying up the edges what we came to do is chamfer down slightly
so I'm just squaring this top edge and the side edges
out in order to facilitate the box so they tend to be what we curve inwards
see if the box fits
what we have found there is tiny bit of play which is not a problem but is it flush chisel
and hammer down so hold in there it's below the surface so some slightly below the finish
of the plaster in order that we can reinstate to what we don't want to do is have it sticking out
it's got to be flush or slightly below flush of the surface that's not the even further
or dead flush where we are so box done repeat the process now for the actual chase yourself
to facilitate the cable and capping I probably don't have to be quite as deep as I was for the
socket box itself so as I take this one out I may keep offering up the cap in to see if I've got it
below the surface so just sunk it in slightly below that surface certainly same process as we
did before but perhaps this time I'm not going to be cut into an edge I'm just going to be chasing
it out as we go along as I start and got across start and go across and one the way up the chase
you can really see we're popping out bits of the plaster well we don't want to do
this great be correct lumps of plaster to be missing these are just popping off as we go
not a lot we can do about that we have got to chase it out in order
to get cable under it so we're gonna have some peripheral damages we go
you
would see how we are working up there making sure we keep the width okay you know keeping
the corners clean as well so I'm going back in and making sure I'm chamfering that I said tends occur
I'm gonna carry on this stop the video there will see it when the chase is actually finished
so we just need to confirm as we did with the box that the capping sits in the chase
and doesn't stick out build the surface in other words protrudes we lay it in there
we can see that the cap in itself is below the surface of the finished plaster and we've only
lost a little bit of outside plaster here that will obviously need to be patched as well as the
chase but them quite well by using that technique of just breaking it in the first instance that we
went all the way around before we go in solid and hard with our chisel in order to remove
the plaster and block in this case it could be brick but in this case its block now we're gonna
have to do is take a little bit more out when opposition my single socket box into position
the cable is going to enter here in this top hole but is it blocked by this corner of brickwork here
and obviously the box and doesn't crush against the top surface so I'm going to need to take a
little bit more out so i am going to use the cold chisel for that rather than the bolster
chisel for that area there so let clear the brick dust at the bottom
on my single socket box it's in an area now that the cable can lay in and comfortably get into the
pre formed hole in the top of the box it or knock out in a moment someone do now is not
the hole out in the top of the box it's a 20 mm hole and I'm going to put a
20 mm open grommet in its place in order to protect the cable
knock it through with side cutters break it out and we are in position in my grommet
the box itself just protect the cable where it enters the metal enclosure to me position like
so I've an option now fit the box or I can dress the cable around fit the capping in I'm going to
choose to fit the box next I've got my drill set up with a 5.5 masonry drill bit I've also got
around head screws because we're fixing a metal box everyone in industry is now laughing at me
because only use countersunk at college while we're fitting on metal box our default position
is first of all the screws themselves on round head that's what we're using this demonstration
so now I didn't have it on hammer action this is a thermal block wall didn't require hammer to go
into a concrete block or brick it wouldn't need to be set to the hammer action or maybe even be using
an SDS drill rather than a standard battery drill with hammer action only next up gonna put the
plastic wall plugs into position put those into the pre-drilled holes and then we'll screw our box
into the position as I said using round-headed screws and a pozi drive screwdriver for us
we're using one and a half inch screws here at college because we're on a block
wall in order to get a decent fix
in place once the box is in place we can look at dressing the cables down the wall and placing
the cap in over the top box fitted next ones are capping dress the cable down and hold the cap in
on using galvanized nails as well because we don't want it to corrode through once the the finish has
been added to the chase that we've taken out so what boxes they're gonna take my capping and offer
it up into position it going to stick out slightly at the top and I'm gonna make a mark at the bottom
we take my side cutters we cut to one side
the other side break it way and we see it's you appropriately length and now I need to dress
my cable down the wall for a similar of dressing that we've done when we were working
with cables on one of the boards so take out all the bumps first so plenty long enough
set into the box leave a little hump on the top and just dress it into position
capping on using using galvanised nails probably in the find a
couple of the the top area company the bottom area should be enough to hold it
edges using galvanized now so don't rust back through the plaster the cap it is really there to
prevent person reinstating the wall from damaging the cable
moving up and down it moves freely that means I haven't pinched it
with nails would be worth looking if you hadn't it didn't move freely now
I've second capping now I'm just checking your not nailed into the cable
you know it's now ready for it to be replastered probably enough to trim this back to length
so we can curl that into the actual box yourself
allowing for the over plaster filler whatever they decide to put in as a backfill into the chase
itself would be probably a browning or basic coat first followed by finishes as it was original was
okay so that's the chase wouldn't matter if we've gone for a twin box or a shallow box for
a lighting circuit the techniques are exactly the same key things to remember is that initial just
nipping round the entire chase of the box to break the finish just to give it though before we start
hitting it too hard and when I chased out the box itself I started at one side and chased the
actual side that I believe was at the right depth hopefully that's been some help