so we're going to continue looking at wiring diagrams for light and circuits in a previous
presentation we looked at a one-way lighting circuit you walk into a room there's a switch it
turns on the light in the room we're gonna extend that now to two-way switching so we've got two
positions of which we can turn on the light this is common for bottom of the stairs turns on the
landing light you walk up the stairs to go to bed say you can turn off the landing light from
a switch in a different position from two ways so we've got two switches on here remember these
will represent the connections within a two-way switch as will the ceiling rose or batten lamp
holder here remember from the first presentation the connections within the consumer unit won't
exactly look like it does on the drawing but shows us the fuse the neutral link and the earth
connection for the CPC's so let's have a look at what we've got then so we've got two two-way
switches so you walk into a bedroom you turn on the light you walk to another position and you
can turn off that light okay so you've got two-way switching the wiring that we looked at previously
for a one-way lighting circuit here is very similar from this section here up and this section
here down all of these sections here are identical what we're going to do now except we won't have a
one-way switch here we will have a two-way switch so this is a two-way switch there's one gang so in
other words there's only one switch on it but as we look here we can see it's two-way there is a
common and L1 and L2 as well it doesn't matter I could have turned it round it's common L1 and L2
it's only important that we get the commons correct and we'll look at that in the drawing
L1 and L2 can flick as they go between them but students tend to like to keep them in the same
place but you don't have to so this is a one gang two-way switch and we need two of those
and as before we've got here the base of a ceiling rose or pendant so again exactly the same as we
had before we've got that base with two terminals here for switching line insulated away from three
terminals here for the loop and then insulated away from three terminals here for the neutral and
a connection for our circuit protective conductors likewise here exactly the same setup we've got
two three three and a CPC connection as well so that's what we're going to be looking at we're
looking at how we're going to make our connections for a wiring diagram to help us do two-way
switching of a light fitting we're going to be using again pvc pvc twin and cpc cables so I know
in the past college I have used twin brown and I talked about it in the first video
down to the switches but i'm going to keep it using twin and cpc so we've got a brown a blue
and a circuit protective conductor which will identify the drawing with green and yellow to
identify the green and yellow sleeving that would go on top of that for identification purposes
it's one millimeter squared at my college it might be 1.5 in the real world
remember we're chucking this cable away after each of our lighting circuits so we might as well took
away one mm cable rather than 1.5 we're going to introduce a new cable as well so we're going
to have to use this cable here this being a three core and cpc so we've got brown black and grey so
we need those colors for our drawings as well and a bare conductor again which will be identified as
our circuit protective conductor so let's do the first part which I said was identical to
when we did our one-way lighting circuit so if you've got a one-way lighting circuit in a room
you can easily turn it into a two-way lighting circuit by simply adding one more cable between
the switch so if you had a switch at the door and you wanted to put a switch somewhere else
into a bedroom you just simply put a three-core cable between the two and change the original
one gang one-way switch for a two-way switch that links in with the first video we looked at
remember i'd expect you to be using a ruler i'm doing it upside down and obviously i'm
doing it freehand but i'd expect you to use a ruler we'll start with a line connection here
for us it's coming out of the consumer unit so at the top of the circuit breaker it could
be and we talked about in a previous video it could be coming from the next room it's still
going to bring in the same connections so we're going to bring in a permanent line connection
and we're going to use any of the three here in the center loop make it easier from a drawer
and i'm actually going to use this one here on the end so i'm going to just pull that one down
and then we're going to bring the two together remember i'm doing this free hand I expect you to
use a ruler so that's brought our permanent line connection into the block of three in the center
which is loop these are not connected to the lamp remembering the lamp itself will have a neutral on
one side and a switching line on the other side and we won't want a permanent connection to the
line to be across the lamp because the lamp would illuminate all the time so the cable is a pvc pvc
twin cpc we've used the brown so it's used the blue in this case which is a neutral so let's
bring the neutral in so i'm going to take it out this one here i'm going to bring it from here
and then we're going to bring that one across to join those two up so we've now got the neutral
connection coming into the block of three marked with an N in our ceiling rose or pendant so we've
got the block of three there for our neutral okay we've used the loop terminal for a permanent line
and we're now going to bring in the final connection which is our cpc so from the consumer
unit to here we talked about in a previous video didn't we that the cpc isn't really required for
these type of light fittings because they are fully insulated they're all plastic but
we know light fittings can easily be changed for metal ones making them exposed conductive parts
just putting a little striking line down the side there so it's actually green and yellow
it's only one cable remember that's not two cables that's just trying to show the outer green and
yellow sleeve in okay that's what we're trying to do there so that brings our first cable in so
it's come from the consumer unit line neutral and cpc so line neutral and cpc is brought in like so
and it's connected into the loop any of the three it doesn't matter which one into the neutral okay
any of the three doesn't matter and into the terminal which is for the circuit protective
conductor like so here remember fully insulated but it can be changed from metallic fitting which
is an exposed conductive part in the future and a cpc will be needed so that's our one millimeter
squared cable coming in identical to what we did in our previous video so when we looked at our
one-way lighting circuit we did exactly the same and then we took a cable down which
was also one millimeter squared which had brown blue and a cpc we're going to do the same again
