so if we start off with uh securing the conduit system so in this case it's been a black enamel
conduit system here i've made this about 18 years ago when i first came in to teaching i'm going to
leave it behind but it illustrates the different styles of fixing to a conduit and under an old
City and Guilds exam it used to suggest why you would use each of the fixings here of these four
so we're going to still run through that i still talk about that in my lessons previously when
i was teaching at Tresham college itself so what we've got here then i'll try and keep it in camera
so try and keep it in shot so what we've got here is from bottom to top different fixings and the
fixings mean how close it is to the surface in each case obviously it's a piece of wood
but there is a reason why we would be using each of these so we've got in this case here just a
plain saddle so it's just really effectively the front of a saddle they're all saddles but all
different types this is a plain saddle and the thinking behind that maybe move around this way
thinking behind that was it kept it very close to the surface and the exam question in the old
days you say when would you use a plain saddle a plain saddle would be used when you're on a smooth
surface like wood so that's a plain saddle there so we move along to this one here this one here is
a traditional saddle here's a galvanized version of it okay this one being black enamel so that's
a spacer bar saddle you undo the two little screws on the front those two screws and the saddle front
comes off you secure the back of it so you secure the back plate onto the actual surface and then
tighten the two screws up when you drop it on so we're using the workshop so we've got a space
of our saddle here so what's the reason behind using a spacer bar saddle it raises it slightly
further off the surface the reason behind that according to an old exam question was where you
had irregular brickwork in other words a brick wall would never be perfectly smooth to allow for
irregularities in it you'd use a spacer bar saddle moving along to the third one this is now bridged
it even further off the surface so we're a little bit further off now this is a distant saddle
okay so you can see that it's a lot higher off the actual surface itself the distant saddle
the distant saddle would be used where the wall is damp so it creates a larger gap here meaning a
film of water wouldn't sit in here so in order to bridge it off a damp surface the old exam
questions used to say you would use a distant saddle and the very last one here he's got the
biggest gap so clearly you can get my finger under the conduit itself and this saddle here is called
a hospital saddle it's slightly different in shape it's certainly raised further up and
you'll be expected to identify these in exam by pictures and making sure you can see it sprays
out the ends here they exaggerated on the actual exam question this is a hospital saddle so what's
the thinking behind that my students usually say well it's in a hospital well that's not the case
because when i walk down the corridor to find the Costa coffee in a hospital i don't see the
conduits in the corridor secured using hospital saddles but they are used in parts of hospitals so
areas of high hygiene maybe in the medical theatre maybe in the mortuary maybe in the canteen areas
that you'd need a saddle that bridges it off fur enough in order to allow a cloth to go underneath
in order to clean the conduit itself i wouldn't recommend the conduit in a hygiene area was this
style of black enamel but we would be the thinking behind it is that in order to bring it off further
we would use a hospital saddle for areas of high hygiene food manufacturing etc so there are four
common fixings so if we turn it around this way we've got plain saddle smooth surfaces spacer bar
saddle irregular brick distant saddle where the wall or surface is damp and then at the bottom
hospital saddle for areas of high hygiene we also talk about the crampet we'll talk about that one
in the classroom as well and where we use that as well as a girder clip but the four common saddles
are the ones i need us to remember in this part of the presentation so let's put that back down
conduit finishes this conduit finish here this conduit finish here is black enamel very very rare
when i first started teaching 18 years ago all the conduit systems that i put in were in the workshop
in black enamel it is a steel pipe covered in black glossy paint and you might not be able to
see but over the years that paint has started to remove and it's actually pitted out it started to
corrode so with the conduit system black enamel whenever you scuff it you must be repaint it in
order to prevent corrosion so that's black enamel we've got the commonest conduit now that we tend
to use we use it inside and out but the exam questions we'll talk about it for other reasons
this is zinc galvanized it's not galvanized conduit it's galvanized with zinc and the
exam questions will say in order to prevent corrosion of a conduit system what do you
do you add zinc to it in the zinc galvanizing process so we've got black enamel zinc galvanized
the third one on the table here it almost looks like chrome isn't it's stainless steel
stainless steel conduit quite expensive again this would be used in areas of high hygiene
in food manufacturing and processes where there's a lot of cleaning down of the actual system
itself so we'd be washing this down regularly we'd be using it in those areas we'd be using
stainless steel there is a fourth one in my note called sherardized sherardized is similar
to the galvanized but the zinc is actually impregnated within the actual steel itself
and not just coated on the surface we'll cover that in the classroom that would be sherardized
so black enamel conduit we'd use that inside in dry environments according to the exam questions
very rarely used now when would we choose zinc galvanized we choose it where the area is damp or
maybe on the outside of a building but certainly not on the outside of a building somewhere like
um the seafront at Blackpool because obviously the salt air would be corrosive into the galvanize
that's maybe where sherardized comes in and we'll cover that in the classroom
