well gordon you've brought me down to this Contactum and three-phase
distribution board and you said we're going to talk about surge today
yeah a lot of people investing now in surge protection for that sensitive
equipment you might have in a factory or warehouse environment
but how many people actually check to see if those surge protection devices
are functioning as intended? so what are you suggesting
that we're not going to the surge device and looking to see if we see a green or
red window well i'm suggesting yeah people don't look behind this hidden
door beyond this lovely mechanism and peer through the window and notice
if that flag has turned from green to red okay so what's the solution then
if we're not visually looking at these surge arresters well we're going to find
out how to make an indicator device that sits alongside the
panel to show you the status of the surge protection device so you're
telling me this green lamp here is equally indicating the fact that it's
in a green status there yes exactly correct and if the surge
arrested life had gone and that window in there had turned to red
you're telling me this is going to turn to red well i'm hoping so
should we take you to the bench let's have a look so can you talk me through
the processing okay so on a lot of surge protection
devices on the back you'll see these three connections there so these are
volt free contacts so there's no power derived from the wires coming in from
the circuit but you can use those normally open
normally closed to trigger a device if the surge
protection device has failed so normally you'd see the flag change
from green to red you would do or if someone's removed the device
itself you'll see there's a little micro switch behind there
which again will change those contacts over okay so that also works for
tampering if somebody was to come along and actually just take those out
it would obviously indicate as well that they've been removed hopefully when we
get to the end of this we can simulate the failure by removing the device okay
that makes sense you are drawing in front of you as well
is that going to help explain the connections we're going to need to make
on the rig behind us yeah so the circuit i've designed here we're going to use
two industrial indicators 22 millimeter
holes holding there i've actually amazing how straight i got those holes
in there going i bet they didn't come already pre-cut into the enclosure did
they that's a top tip you can buy those enclosures pre-drilled
ready to take them normally you might see the start and stop button in there
okay so pick up this famous sketch okay um an ls
lousy okay brilliant sketch though yeah so we're going to take the neutral
conductor straight out to the indicators itself right common them up
on the back already there using the blue in the flex and then i've
got the common from the line conductor which is going to pick up in here we're
going to pick that we're going to rob that from the supply to the
metering device that's in there and then it's a case of taking the
normally open contact out to the fail lamp which is the red one
and that will not be illuminated under normal conditions that's it and then the
normally closed when everything's healthy we're going to
take it out to the green lamp and the green lamp will be permanently
illuminated under normal conditions that's
it okay so we've put the assembly here for our okay and failed indicators that
we saw on the bench we've passed our conductors
in and we've now got to make our connections for our permanent line and
neutral we've already picked up a line conductor
here using a double ferrule our cables coming down here through
these fuse sections then feed our meter and we thought it was best to come off
this fuse section here so i've just got to make the neutral connection here
but i've also got to join the neutral that we're needing for our indicator so
we're going to join those together in a double ferrule
if you haven't seen our video on improving electrical connections using
ferrules i recommend you check that one out
then what we've got to do is just follow it through so a line that we've already
made comes through to here and goes into our common connection and
then this side we've got a normally closed connection which we've got to
make for our green indicator and i normally open
on the other side for our failed indicator so we're going
to make those off as well so let's start off by doing this
double ferrule so i just need to strip back these cables
like so i'm going to twist the conductors together and just put a
double ferrule on it so we take those
i'm just going to twist them up and we're going to use a double ferrule
just improves that connection this makes it a little bit more secure where we're
going into the actual DIN rail itself take my ferrule crimping
tool
just bring that one up and then if i can see what i'm doing
i'm just going to pop that into there you can let my neutral up into there and
then it's just a matter of making two final connections
so that one's in like so and now we can just follow it through to
here and i know that when that goes in here
my connection this side is the normally closed and then we've
got the normally open and we've cleverly indicated them green
one for our normally closed and red one for our normally open need to take the
green one for unnormally closed to be the first
of our terminals a slightly smaller screwdriver in my hand
i can tighten those up and then we can do the red one
in our second terminal for our normally open
like so and then we just pop into the bottom of the surge and then we should
be able to indicate when that surge arrester's life is
expired so just pop that in under here and we're ready to see what happens when
we energize that up i think then what we can do is pull one of these out
that will effectively make it out to be a fail and we should see the lamps
change so powered up board we're under control
conditions we've got this panel removed we've got it removed i'm a little bit
concerned going i've got a red failed indicator on my side
good reason for that gary i've removed one of the surge protection devices and
that's mimicking a device failed which happened in
two ways either someone has removed the device and not replaced it
or if the device had had so many hits because of surges
it's the little red indicator appears but actually when that happens a
mechanical mechanism inside moves would move this little pin on the back
and trigger the micro switch in the same way so that moves forward allowing it
actually to pull out as we're in this position here so i'm hoping that when
you put that back in we close that circuit and the green
lamp will illuminate the same gary otherwise my diagram was wrong at the
start to put the module back in the light's change we
like that okay so there is there's one thing that i've
considered while we've been doing this we could have taken the actual feed from
the breaker that fed the surge and gone through and done our circuit
why would didn't we do that gordon okay well
that if someone had switched off the breaker then both lights would not be on
so then again you're relying on somebody's spot that actually
there's no lights on okay so in this case coming off a slightly different
circuit that was fused down that we thought we'd use it means that even
if you turn off the breaker for the surge we're actually still got a green
light indicated yes that's it okay yeah so yeah
so that could be a potential problem but i'm sure the viewers can sort that one
out so we're always interested in your
comments okay are you currently fitting surgery devices and how are you getting
on with doing that have you ever fitted an indicator lamp
or siren to show that the fact that it's failed
or in a healthy state would be interested in your comments below and
we'll try and get back to as many as we
can