so we'll back out on site today and with Graham Graham is GS electrical which I just think is
one letter away from sheer perfection on the side of his van but what am I here to
see today Graham live testing at the aboard and which tested my really interesting shown to the
wider public I'll see RCD testing of the board so we're actually gonna carry out a three lead
test on the RCD's in the board itself yes and what type of RCD's have we got in there RCBO's
so we've got a number of RCBO's in the board and we're gonna show you how quickly hopefully that
you can carry out the RCD test from actually within the board itself yes they see that in
this video presentation so Graham's gonna show the live test form within the consumer unit in
this video presentation but what you're gonna do first for me Graham so want to switch off the main
switch but before I do that I'm going to switch off each individual circuit the reason for doing
that is so that there's no power coming through the main switch when I'll do it when I did turn
it off with it with regards to these RCBO's I've got the RCD test but so I can already carry out a
functionality test on those by switching that the test button brilliant so by pressing the
test button on the RCBO's were actually starting the testing process already because this is part
of your functional testing and it means the main switch won't be on full load when your isolate is
that correct absolutely let's do that so then were once off and now I can turn off the main
switch fantastic so next thing we'll do we'll take you consumer unit cover off and we start those
tests moved to consumer unit cover and we're now ready to prove that we're actually isolated the
distribution board at the bottom of the double pole switch can you show me that please Graham
first of all we gonna test these voltage indicator prove it works does and I'm going to probe on at
the bottom of the double pole switch to prove that it is isolated so he's on neutral first
followed by line no volts comes off line off neutral we've gone on the earth bar neutral no
volts off the neutral off the earth bar and then finally I'm going to go onto the earth
bar onto the line conductor and no volts it's off the line and off the earth bar and then
finally he's gonna just recheck he's proving unit sorry the voltage indicator on his proving unit
to prove it works are you happy the bottom of that switches isolated the consumer unit
yes and now we're going to secure the isolation with a padlock and sign and replace the plastic
bar over the buzz bar next according to BS 7671 Graham what's the first live test we're going
to carry out supply polarity we are where we're going to carry out that test at the
top of the double pole which we are let's get ready and do that test for me please
okay we're showing you again rechecking our voltage indicator and we're going to test
first of all between neutral and line so he is on neutral first and then line and we show 230 volts
we come off line and off neutral we're now going to connect between the earth bar and neutral on
the earth and neutral and you find we get the beep noise because we've got a TN-C-S earthing
arrangement we come off the neutral in the earth but and then we're on the earth bar and line and
we should find 230 volts again have we got 230 volts again 230 volt and then we come off the line
and off the earth bar and what tests have we now completely Graham supply polarity we have offered
to missed in industry that's the first live test according to BS 7671 Graham has perform that test
he's now just going to show you that it's going to test his proving unit and voltage indicator again
so and you've got which indicator on the last part of the test so Graham is disconnected the 16 mil
earthing conductor in order that we can carry out the external earth fault loop impedance test we've
disconnected it Graham for what reason so the no parallel earth paths created by gas and water
bonding we have that the instrument is set to line and protective earth and we're on 2 lead hi
can you carry out on that test for me now please Graham so he has connect on the earthing conductor
first we're going to probe on to the top of the main switch on to the line conductor and we got
a reading of 0.22 ohms what's the maximum external earth fault loop impedance for a TN-C-S earthing
arrangement Graham 0.35 ohms so we accepting in the reading that we got that's fine so we're
happy with that reading we're ready for the next test so Graham's gonna now put the 16 mm earthing
conductor back into consumer unit what you're going to use in order to make sure you get it back
to manufacturers required requirements a torque screwdriver brilliant let's do that then Graham
okay so that's in and connected properly and we're ready to move on to the next test Graham
testing to carry out now for me PFC and we gonna test first of all between which conductors line
and neutral we can see say instrument up to test between line and neutral so we're
ready to go so on neutral first and then we'll get onto the line 2 lead highly test what was
our reading Graham 1.03 k amps okay and what's the next part of the test for prospective fault
current earth [ __ ] okay let's do that next and sees changes instrument now to line and
protective earth so it's gone on the earth bar first and then the line conductor again 2 lead
