exciting times for me for a number of reasons i managed to stand on the left-hand side where
joe robinson would normally be standing and i'm standing today with marcus marcus has joined us
he's new member of staff and what we're going to look at today marcus so we're going to have a look
at spds and how they might be installed remote to a consumer's unit in let's say a domestic dwelling
do we need marcus an spd in a domestic dwelling again it all goes down to warrant in the
installation costs and the equipment costs whether the need for an spd is required so and what we're
seeing is the 18th edition unfolds is that actually manufacturers are starting to inbuilt
the spd within the consumers unit we saw some at the electrode from Hager yeah that was really nice
we really really like them however once we start putting this type 2 spd remote from the consumers
unit there's some issue with the length of conductors yeah so the regulations state that the
length of the conductor should be less than 0.5 of a meter however it's one of them where it also
says but it can be up to a meter long as well so we've got to keep it at half a meter but we can be
a meter yeah that sounds easier than it is when you start looking at the length we put that really
close when you start looking at the length of these conductors you can see how quickly you can
go beyond half a meter yeah definitely so we can see how we're justifying actually fitting the spd
within the consumers unit itself yeah so what we can do is we're gonna bring joe in and we're gonna
bring the camera in as well we're gonna have a little discussion look at the lengths of these
conductors and how we've actually fitted it as well okay then joe so we've brought the camera
in and we're just gonna look at the general layout of what we've done within the consumers unit and
actually the spd itself what size breaker did we select this time around so we've put in a 16
amp breaker we've received various different bits of advice from different surge protection device
companies and we're looking at between 16 and 32 for a domestic dwelling of course always check the
manufacturer's recommendation on this because it may vary quite significantly
from installation to installation and also from manufacturer to manufacturer so by selecting a
16 amp circuit breaker here it automatically meant the cable size must be a minimum of
2.5 mm it is yeah 2.5 millimeter squared for our conductors here so for instance we chose and say
a 32 amp we might have been using four or six mil absolutely the crucial bit is the actual returning
protective earth conductor yeah which has to be what size joe that has to be at least a six mil
it does a six millimeter squared cable we said that we want to have half a meter of cable to a
maximum of a meter is that true yeah and this is where this gets quite interesting actually
because there's a number of issues that are raised now when you look at the proximity of this board
to this board it looks really close you're looking at that and thinking that's got to be within half
a meter surely but actually when you start to follow the path that the conductors take
and that's what that measurement relates to we can see that that starts to build up
so what we've done here gary what how have we installed this what sort of craftsmanship
have we worked towards as we always do one of my students fitted this and of course they've gone
for let's dress the cables best we can so our protective earth conductor's come down it sits
along the back rail it comes up here it comes along and then it's hidden and then obviously
that's probably out for me already it's it's getting on for that yeah so the the ladder
has installed it and fair play to him he's thought i'll do a really nice neat job i'll
impress my lecturers by doing this really well this was a bit of an extension activity for him
and by doing a really really good neat job he's actually potentially violated quite an important
regulation which it's quite an interesting sort of point for debate that isn't it the fact that you
know it's got a it's got to look good yes but it's also got to function in the way that you know as
prescribed because if it doesn't then it can be as neat as you like but if it doesn't do the job then
we're looking at a bit of trouble there aren't we so let's let's just measure this guys and see
see how long we've actually got i mean we'll just take a rough measurement here that's coming round
and up and then it's coming back across this way and then it's coming up and into the top and we've
actually got to a meter already just with the earth conductor and bear in mind that the distance
when we say that 0.5 of a meter or one meter that distance includes the line conductor getting
the line coming so the line conductor comes it comes along yeah we've come round we've come up
and we've gone all up and down like we would to address it neatly to give ourselves a little bit
extra yeah it's probably another half a meter there get them on for i reckon somewhere between
one and a half and two meters uh is that path at the moment which according to the regulations is
not acceptable so it looks super close preferably these are going to be fitted inside the board the
reason we didn't we could have clipped it onto the actual rail here is you lost two of the seven ways
so that wasn't good practice so we've fitted it remotely thought we're doing a great job and we
can instantly see we've gone over the half a meter to a meter rule that we've got to keep with him
absolutely so it's just something that we just need to keep in mind isn't it something
we need to look out for when we're doing installation of surge protection devices
so i think what we're going to do now is we're going to redress the consumers unit
and the spd and see if we can get it down closer to that half a meter rule let's do it
so this consumer's unit and spd enclosure was connected up by one of our learners and he's used
nice long loops and dressed it as we would normally dress cables in the consumer's unit
what does bs7671 say about this marcus well as you can see gas and regulation 534.4.8 concerning the
connection of spds it talks about the connections relevant to an spd and maybe an overcurrent
protected device they should be kept as short and straight as possible and also all cable loops
