so in this presentation we're going to look at the wiring method for wiring lights up
when they're installed in conduit the method is different than the one we've looked at
previously in our three plate loop in method using pvc pvc twin and cpc cables so when we
employed this type of wiring system often used in domestic dwelling we had an additional terminal
in our batten lampholder or ceiling rose and pendant the centre loop in terminal was present
in this system employing using single insulated cables so we've now got single insulated cables
for a conduit system and the mechanical protection being provided itself by the conduit so just
thermoplastic pvc insulated cables we can take our conductors anywhere we like within the circuit
and we're not stuck with other conductors within the actual construction of the cable
so in singles we can wire our conductors anywhere we like and therefore the method of connecting and
wiring our lighting circuits is different to that than employed in a domestic dwelling also
what is different is the fact that we're using 1.5 millimetre squared cables as our smallest
conductor when we were wiring our lighting circuits in my workshop in pvc pvc twin and
cpc cables we did use one millimetre squared cables we don't in conduit the other difference
is also now they're stranded copper they are not solid conductors so they're 1.5 as a minimum and
they are stranded the reason being is give greater flexibility therefore they're stranded as they're
being pulled through the conduit system itself and they found that one millimetre squared cable as it
was being pulled into the conduit system could tend to stretch slightly so the minimum being
1.5 and the construction being stranded copper because we can take the conductors anywhere we
like in circuit the back of our batten lamp holder and this is a straight skirted batten
lamp holder only has three terminals one in which will incorporate the neutrals one which will have
the switching line conductors and one for the circuit protective conductors we no longer have
the loop in terminal in this method so let's have a look how we're going to wire in plastic conduit
in this case it could be in steel conduit a lighting circuit using the conduit loop in
method where we can take our conductors anywhere we like in circuit let's see how we're going to
wire a simple one way light switch and lighting point so we've got a pre-tubed exercise board of
which the first stage i'm going to ask my learners to do is have this one way switch controlling this
light and then extend it to say second office where there's a one way switch controlling a
light one way switch controlling a light so we're at stage three so we're going to practice the
conduit looping method and build it up in three individual stages normally we would be pulling
the cables in using a nylon draw through tape one end is which i call the mouse and then an eyelet
on the other end of which we attach the cables and we've discussed in the classroom how far we could
pull a cable system through the conduit before having to withdraw it from a box and re-pull it in
however because our conduit system is so small we're not going to use the nylon draw-through tape
in order to wire the circuit we're simply going to push the conductors in but be aware that we
should be using one of these in industry also as we're learning we're likely to be pulling
one conductor in at a time again we discussed the the need to pull several conductors going through
one distance through a part of a conduit at the same time to avoid friction across the conductors
whereas we're going to pull one conductor in a time to work out where they've got to go as we
try to underpin the learning done in the classroom and some drawings that we've done
however we know that we should be pulling conductors that are going in the same direction
through the same piece of conduit all at the same time to avoid them passing each other
and causing friction and possibly burning off the thermoplastic insulation around the conductors
let's go and look at seeing if we can wire one way switch here
and a light fitting here from our consumer unit here using the conduit loop-in method so stage one
one way switch here controlling the lighting point here fed from the consumer unit here
we start off with the neutral conductor the neutral only needs to appear at the lighting point
itself so we're going to go from the consumer unit with our blue neutral to our lighting point itself
to make it a little easier for us to wire through the conduit system prevent it catching at the
adapters and boxes i'm going to fold over the end of my cable giving it a better chance of
popping its way through gravity falls so i'm going to come from the lighting point
down to the actual consumer unit so neutral needs to be at the lighting point itself
we're going to pick that one up from the consumer unit in the first light on the circuit
making sure we leave ourselves plenty of cable at termination ends so we talk about at least twice
uh as long as the consumer unit itself and our neutral point is our lighting
point here and again leave ourselves a little bit of spare of termination so
from the consumer unit we've gone to the lighting point itself with our neutral conductor
now we can look at wiring the cpcs we've talked in the classroom about limiting the number of
cpcs in the back of our straight skirted batten lamp holder it will facilitate three or four cpcs
but at this stage of our learning to make it easier i'm gonna try and limit it down to only two
cpcs in the back of the straight skirted batten lamp holder with that in mind from the consumer
unit we're going to take our cpc directly to our switch and then from our switch back to our batten
lamp holder the other advantage of wiring it this way it does make in this case there's only one on
the circuit the final point here on the circuit will have only one neutral one switching line
eventually and one circuit protective conductor and again i like that so the cpc is going to come
from the consumer's unit directly to the switch and from the switch back to the batten lamp holder
again i'm going to fold over the end i'm going to work it back in reverse
so cpc goes in it's going to come all the way down to the switch itself fold over the end
so first part of this cpc from the consumer units gone directly to the switch
and then from the switch we're going back up to the light fitting itself so i'm going to come down