hi and this time what reading we get Graham 995 amps of the two reading get which one
new record the highest and that was the one that we tested first thank you Graham so if
those two readings we've just taken Graham the highest one was just a little over a thousand
amps what's the braking capacity of the incoming supply Authority's fuse at this installation 33
kilo amps and what's the braking capacity of the devices in circuit you're our RCBO's six
kilo amps so therefore you happy with the fact that just a little over a thousand amps can be
cleared by those devices yes okay so Graham is gonna shows how to perform the RCD test within
the consumer unit itself we have the main switch now in the on position and only the circuit under
test in this case which circuit we're gonna do the RCD test on first Graham the cooker we are
going to do it on the cooker circuit so rather than going to the circuit taking off the plate
and doing a three lead test there Graham's gonna perform the RCD test on the auto set
to 30 milliamps actually within the consumer unit itself let's see that test goes on neutral first
and then line I'll help him pressing the test button it will run through the sequence now
so that's the test completed and see how quickly it was done we now scroll back
through the results the first one is at half times where nothing happened so in other words
we passed 15 milliamps or 30 milliamp RCD and nothing happened we did it at one times at zero
degrees we've got 8.88 milliseconds and then at 180 one times you were 18.5 which of those would
record Graham the highest what's the maximum milliseconds disconnection time it can be 300
and were well within that we now go to five times at zero degrees you got 8.38 milliseconds and 18.2
milliseconds at 180 degrees of the two reading which do we record highest what's the maximum
for five times forty forty what 40 ms it is yes forty milliseconds and we would record them we're
now going to go and show you again on another circuit perhaps we'll choose a light in circuit
and show you how quickly you can achieve all the RCD test results in this case for RCBO's within
the consumer unit itself so we've worked our way down off-camera and now we're at the lighting
circuit at the ends and we'll show you how quickly you can do the same test on the lighting circuit
saves you go into the lighting fitting unscrewing or taking down the fitting in order to connect
your three leads and do your RCD test so let's do the lighting circuit for me Graham so neutral
first again gone on to the line I'll help him out just for speed by pressing his test button
and we can see how quickly we've carried out the RCD test on a lighting circuit from within the
consumer unit itself we can scroll through pick up the results record him in our test paperwork and
that's it for the test within the consumer unit itself Grahams now got a choice after carrying
out a measured external fault loop impedance if he wants to add that to his measured R1 plus R2
readings done dead in order to calculate circuits total fault loop impedance in other words the Zs
of the circuits or whether he wants to make a decision to measure some of those so we've
shown how quickly you can carry out an RCD test within the consumer unit and especially where
there's RCBO's and especially where you've got to carry out that test many times thank you Graham so
Graham this is lovely to see so I can see you've put on some stickers on the exterior of the
consumer unit on completing all your testing you just explain to me what you've actually put on the
outside of this consumer unit for us here we have the decals that indicates to two different colour
wiring systems the durable sticker for testing RCD test button sticker and dates of installation and
next inspection next inspection maximum gap is how many years 10 years it's lovely to see that you've
actually left a sticker there with all the test results on the exterior of the consumer unit or
something often missed in industry and it's lovely to see you done that Graham thank you very much
well I think that one fantastic do well I'd like to thank you Graham for that how do you think it
went yeah really good the RCD tested at the board saves time massively obviously not having to go
out into the installation and take covers off to do the tests there and that's no tweak for
me because I might be old school that all would have been going out 3 lead testing at lighting
point of the cooker etc and Graham said come along and watch me do it mate know I'll do them from the
board which is yeah just adds another string to everyone's bow so when we're out there in industry
we can carry out the RCD test inside the consumer unit along with we did the external earth fault
loop impedance prospective fault current tests we proved an isolation yeah polarity supply so
all those test carried out in the board saves us huge amount of time and then we said whether we
add together the Ze to our R1 plus R2 in order to get it said Zs you agree with that yeah so we've
got a choice in I'm we were the one who did that we'll go and measure him but I think the RCD part
of that video saves everybody in industry a lot of time thanks a lot Graham for that and we get this
moment now then when we get to do that well we hope this video has been some help well we almost