that caused this connector to fail okay and the consequence of being sorry it was in the
loft sorry did you say i thought you said burn the house down the house down it set fire to the roof
as you clicked on this video no you haven't already seen it i've got the same people in
front of me and off camera i've had some great discussions that i think are worth sharing with
you the previous video the conclusion was the physics of a conductor whether it be connected
over tight or under tight has a massive bearing on what happens to that conductor throughout the
life of the installation it is within and if you haven't seen that video i'll leave your
eye above my head or in the description below the link that takes you there and i recommend
you watch that one first however we've got loads of other questions that we want to add in on talk
i'm going to start with you ian the screw heads whether they be on an rcbo the main switch the
neutral or earth bar are often different sizes and different torque settings why that stems from
manufacturing standards so you'll find within a number of product standards for for different
products whether it be switches whether it be circuit protection whether it be plugs or sockets
you'll find similar information in a lot of those standards pertaining to the mechanical withstand
strength of screws and screwed connections based upon the metric size of those screws so when you
say sorry so if i've gone from a lewd and consumer unit into a different branded one and i'm looking
at a very similar device and all of a sudden the screw head is larger or smaller than yours that's
going to affect the torque setting possibly of that device meaning that i can't look at an rcbo
from all the manufacturers and get exactly the same torque setting quite potentially um
products certainly circuit protection products um they're designed as individual components firstly
and designed to accept conductors of different sizes so hence larger conductors generally need
larger terminations hence larger screws okay and larger screws bring with them higher torque values
and we see that don't we from the the neutral earth bar rcbo and then the main switch the main
switch often as a rule has a larger torque setting and taking larger conductors that makes sense
now this isn't covered is it in bs7601 if i missed the page out in there about this none
of this information is covered in bs767 it isn't it's all about product standards okay and it links
into when we talked in our previous video about the potential to have fires but for me the other
question that keeps coming out is i've connected inside a consumer unit i've gone to the top of the
six amp circuit breaker i've done it's a required torque setting and one meter away from it i've run
into a ceiling rose and pendant or maybe i've taken a feed to the switch and i've done that
termination up correctly does that need to get the required torque set enjoyed should be simple
right it's just just moving the problem from one place to another i've moved it a meter yeah okay
but there's no torque settings on the back of my light switch or socket is that not that i'm
aware of no not that i'm aware of either is this something steve that you think should come into
practice definitely that we should start setting those 100 yes okay from your experience ian with
product standards is that something you could see coming in in the future quite potentially yes okay
now when we go to our forensic expert and i like to say that in the other video as well
whenever i could get forensic in okay so rob our forensic expert we talked about fires possibly
cause more at the mains end of an installation in your experience of investigating these have
we seen that fire problem maybe appear in the back of a cooker switch shower switch socket outlet etc
yeah yeah it can occur anywhere i mean the most common place is a highly loaded
part of the system so typically intake to the building or somewhere like that
um but the issue occurs when a conduct what a connector is undersized and it can't dissipate
the heat that's generated by the resistance of the connection so for example i've seen a
failure someone extended a shower circuit using a small undersized chocolate block
connector okay um and it was fine for years until his son had a party and all his mates
the following morning had showers i'm glad you said that okay because i envisaged the party at
the shower running on throughout the bay steve's already in there old hair's gone back he's in okay
so in the morning yeah in the morning there was a prolonged use of the shower one person after the
other right and that caused this connector to fail okay and the consequence of being
so so that's probably so that's some party to start well let's go there first i mean
replacing the lounge carpet for a bit of spill alcoholic beverage maybe you know a cost that
you could incur rebuilding the property that you once owned it was a little bit difficult
task was anyone injured in that no no no no never got out so that was a screwed connector
so that takes us back to maybe you know any of the other instances obviously it's a poorly designed
circuit which i'm sure you would have jumped in on there because we've extended it into a chalk
block but that is an issue and it's an issue that's easily solved especially on on i'd say
on the continent screws in the back of electrical accessories are a rarity to see
yet we still screw in those locations is the solution to remove the screw
well i think with with historically we've got away with it because a lot of screw connections have
been oversized or fairly chunky bits of brass that have been able to absorb any heat or to dissipate
the heat without deteriorating in service okay so i'll jump in there before you go on inside
i'm thinking you're saying that we've tried to keep maybe things at the same cost and to keep
things at the same cost maybe we've used less of the earth's resources in order to make them
and maybe now we're nearer the the limits of where it is for an ampere rating
possibly it comes down to economics but uh i don't want to be drawn on that technically there tends
to be less material in modern connections okay and that is a factor when we talked earlier about
how tight those connections can be i think older connections had a larger sweet spot of
of acceptable torque whereas modern ones perhaps you've got to get that torque closer to the to the
