now back when i was a lad before we had the face tube and the you-book we had to be entertained
by simpler pleasures one of which was a puzzle called spot the difference where you'd have two
separate images that looked very similar but had some small alterations to them let's recreate
the magic of those times by trying to find the differences between these two consumer units from
Lewden now as you can see they're the same on the front and they're the same on the sides but what's
this on the top here we've got different shape knockouts and on the back of here there's also a
quirky little grommet as you can see in this still image now there's one more difference as well but
that's hiding under the lid here so stay tuned to the end of the video to see what that is along
with some hidden gems from the second amendment to the 18th edition of bs7671 but what's going on
with these round knockouts for a long time luden have been advocates of the square knockout so
why the change and are these round holes going to be round our way permanently well the good
news is that both variants of consumer units from luden are going to be available side by side so
you can pick whichever type you prefer which is great because actually they both have advantages
and proper applications let's start with the classic square knockout what's the benefit here
well obviously it's ideal if you're running cables in trunking the big knockout there is
40mm by 40mm so if you're running 50x50 trunking down the wall that's pretty much spot on and the
smaller knockout to the left there is about 32 mil by 18 mil so perhaps a 40 by 25 mil trunking
would be suitable for that one now if you're not using trunking but you still want to bring your
cables through the top or the bottom of the board then you can use luden's rectangular grommets
with their unique piercing skin to maintain ip ratings when you bring the cables through there
another advantage to using the square holes is that it actually gives you a much larger area
for bringing cables through than a round hole of the same diameter wood so this 40 by 40 mil hole
will give you a hole of 1600 square millimeters whereas a round hole of the same diameter would
only be 1256 square mil so it's a more efficient use of the space there so if square knockouts are
so good why have luden included round ones as well as square ones and only round ones on this board
well it's so you have options and flexibility for example sticking with our original board here the
32 mm diameter round holes have been strategically placed to make it easy to bring tails through to
the main switch no matter which face of the board you bring them through looking at the board with
only round holes now there's still some very clever thought gone into these that you may not be
aware of so for example we've still got the 32 mm options for bringing tails through on all faces
but there's additional options top and bottom for final circuit entry at the end of the row
of knockouts there's a 25 mm diameter hole for larger cables but then between the 32 mm and the
25 hole there's a row of 20mm diameter holes for smaller cables to gain access which is all good
however what about if you want to bring several larger cables through there and the 20mm diameter
holes simply aren't big enough of course you can always drill them out to be larger with a hole saw
or a cone cutter but even with this simple process luden have put some thought into this by carefully
spacing the holes to allow them all to be opened up to 25 mm without compromising each other
little touches that could make all the difference to your installation and they've done so well you
probably wouldn't even be aware of them of course having the option to have all round holes has its
advantages as well because it means you can bring cables through grommets glands conduit or steel
wire armored so by creating the two variants of consumer unit it means you can pick the correct
type of knockout for the individual installation that you're putting it into now just when you
thought we were done with knockouts we're going to look at the back of the unit and here we've got
the option to knock out a rectangular blank and install this special grommet that fills that in
which then gives us further options for removing the plastic blanks so we can have half the blank
open for cable access on the left or the right or we can take the whole thing out if we've got lots
of cables coming in at the back and that plastic grommet prevents the sheath of the cable from
getting damaged where it passes through the metal work now i promised you at the start of the video
that there was a surprise hiding under the lids of the unit and it's now time to have a look at
that so if we look closely you can see here that we've got pretty much all the protective devices
in one unit and it's actually quite a nice representation of some of the changes that we've
seen in the second amendment to the 18th edition of BS7671 you can see here we've got an mcb
protecting the surge protection device so there's no more risk assessment needed for that under the
second amendment and hopefully we'll be seeing a lot less resistance to that being installed now
there's certain places that it must be installed and away from these the only reason it wouldn't
be installed is if the owner of an installation declares that it is not required due to any loss
or damage being tolerable and they accept the risk of damage to equipment and any consequential loss
then we've got an rcbo and looking very closely at that you'll see it's a type a rcbo which makes
sense as under the new amendment type ac rcds can only be used to serve fixed equipment where
it's known that the load current contains no dc components so that's you know basically nowhere
and then finally it's Lewden's new afdd all ready for use in compliance with the second amendment
the 18th edition of bs7671 in the relevant places we're on the verge of releasing a free training
package on affd's in the second amendment to help you with your cpd so please keep an eye on the
know-how page of efixx.co.uk for that or the luden academy page on luden.com depending on when you're
watching this there may even be a link in the description below but at this point it's worth
noting that luden's afds have been independently laboratory tested and certified by intertech and
bears the european safety s mark the s mark is a voluntary certification scheme demonstrating
that the product continually meets all relevant technical safety requirements verified by regular
inspections of the manufacturing facility by Intertek so that's some added reassurance that
you're getting the top quality products that we've come to expect from Lewden so there we go that's
a quick overview of some of the changes to these consumer units from Lewden but as always we want to
hear from you which type of knockout do you prefer and why are you looking forward to installing affds
what do you think to the second amendment in general whatever your thoughts or questions
please leave those in the comments section below and as always thank you very much for watching