start by doing the cpc so we're just going to bring cable down here so we're going to bring
down our cpc like so again some of my students do like to strike a little yellow down the side
so our cpc comes down we're going to bring down our permanent line connection so the permanent
line coming out of the loop there's two terminals left okay doesn't matter which one I choose i'm
going to bring down my permanent line connection and it doesn't matter whether it goes in L1 or L2
so as we look at our switch we've got it here we've got common
on its own and L1 and L2 okay so we've got common we've got L1 and L2 it doesn't matter
which one of those two it goes in as long as it doesn't go into common so for ease of my drawing
i'm just going to bring this cable out a little bit that way and just bring that line up into
the loop so i've taken one down into L1 or L2 so that would be my permanent line coming down
we said didn't we that the next bit gotta be really careful of because this is not
a neutral okay this one here is not a neutral okay so i'm going to bring this one which is
blue coming down to the switch is actually my switching line so i'm going to need to bring that
down correctly so my switching line comes out of here like so so I can bring that down there
and I can bring it across and into there I could have had these two the other way around
doesn't matter it's just showing the cables coming down permanent line comes down
and not a neutral we looked at it before we said it was switching line so this cable comes down
here to the switch with permanent line cpc and switching line we must put on some brown sleeve in
in order to identify that not as a neutral but as a switching line and we do that simply by putting
a little bit of a brown tag on the drawing in each of those positions
okay so there we go we've got those so now we've got to work out what cable links that two
two-way switches together and that's going to be this one here this is our three core and cpc
and again you can see only one of the conductors is brown we've got
black and grey and the two that we are using for switching line conductors being grey and black
will need identifying with brown sleeving and of course green and yellow sleeving on our cpc
so if we have this cable coming down here as we would in a one-way switch
so exactly what we've got here we had a blue brown and the green and yellow coming down
to a one-way switch in the real world all you need to do is leave that cable in place
take off the one-way switch and replace it for a two-way switch making brown and blue with blue
blue with brown sleeving in L1 and L2 and then just introduce a three core from the switching
position you've already got to a new switching position so that's what we're going to do here
so this is just simply one cable from the switch to the other switch three core and cpc
so we need to find the right colours so I need a black pen I need a black pen I need a grey pen
and I need a brown pen so let's start with the grey okay it doesn't matter which one I choose
but i'm going to come out of here so i'm going to bring my grey conductor to link this one to
this one here so i'll just take that down to there and that's my grey connection
and then what i need to do is identify it with brown sleeving both ends like so
my black's going to link my two commons together this is the important one to link
my two commons together so the black will come down and link my two commons together
and again we identify that with a bit of brown sleeving on both sides okay like so
and then the next one of the three core this brown one here is going to connect to the brown of the
twin and cpc cable if you imagine that comes down as a permanent line connection and then strikes
onto the brown one meaning that that will always be connected to the permanent line connection so
that's why I always make that one brown so bring that one down as well like so and that
has introduced my three core cable just gotta now make sure I put the cpc in so I bring my cpc down
and again some of my students do like just strike the side of that with a
little bit of yellow so what we've done there is just simply had the original one-way switch
maybe and we've changed that now for a two-way switch and this one here is a two-way switch and
all we've done is introduced one more cable this cable will be in a three-core and cpc
we've put the permanent line saying L1 or L2 doesn't matter which the switching line
okay which we had before in L1 or L2 it doesn't matter which but it's important that we linked
our two commons together we kept that as black and we had the brown strapper and the grey strap are
coming down as well so these are sometimes called strappers so let's follow the circuit through
see if we can work out where the light fitting is on so my permanent line connection comes
up into the looping terminal it comes down to here it goes down here but look at the blade it also
goes down this blade here and the line connection is connected to this one here this blade here and
up this grey one here onto the switching line here and yes in that position there with the two blades
as they are now this lamp would illuminate so this would be illuminated at that stage
how do I turn it off well if it's on it should be it doesn't matter which switch you turn
so whichever switch you operate it should go off so let's let's move this one fictitiously
into the other position so it's going to come across to here so it comes permanent line comes
in through the loop down here well this blade now is over to here so it only goes down here
and this blade also is open so it doesn't turn it on okay in this position here we can see it's
on if we turn this blade and this blade so i moved this one across and then this one across
we can follow the line through down here so this one's across over here would come down here
this blade would be over it would come back at the common remember this blade would be over
and the lamp would illuminate so these two bladed positions if it's off and you operate
one of them the light will illuminate if it's on and you operate one of them the lamp will go off
and therefore will not be illuminated exactly the same as before we can extend the circuit through
so if this was in say bedroom number one and you wanted another light switch in bedroom number two
you simply need a permanent line neutral and cpc to go through to the next area
so at the looping terminal we take a permanent line through
we take a neutral connection through to the other area and then we can take a
cpc connection through to the other area and repeat the process again
let's just put that line on there so that would go into the looping terminal that would go into
the neutral and that would go into the earth terminal where the cpc is secured and you can
do a one-way lighting circuit or a two-way and we'll build it up to be two-way and intermediate
so that's our wiring diagram for our two-way lighting circuit two positions
in order to turn on our light fitting as always I hope this video has been some help