because gravity falls making it a little easier and pull the cpc through and cut it off to suit
so the cpc comes from the consumer unit in this case we went straight to the switch and from the
switch back to the lighting point the lighting point also has a neutral from the consumer unit
the neutral went straight to the lighting point itself we've now got a look how we're going to
get a switching line to the actual light fitting here let's look at that in the next part of the
presentation so this time we do not need the line connection to come from the consumer unit directly
to the actual fitting itself because we have no facility for a loop in terminal here unlike
when we're wiring domestically so our permanent line connection will come from our consumer unit
go directly to our switch and be connected into the common terminal and then from L1 a switching
line conductor will come back to the light fitting itself so let's do that next so again fold over
the end this one's going to go directly to the switch be my permanent line so from the
consumer unit directly to the common terminal of the one way switch will bring my permanent line in
and then from my switch from the switch going back up to light fitting my switching line conductor
and again that will be connected in L1 fold it over the end we'll drop it down
again because it's easier to push it down than it is up we'll come through
and our circuit is wired so at the lighting point itself we only have
one neutral one switching line and for us to make it easier one circuit protective conductor at the
one way switch we have a permanent line from the consumer unit a switching line back to the light
fitting and two circuit protective conductors so that's the conduit loop in method we can take our
conductors anywhere we like and we did we took the neutral directly to the light fitting we took the
permanent line connection directly to the switch from the switch we took a switching line conductor
back up to the lighting point our cpcs could go in any order we wanted but we decided to make
life a little easier in the skirted straight to go back and land holder by bringing the cpc
first to the switch and then back up to the lighting point itself and also what i like
is the fact that there is only one point on this circuit at the moment but if this was the final
point on the circuit one neutral one switching line and only one circuit protective conductor
let's see if we can extend that circuit in the next part of the presentation
so we're in a position where office number one has a one way switch controlling a lighting point and
we don't extend it now into the second office so we have a one way light switch here controlling
the lighting point here first of all we must get a neutral to our lighting point our closest neutral
is here so we're simply going to take a neutral from here across to here let's do that next
so push my neutral across and we have a neutral now in the second office the
circuit protective conductor we're going to need a cpc both at the lighting point and the switch
and we said previously i'd like to make it easier and have fewer cpcs at the lighting point itself
so i'm going to come from this light i'm putting down to the switch and from the
switch back to earth the lighting point itself then fold over the cable and push my cpc in
go down in length down to my
light switch itself
and then back from my light switch up to my lighting point
okay so we have a cpc now at the lighting point and two cpcs at the light switch itself so we took
the cpc from here down to the switch and from the switch back up to the the lighting point
trying to reduce the number of cpcs in order to be easy to connect connect them into the straight
skirted batten lamp holder we now need to work out where we can get a permanent line connection
into the common terminal of this switch we could suggest that we come from the consumer unit but
it's impractical to have say 10 coming out the top of a circuit breaker in order to do 10 different
offices the closest permanent line is at the common of this switch in this office so we're
going to come from the common here so there'll be two in the common both of them permanent line
connections so they're common from here so line from this common across and down to this common
at this switch here so this is where we got a little bit of variation in the wiring system
compared to looking at a domestic dwelling we've got the flexibility of picking our connections up
from wherever we need them so the permanent line is here so let's pick it up from there
so another conductor down here now it's going to start to get a little trickier to get them in
so this one here and we've got to get that all the way down to our other switch
through we go and down we go so we've now got a permanent line to be able to be connected at the
common terminal hopefully let's try that again so we're going to have a permanent
line now down at the common terminal of this switch in office number two
so there she goes so permanent line comes from common here over to common here and we just
simply need a switching line to return back to the lighting point itself so let's do that next
so from the light fitting we're going to come down to the lighting switch itself
okay so we've got now office number one and office number two both one way controlled
by the switches within the rooms that they are simulating so let's recap them for
the second office we needed a neutral at the lighting point we took it from the
the neutral in the previous office we came across we need the cpc in this office so we took a cpc
from the batten lamp holder down to the switch and the cpc back up to the lighting point a little bit
now thinking involved we needed a permanent line down at the switch we got it from the permanent
line which will be the common connection of this switch so we took a cable up through and down to
here and then from L1 a switching line back we can repeat this process as we move through
to office number three this switch controlling this lighting point so we'll do the same again
neutral will come across cpc will go down to the switch and one back to the lighting point
from the common through to the common to link the two permanent line connections switching line back
up to the light and lighting point itself ignore this switching position it's increased i want to
create other switching positions as we move forward so that's us looking at the conduit
looping method doing one way switches i hope this video has been some help