should be avoided if they are unnecessary so with that in mind can you re-terminate this consumer's
unit making those cables as short as possible for me marcus yeah i'd be happy to do that i guess
so i've reterminated the conductors in the consumers unit in spdj and we're right to
measure it to see if we're below the 0.5 or one meter values absolutely let's have a look so we've
come out the top of the mcb now bear in mind we need the combined length of the line and the earth
conductor for this so we're coming up here and across so that's just around 300 ml by the time
we've come up and across and then we've got that all-important return path as well with the earth
conductor which is coming down here uh so again by the time that sort of looped round being a little
bit over generous there now the return path on the earth is around the 500 mil mark but it is the
combined value of the earth conductor and the line conductor that matters so we're looking somewhere
above 0.8 below 0.9 meters here so we're over the 0.5 value we're below the one meter value so where
do we stand in connection with the regs marcus so if the value is greater than the preferred
0.5 meters then there's a couple of options you can choose from one being you can select an
spd with a lower voltage protection level there's different installation methods and also installing
second or third coordinated spd's in line with that one so do you think it's fair to say marcus
that with this current method of installation we haven't quite complied with the regulations
without getting a lot of further information about the spd that we fitted and various other things
what do you think might be a smart solution moving forward definitely and i think that's
why a lot of manufacturers have come forward with the idea of incorporating the spd's in their board
it just gets rid of this problem and stops the electrician from having to decide whether to
incorporate new spd's and not absolutely so for the sake of perhaps slightly more ways on the
board installing a bigger board and fitting the spd inside that consumer unit that's probably
going to be the way forward as far as we as a college our recommendation is concerned so what
we'll do now will actually be as good as our word we're going to move this surge protection device
from this remote unit we're going to put it into our consumer unit and then we'll talk about the
torque settings that we need to crank that up to yes i've stepped in and i've now moved the
spd within the consumers units cost us two ways in the consume unit itself and now we've got a line
conductor it takes a very short journey down is connected here and our protective earth conductor
goes straight into the top would you suggest that's under half a meter joe that's definitely
looking under half a meter now we could measure that up but i'm confident we've got that down to
the value we need it to be so next up is to return the terminations to the required torque setting
which i think in previous videos has always been your bag absolutely so this is exciting so uh
currently uh my torx screwdriver probably can't see it in a little window there let's see if we
can get that in shot uh we're between 2.4 there and 2.6 now that is uh normally around the 2.5
mark on a consuming so what we're going up to here guys we're going to try for the world record 4.5
newton meters of torque joseph can i ask you to double check that value for me there gary i'll
have another look uh yep 4.5 so i think it's time to warm up those arms and wrists because
we're going to try and see if we can get up to 4.5 newton meters now i think it's quite
important that we prove that we are actually doing this to the right value so here we're on 2.6 2.8
okay 3.0 now this is such a high torque setting it actually gets quite difficult just to turn
the torque setting device to the right value so there's 4.4 there's 4.6 so we're going to go
just midway between those two that's now on 4.5 newton meters and that was stiff
just setting the torque screwdriver to the right value we only want to see you do it
joe we don't need you here you're bleeding on about it let's get set up and ready to go
let's do it okay so joe's been limbering up off camera and this is live to the camera let's
see if we can get it up to 4.5 newton meters of torque before joseph rips his wrist off here we go
god breathe this is genuinely difficult right i'm worried about snap off the buzzer all right
here we go 4.5 oh cool there it goes my goodness right okay so let's uh all the
terminals we believe absolutely the instructions are not very clear i think everybody's going to
want that with these people even harder because it's not stranded on the bottom
oh no i don't think that was a click i think that was it was it was a screwdriver a head slipping oh
no i don't think i have i'm gonna i'm gonna have to get down to this one's quite low hang on let's
try it there we go that was definitely it there we go right and on this line conductor as well
oh my goodness that is really difficult there we go 4.5 newton meters wow ain't coming out
of there in a hurry as you can tell we're still working on the balance of trying to
get three people in shot we're microphoned up and massaging people's egos so we'll
get the same amount of time we're sure to be contracts coming out soon in the sets
if i don't get 33 to 30 of the time on camera i won't be shooting them will not stand on the right
right so let's conclude it and when we got to then so we've found some issues do you agree
with that marcus yeah definitely yeah joe the issue with the length was yeah really
eye-opening actually because we genuinely not checked that before we made that installation
and so we've actually learned something in the course of making this video i've also learned
that the torque settings are massive i mean at 4.5 we have to keep checking that paperwork yeah
okay there's there's loads more things we want to do with this spd we'll leave it in circuit
we've got insulation resistance testing to look at and the effect the spd will have on that
um we've also got whether the windows are indicating whether it's in good working
order or whether it needs to be replaced and how easy are these cartridges to replace
yeah and maybe some more information on the difference between stub wiring and v wiring
which is something that we've just literally started to scratch the surface yeah there will be