and again stainless steel we'd use that in areas of high hygiene that's
food processing factories etc so there are three common shared eyes being the next one up
uh we've got two different types um what we've got to see on that one maybe not too easy on that one
let's see if that one right i'm hoping now you'll be able to see if you can't see it now you'll see
in the classroom there is a line that runs down the inside of here it's probably about there
that's a line if you can't see it you'll be seeing it in the classroom if not if you're not in one of
the threshing lessons have a look at the end of your conduit and you should see a line running
down it that's because this is seam welded so in other words it was a flat piece of metal rolled
into a tube and welded and that's the most common so the most common type is seam welded
steel conduit they do do a solid drawn one solid drawn one wouldn't have the line coming down it
it'd be pulled or extruded from one piece of material so it would have
no line so what's the difference just quickly for this video we explained more in the classroom
if you needed a gas tight installation one where there's atmospheric gases like
fine particles of powder fine particles of paint okay or vapour in order that them systems don't
have um the gases penetrate through the conduit which they will on the seam welded type in order
to make a gas type installation use solid drawn we'll explain that a little bit more in my notes
and in the classroom so just remember two different types seam welded solid drawing
you're very very likely to be only using seam welded especially in a college environment
conduit lengths any of these here so stainless steel black enamel and zinc galvanized come in
a standard length bit controversial now over the times they've changed that standard length it
used to be that steel conduit was the exception to the rule a full length of steel conduit used
to be 3.75 meters old 12 foot actually as time has evolved electricians have said well we can't
get those in the tubes on top of our van they've actually reduced down the full length now to three
meters be careful the questions that i've got in the eFIXX apprentice hub there's about 1200
and there's about 600 in the installation theory section to help you with your exams
i still state in there that steel conduit comes in 3.75 meters until it becomes the absolute norm
it's a three meter length i'm going to leave that question as it is so just remember a full length
of steel conduit is probably now three meters when you get from electric wholesalers used to be 3.75
meters so we'll just name a couple of the other accessories we've got couplers okay we've got
couplers we've got uh female bushes okay and we've got lock rings i've got a male bush on the table
so i'll just see if i can find one of those so i've got a i've got a male bush okay so that's
a male bush and this is a female bush and we'll be using both of those in the exercises i've laid
out in the workshop in order to connect say to a coupler okay we'd have a box in here and we'd cut
time between the two we've got lock rings and lock nuts we've got different types of accessory so in
this case you can see we've got a black enamel and a galvanized box this is often called inside an
end box it's actually a terminal or a termination box is the proper term but of course we'll call
them end boxes they've got a pre-threaded spout so in other words the conduit itself would be
threaded like this one here conduit would be threaded and goes into the spout itself
and then would be tightened off so you'd wind it into here tighten that off okay in order to make
the connection in order to get into a coupler there's a thread in there as well okay so you
just wind it onto there make sure it goes on tight and then that would be connecting those together
conduit itself comes in different sizes the size being the actual diameter not the area the
diameter of the conduit itself the four common sizes so i find it difficult to say every time
i say it 16 is allegedly a common size so it's 16 this isn't this is 20 25 which this one is and 32
so you've got to remember the four common sizes of steel conduit are 16 millimeter 20 millimeter 25
millimeter and 32 we're talking about the diameter of the conduit i'll just throw the next one in
next one in is the bending radius and we'll talk about in the classrooms in my notes the bending
radius of this conduit is a multiplication of the diameter so the diameter in this case being 20
you have to multiply it by 2.5 that gives you 50 you'd set 50 into your compass draw yourself a
circle and that would give you the radius i've done a video on how to do bending radiuses of
twin and CPC steel armor mineral insulated etc uses exactly the same process but it's
the multiplication of the diameter of the conduit by 2.5 a couple of other boxes we've got the we've
got a tee box we've got a back entry or loop-in box and this is a four terminal one they obviously
do other ones with less holes so like a one terminal or one uh whole loop-in box and things
like angle boxes we'll go on on my notes to talk about things like tangent boxes and where we use
them etc this is just a whistle stop tour of um steel conduit i'll do the same on plastic conduit
to link to the notes i've got so let's have some key features to remember four common sizes 16 mil
20 mil 25 and 32 standard 3.75 maybe three length of conduit the fixings themselves coming this way
hospital distance spacer bar plane smooth surfaces for plane irregular brick work for spacer bar
damp surfaces for a distance hospital saddle for areas of high hygiene
the finishes themselves black enamel zinc galvanized stainless steel and shared eyes being
one of the others so that's a whistle stop tour of some of the stuff that we will do within the notes
that i've produced for Tresham college remember those notes can be
passed out feel free to contact eFIXX and look at the apprentice hub and maybe even nominate your
college for an e-fix uh visit from me and joe and we'll happily come down to your college and i can
pass on any information that your lecturers or the learners need so for this whistle
stop tour of conduit and in this case metal conduit i hope this video has been some help
you