mark and keep it there for the for the duration and that might not be so easy to achieve also
i think we have less of a problem in the installation because those circuits
the back of a socket back of a light switch tends to be less high current okay and you can get away
with it until perhaps you're putting those devices under full load and then they might not be able to
cope with it okay so again maybe a little bit on hopefully this won't happen the granny cable for
the ev charger goes through the window that socket out there that's only ever powered the tele and
a table lamp is now going to spend a few hours powering the charging mechanism within your car
we might see this problem it's always we always seem to chase the same issue center change
the same problem around the installation so we could have that after we've had the shower one
shied regulations don't tend to ever look at anything like this do they they never sort of
give us any guidance on making those terminations of a certain variety however we have seen recently
haven't we the levered style connectors yeah okay from a personal point of view good idea bad idea
i think it's a it's a relatively good idea i've not used it myself i've not had a chance to
play around with them which i'd like to give you a a proper opinion yeah um but the the
principle of it seems seemed fine yeah and i think the levered connectors say in a box
located close to a light fin noise we trust it don't we we trust that levered mechanism
but it's removed steve i've done you have a job here because that levered connection
going back to where we started has removed the need to have it at a certain torque
setting yes so is there a common ground or is it a move to levers what would you say
from your experience rob that you would suggest that lever should be in place or would we say
screws or a combination of both torque settings what are you going to go with if you start talking
about these maintenance three connectors yes they tend to as far as i understand it contain
levered connections or some sort of spring-loaded mechanism that maintains contact pressure yes
from that perspective it's a very good thing some of those connectors i think don't have a
big bulk of of metal so if you start loading them let's say beyond their rating then there
might be issues but that's going to be true of all connectors okay um but it yeah it gets away with
avoids some of the problems that are associated with screw connectors
leave the connectors good idea do you think ian i think on some products okay i'm glad you said
that because i'm going to flip it straight back out and you knew that was going to come probably
so if they're a good idea why can't i have a neutral bar earth bar of actual levered connectors
it removes the need for the torque screwdriver which we discussed and we said it was very
important especially in your experience rob of the electrical fires being a forensic investigator
okay so why are we not putting those levered uh connectors saying consuming units because
it's something i've seen on the continent another one of my favorite phrases well certain
parts i mean first of all there's a cost element and a more complex design element to
applying it across a consumer unit for example and certainly some of the individual devices within
um and some of those devices are carrying quite large currents which are generally beyond
the capacity of those type of terminals okay but when you think we always think there's always an
opportunity to improve stuff so we change from maybe the petrol or diesel vehicle now we're
going towards a battery one we haven't redesigned that car they all look the same okay there was a
golden opportunity to redo that however as we move towards a world that may or may not have our fault
protection in it that might have been a really golden opportunity actually to have a connector
on there that that didn't require any talk sense i know you're still gutted i want to have a
okay and again we're not at the point where we know under amendment to how many more times
they're going to be introduced if at all but is that something that we should be embracing
new technology choida and moving forward and actually trying to make life easier for everyone
totally agree yeah yeah totally agree we should be moving to ease ease of installation ease of use
across across across all sorts of examples yeah and we saw that before didn't we in our our first
video we did we talked about rcd and testing rcds you came out with a simple solution because we
trust our manufacturers and we brought up trusted manufacturers previously the manufacturers of our
talk screwdriver in a previous video and the manufacturer of our consumer units
but it doesn't really answer the question does it we do we need to be talking up these screws do
you know i mean it's just talking screws isn't it true to say with that type of connector as well
they're designed specifically for a particular conductor size in mind
they go for size but they go for classes as well they do one class one class two class five
okay so they're covered from that and they make different size physical sizes for them
so the only barrier may be to wider use of a levered connection which we believe
will offer would we say tension or pressure what would you say contact pressure yeah the force
applied to the conductor over the over the time and that's where the torque screwdriver came into
its own in our previous video because we got it at the right torque pressure and therefore
we were worried about the the physics of that conductor obviously we're moving we're moving
within the answer isn't we we know the answer we're just slow to move towards you are we
yeah i mean historically i don't think there's been that many problems with the old
screw terminals i agree um but as you say if you start increasing the loading on the system then
you might see more of that and when you do get failures into the system if someone's lights don't
work or if the socket doesn't work tends not to be the end of the world they don't always result in
fires so probably haven't got as much uh industry interest as consumer units have historically yeah
and i totally agree that i like a screw connection as much as i like a levered connection something
quite satisfying about making off conductors into into outlets and then obviously pushing them back
