so for this wiring diagram we're going back to the one way lighting circuit we're going
to introduce a joint box this can be adapted now probably for more modern installations maybe where
we need to take the connections that were in a three plate ceiling rose and then we want to put
them into a joint so then maybe we can go off and do a series of LED down lights we use this as a
very basic job early on in the workshop in order to get the dressing of cables within a joint box
well our joint boxes at college tend to look like this older style one they're either white or brown
they're rated 20 amps for us just to give them a little bit more room
and we can see we've got our six terminals in there however i understand that there's some
there's some downsides to these especially if they work maybe under a floor we're obviously
going to screw this to the surface of a wooden board and therefore cable retention in other words
holding the cables within the actual box itself so we're going to probably use a 20 amp joint box
for practicing wiring them up and thinking about cables that aren't in light fittings or switches
however i understand in modern installations you might be using something like this
from insure okay from Ideal industries and maybe using it alongside connectors that are these
style here so these push fit style connectors within the actual box itself or lever ones
okay so that's the insure box we've also got this one the Wago box again we'll look at the
chord grips on these but you can make connections in there and it might be that you choose i don't
know Wago or depending on if you want to go for the German version Wago connectors in here so the
advantage of using these ones is obviously you get the cable retention so what i mean by that get the
ability to use this section here so if i just push that into there you can see it's held or gripped
that cable so it's held it into position likewise on the insure one if i just push that into there
temporarily you can see that that's gripped the cable and my connections can be dressed in here
so ideally at college we'd like to be thinking we'd use these style of connectors
but the likelihood is that we're going to be using this style of older style joint box and
you can see now the problem being when we lay the cable on to dress it round into the terminal
this doesn't have any retention but we end up putting a clip here on a wooden board to hold
it but of course that couldn't be left you know floating about with no cable retention
so that's what we're gonna have a look at here so we're still gonna be using
one millimetre squared PVC PVC twin CPC cable so twin two live conductors brown is
usually identified as line blue is usually identified as neutral but we'll see again
how we may identify the blue conductor which we're calling neutral in the workshop as a different
conductor in this and our bare conductor in the center which is our circuit protective conductor
remember it's bare because it doesn't carry current under normal conditions and will only
carry current from a maximum of five seconds under fault conditions to earth we will look at other
instances maybe in the future as you get to level three where the CPC might be carrying current
we also identify the CPC with green and yellow sleeving at its termination points and for
this cable being one millimetre squared all the conductors are one millimetre squared and they're
made of copper so we've got our wiring diagram hopefully that we're familiar with now we've got
our consumer unit remember the connections in here will be slightly different the line conductor on
top of the breaker the neutral bar and earth bar for our connections we've introduced a joint box
i've only got four terminals in it could be a four terminal one six it could be one of those
insure or Wago boxes a one way lighting switch so it's a one gang we've seen that before one
switch on it one gang and when we turn it over we've only got a common and L1 or two
terminals we should suggest so that's a one way switch so we've got a one gang one way switch
and i've got a lighting point here this could be a straight skirted batten lamp holder that we've
looked at in a previous video on identifying basic electrical circuits it's also going to be a short
video so in other words i've released one that's under a minute long just explaining that again
is what we could be using there it could be a ceiing rose and pendant it could be a standard
batten lamp holder it could be this style here straight skirt with just three terminals in it
it's probably in the real world going to be an LED spotlight or downlight whatever you
want to call it so what we're going to do is we're going to bring the cables into a joint
make some connections in here and go off to a lighting point of our choice it could go on
to several lighting points and we'll take a cable down to the actual switch itself
so if we start off as we tend to with our brown line conductor so our one millimetre square twin
and CPC cable our brown line conductor at the top of the breaker is going to come into the actual
connector so in here into this joint box so it could be again this joint box or one of these
and again it doesn't matter which of the terminals i use so if i was in this one it wouldn't matter
which of the terminals i used and if i laid it in here there'd just be a simple connector so
let's bring let's try and think which one logically is going to give me the best position
and we're gonna have a neutral so i'm probably gonna be stuck with this one here so i'll just
bring it up remember you'll be using a ruler or rule and i'm doing it upside
down so i'm gonna bring my line conductor up and i'm gonna bring it across into here
you would normally bring the conductor in this style of joint box here you'd normally bring if
you bring the conductor in say to this terminal you'd bring it past and back round so you come
in past the terminal and back round so in case it ever became broken you could short side it if you
short side it to start with you there's nothing you can do obviously in this style of connector
there's considerably more room to play around with with your conductors just floating about in here
so i would have normally brought the line conductor and gone round and back in i've
just shown it going straight in for this purpose remember that for the workshop if
you're using the joint box to get some clarity of laying out the connections in the joint itself
let's take the neutral next so we don't want to take this one to let's let's bring this one up
and i'm going to bring it into here that's my neutral connection so i've got my
one millimetre squared blue neutral and brown line conductor coming in my twin CPC cable
from my consumer unit it leaves me just the CPC and i'm going to take my CPC into this one here
so again we generally do it in green and lots of students like to identify it also with a
yellow stripe to make it look a little bit more like the CPC itself so that's our first one
millimetre squared twin and CPC cable coming in to our our cable joint joint of choice
so now what we're going to do is we've got to get down to here with our permanent line connection
and return it with our switching line connection and then take our neutral our switching line and
CPC across here if it is an LED light fitting it could be that needs all three it could be
that it just needs a line and neutral remember to look for the symbol for double insulation
so if you have a item with a box within a box and we've looked at in the workshop
on the electrical accessory it will not need the CPC in it and lots of LED down lights are
double insulated but we'll take it across to suit so we're going to take down here
