in this video presentation we're going to look at the switch fuse connection unit
often called on-site a switch fuse spur and we're going to look at it from the point of
view of the back of the electrical accessory and we're going to be looking at identifying
the final circuit terminations as well as the load terminations now these change between manufacturer
i've got three different manufacturers here and we will see in this video presentation how
the position of the terminals in the back of the accessory and the labeling of them differ
between each of the manufacturers so a switch fuse connection unit allows us to take a final circuit
and fuse it down appropriately to the load that we're feeding the section here on this one is
the position of which the fuse is inserted and they are BS1362 fuses ones we've seen previously
for plug tops remembering the three common sizes of 13 5 and 3 amps all of them come fitted with
a 13 amp BS1362 fuse and in the workshop it's our responsibility to change that fuse
appropriate to the load in which we're feeding the fuse connection unit here incorporates a switch
this is a double pole switch and can be used for isolation we often see these out in industry
feeding things such as electric hand dryers and in domestic dwellings perhaps in kitchens
feeding things such as washing machines dishwashers and fridge freezers maybe even
identified with writing on them in order that we know that that switch fuse spur or switch fuse
connection unit is actually the isolating point say for an extractor fan so let's bring the camera
in and look at the positions and the labeling of the terminations on the back of these three
switch fuse connection units next so this is the first of the three switch fuse connection units
we're going to look at the back of and this is possibly the most simplistic of the three
one side we can clearly see the word supply the symbol for earth an N for neutral and a L for line
on the second side we can see the word load we can see an N for neutral and a L for line and this
symbol for earth so let's look at the side first of all labeled supply this is our final circuit
wiring it may be that we've wired our circuits in PVC PVC twin and CPC cables sometimes called
twin and earth cables it may be that we wired our circuit in PVC singles so it's a circuit from our
consumer unit that goes around to our electrical accessories it's the supply side we can see the
symbol for earth where our CPC will be connected we've got the N where our neutral conductor or
conductors will be connected and the L where our line conductor or conductors will be connected
so let's have a look at the load side of this switch fuse connection unit so we've got our
terminations neutral line and where our CPC will be connected and this will be the item of which
we're installing such as the hand dryer it could be that we're using fixed wiring so again that
cable may be still buried in the fabric of the building or incorporated in another enclosure
or it could be that we're using the cord grip section at the bottom and we're coming out with
a flex or flexible cable in order to connect to our load it's now important that we look at the
load and match the fuse installed within the fuse connection unit to match that remembering
they always come with a 13 amp fuse and often this will need to be changed maybe to a five or a three
amp fuse depending on the load so let's have a look at our second fuse connection unit next
so this is the back of the second switch fuse connection unit and already you can see the
layout is completely different we have one word that we recognize from before which is load
we have a new word introduced which is the word in we still have N and L to represent neutral
and line conductors and on the right hand side we have two brass terminals and the
earth symbol where our CPCs will be connected so we're now looking for our fixed wiring terminals
we've got at the top an L identified above it with in and at the bottom an N identified with the word
in as well this is the circuit wiring this is the wiring from the consumer unit that we've installed
to feed this electrical accessory the CPC is from our final circuit can go in either of the
brass terminals identified with the earth symbol it wouldn't matter which one we chose of the two
in order to install our final circuit CPC the item we are feeding from this switch fuse connection
unit again the example being that electric hand dryer will come out of the terminals labeled with
the word load so as we look at this we can see an N with the word above it saying load that would
be the outgoing neutral and on the other side we can see the word load with an L being the outgoing
line conductor remember this could be in fixed wiring or again it could be in a flexible cable
and you can see at the bottom there we've got another cord grip to support that flexible cable
if it went outside to the electric hand dryer and again it wouldn't matter which one of the two
brass terminals identified with the earth symbol we use for the load CPC again before finishing off
this electrical accessory please ensure the fuse on the front plate has been appropriately selected
to match the load so we can see on the back of our third switch fuse connection unit we have
yet another layout for our terminals however we do have words now that we recognize we have the word
in and the word out so our final circuit wiring will be our in terminations so we can see there
L in for a final circuit warren and N in for our final circuit wiring in our line and neutral
terminations we can also see that we've got two brass earth terminals one on each side
of which our final circuit CPC can be connected and again it wouldn't matter which one of the two
you choose to connect your CPC into hopefully now it's quite obvious which term i was going
to use say for that electric hand dryer our load element of the actual circuit itself
so we can clearly see there an L marked with the word out that would be our line outgoing
and N out is our neutral outgoing to say that electric hand dryer again it wouldn't matter which
of the two brass terminals we chose to connect our CPC into and again we've got the ability
if we wanted to use a flexible cable in order to feed our load we've also got a cord grip as well
so that was a little look at three manufacturers and we can see clearly how the termination
positions and the labeling of those terminations differs between each of the electrical accessories
i hope this video has been some help