into place i'd always recommend you obviously we recheck titan once you've moved them we we
suggested movement in our previous video caused an issue when we were talking about torque well
the same thing there is it's that movement of conductors and preventing movement of conductors
which is a benefit to us so as we circle into this then so we're suggesting the screw connectors here
and you're from a forensic point of view not too worried about a screwed connection
some screw connectors have failed i mean i've seen ceiling rows connectors uh
cause cause fires are right in roofs um it happens you know it's
to get a fire um and to get a sustained fire it tends to be an inline resistance that you get so
it's it's not a fault between conductors it's carrying the current that causes the heating
and for that to lead to a fire you've got to be very unlucky you've got to get certain
series of events to occur and it all has to line up and dissipate energy for a prolonged
period of time it doesn't always happen it might just be that the lights stopped working
yes but if the lights are flickering for a prolonged period or something like that
then that can lead to to these these events okay and in both ways that would have been
solved by either having a torque setting on the ceiling roads and a screwdriver that did it up
or a levered connection because then we've got that reliable electrical connection agreed yep
bs7671 doesn't doesn't suggest that we can go one way or another okay so we're they're
not suggesting we do screws or we do levers or anything like that so where would the wiring
regulations you know help us point us in would it be through our workmanship through correctly
following manufacturer's instructions that we talked to him about before sure yeah all the same
same stuff applies um there's different types of connectors that are acceptable and there's
there's regulations um that stipulate that i can't remember them off the top of my head which
is really bad um so so yeah again it comes down to good workmanship um good use of um proper products
and uh taking account the manufacturer's instructions and i think that's where we concluded
our previous video didn't we i started out on our previous one actually saying you're all in cahoots
if you haven't checked out the video again it's all above my head and in the description but it
goes back to it so conscientious installation however you do it with the correct materials
to manufacturers instructions where the example of the uh the chuck block yes on the shower that
that doesn't obviously it contravenes the the the fundamental principle of seven six seven
one it does and good workmanship up until the point of the connector block that circuit was
correct wasn't it it was the point of which whoever took on the engineering judgment from
that point forward caused the point of failure that's right was it was it in an enclosure or
was it just a bit of blood that was hanging up in the yeah in the roof space and i'd like to suggest
that isn't the electrician okay i'd like to defend anyone who's currently diving in with the comments
because we are all of the things that we suggested so we will be installing them as required and
by bs7671 using the correct tools and equipment and as we said in our previous video rob that puts
you out of work doesn't it i've got a feeling at the end of this series of videos that we're
going to have with you and rob that we're going to have to have a bit of a whip around don't we
yes okay i got any other examples of fires for us that you want to say because i did like that one
the one in the previous one where you obviously described the jelly baby okay have you got any
other ones that you think would be poignant to our audience especially in that electrical sector
um well like we said in that video it's quite common to find fires around the meter position
it's not necessarily the meter you know there's lots of equipment there and it's about finding
what what bit has failed but it's not just fires we've also seen failed neutral connections on
three-phase installations that can cause very strange volts beyond that point which can cause
fires or failures to equipment beyond that point so a forward connection is not just a fire hazard
but it could lead to some other other issues yeah and it's all about taking it seriously isn't it
as we we probably joked around a little bit in both videos but it's that you know conscientious
installation correctly will not cause a problem with it and it will not cause a problem that
necessarily falls at the electrician's foot feet you know it's not their problem so if you
do your job correctly it moves it across to the manufacturer and we trust a manufacturer right
so as long as the manufacturer is doing their part to ensure that the products they produce are under
a constant checking process yeah to ensure continued quality yes i mean you've got an initial
testing and verification and for example here the application of a talk setting is a the result of a
lot of testing to find a particular sweet spot on which the device is happy the conductors are happy
um and it's then translating that information into the installation and and keeping some uniformity
and limiting risk yeah i totally agree and you know this is the example of that you know we've
seen them online people order from an online retailer that offers next day delivering a
charging unit for their mobile phone and they charge it in and walk away from it it's not a
huge load but it's on maybe for several hours and maybe that perishes and causes a problem that's
goes back to what we just said there if you had a trusted manufacturer you went maybe to the store
you bought the phone or we don't expect those things to fail do we we expect everything to go
through that cycle and being electrically safe and installed correctly which again means rob
you're out of the jobs okay so hopefully this series on talk has been one that's been helpful
and we've covered lots of different things and if you haven't checked out that playlist
also i'll leave a link for that in the description i'll recommend you do that also we've got a talk
cpd so you can take your level of knowledge up and be certificated and also that will be left
in the description as well as you care on this journey but as always we're interested in your
comments and your feedback and if you leave them below i'll attempt to get back to as many as i can