again a one millimetre square twin and CPC cable okay this could be uh twin brown and we use a
lot of twin brown at Tresham college but in this series of videos i've kept it with brown and blue
that's a lot of colleges use brown and blue and a lot of industry used brown and blue down to the
switch but in this case when we're coming down to the switch we know the blue will not be a neutral
it'll be a switch in line return but let's start with the line conductor first this one's a
permanent line connection and we're going to bring it down into here so let's work out a neat way
of doing that so if i bring this one up here and i'm going to kick it straight into there so i've
got it into the same terminal so my permanent line comes into the joint down to the switch
i'll return on the switching line which could be brown if i was using twin brown but we're going
to use the blue conductor as a switching line so i don't want to bring blue to blue because
that would be neutral to switch in line so i've got the other terminal here which is going to be
my switching line one so i've got a choice now i'm going to neatly make this connection so if we come
if we kick that down and then bring this one out slightly and we bring that all the way down to
there we've got our switching line conductor in our cable now so that one's our switching
line and we know we identify that at both ends with a piece of brown sleeving
on each end so that's the brown sleeving so there we go so we've got some brown sleeving on there so
that would be slid onto the blue conductor cut and identifying the blue as a switching line
conductor and not as a identified neutral we've got our CPC as well so we're going to bring that
through as well so let's see how we can do that reasonably neatly so if i bring my green conductor
up i'm just going to kick it across into here and that's got my CPC wrong colour that was close Gaz
so keep my yellow one and just give it a little strike of yellow
that's my CPC remember lots of the boxes in the workshop that we use are both plastic switches
and a plastic box i know some colleges do end up mounting metal boxes on the wall because they
last a lot longer and there is a terminal in the back there for the CPC there's also a terminal
in the back of the plastic boxes that we're using at college which really comfortable with
which is obviously to support the CPC as well so there we go if we've got a line comes down to here
we operate the switch a switching line comes back and we've got a CPC that carries through
and at the minute we've got a neutral that's left in our joint itself that means this light fitting
here whichever one we select straight skirted batten lamp holder LED etc is going to need a
neutral and a switching line well remember we're using this cable here so that would be
switching line now as brown and blue would be neutral on our CPC so this is where we started to
think this is what my students who start thinking about the colour of conductors and what they're
doing so whereas the blue one coming down to the switch was actually a switching line and the blue
one coming into the joint was a neutral now when we take this cable across the light fitting itself
we've got brown a switching line which goes across which we connected to the blue with brown sleeving
we've got blue neutral with blue neutral and our CPC so that starts becoming two browns here
one brown one blue and the blue's got brown sleeving and two blues here and obviously
our three CPC's a lot to think about and consider might be worth in a minute just pausing the video
and just contemplating those connections we're going to make so this cable here so let's start
with the brown conductor we'll come across maybe just be connected to our LED fitting
our blue neutral comes across and then we bring our CPC if required across depending on the
fitting itself into here so there we go so that cable now comes across as switching line circuit
protective conductor and neutral across to our actual fitting itself it might be that you want
several fittings to come on together okay so you might want this stay as an LED downlight and then
several maybe 8 10 whatever you're wiring so that would just be a simple case of doing the following
you would just come out of here with a switching line you would come out with a
neutral connection and a circuit protective conductor connection out to the next light so
the next LED light and then again and again and again just repeat that process so when this lamp
comes on it will share a switching line neutral and CPC to the next lamp so when this one's on the
next one's on etc so you can have many points on at the same time control from one switch
you might have that sort of arrangement in the kitchen you walk into your kitchen there's one
switch and it turns on eight downlights in your kitchen that's what's happening with the
switching arrangement and it might be that there is a joint somewhere near the first light fitting
in order to make connections very similar to this we're working towards wiring LED lights in our
electrical workshop and understanding this process and we also looked in previous videos about
feeding the switch which is a different method of this and i might go on and do some drawings
of those in the future but there's definitely videos in something called the two plate method
so again make sure you go and recap those it could be from here as well from this joint here which is
maybe the kitchen lighting area we might want to bring out a cable that goes into the next room to
feed it so you could find you're taking out a permanent line connection a neutral connection
and a CPC which now goes off to feed the next room so that would then take those in
and we might end up doing something like this
where we have this cable here is actually coming out this joint box okay and as it
comes into this fit and we have a three plate method that was the first drawing we looked at
okay so that could be what's happening that you're taking that neutral permanent line and CPC
out of the joint box into the next room that goes into loop neutral goes into the neutral connection
and the CPC goes into the earth terminal within the electrical accessory itself and we go again we
could extend this so there's nothing stopping us now changing this to work it as a two way lighting
circuit or a two way intermediate lighting circuit as we've looked at in previous video presentations
so if we look here this cable coming down here is our permanent line switching line and CPC
we could easily change this for a two way switch and we could add a three core in as we've done
before and make this two way these lights these many LED down lights and we could also go on and
do the same if we wanted to because that's just the cable coming down to this switch here we could
add two way and intermediate and again we've done those series of videos and if you've understood
the first three in this series you'll understand how you can extend just with a simple cable that
comes into your one way switch which we've got here regardless of the method how you can change
that and do two-way two-way intermediate etc so that's used in the joint box method
something we've used in the workshop but you might find a connection like this may be made near or
within the enclosure for an led downlight and then of course you go and wire extra led downlights in
that area so this method may come up in this form in the real world it may use these boxes here
that we've looked at before in order to make the similar connections to what we've done here
so as always this video on the wiring diagram for a joint box i hope this video has been some help