so for this video circuit i would like to consider the use of a PIR when controlling
a lighting circuit so what a PIR stands for is passive infrared and so basically what
that is it's a detector that detects heat from the objects that passes through its field
and so it's basically just a switch so rather than having a manual switch that you just
turn on or on or off the the PIR does the switching for you we have a circuit breaker
or a fuse so we've got the PIR and we have the actual lights here so
the first thing to think about with a PIR generally there's four connections there's
usually a a supply supply live connection a switch live connection and then there's
usually two neutral connections but both of those neutral connections are linked together
so I'm just going to draw it as one here so the first thing to think about is the neutrals
so on this lighting circuit there's obviously going to be a neutral go into the PIR and
so that's all I'm going to join light actually gonna draw in the circuit and also on the
actual lights as well there will also be a neutral go into there there will also be a
CPC but I'm not going to draw those in this one so basically we've got the circuit breaker
which simply take a live feed to the PIR which again as you can see is just a switch and
then another feed going through the lights and that's how a basic PIR lighting circuit
is connected up remember the PIR has got electronic equipment inside so the more lights you have
the more load is being switched through the PIR so it's not really a great idea to have
too many light lights or too much load on the PIR where could this circuit be used well
I've I've installed it in people's houses before in in like I don't mean a garage or
a shed or in a utility room just as you walk in you could be carrying out and I say for
example in a utility room you walk in with a handful of washing rather than having to
turn on a light switch you can have a PIR either mounted on the wall or in the ceiling
and that picks you up and the lights turn on without you having to do anything PIR also
do have a couple of controls on them they have a time setting for when they how long
they're gonna stay on for sigh you know a minimum of maybe 5 seconds up to about sort
of a couple of minutes and they also have daylight and nighttime settings but but there
that's a relatively straightforward but the main thing is for this video is just to understand
the basic wiring for it and as you can see you don't get too much more basic than what
this is following on from the basic lighting circuit for a PIR I've now introduced a one
way switch and the idea of a one way switch is basically an override switch so again all
we have to do here is take a live feed so the permanent live feed here will come to
this one to the top of the switch and then we'll take another feed
from the switch feed from the PIR down to here
as you can see that's just two switches in parallel with one another and it's just an
override switch so this can now work in one of two ways you can have the normal PIR operating
so in this position the PIR will be operating so as soon as something is detected heat is
detected the switch will close and so electricity will flow through here through the switch
or through the switch and to the lights and the lights will turn on now the only issue
is is if the lights are if the PIR has only been set to operate for say maybe 10 seconds
and you've got this in a in a situation where you might want to be in the in the place for
more than 10 seconds you can do one of two things you can either operate the PIR you
you can either adjust the PIR to last longer or you can do a manual install a manual override
switch and all this is it's just a one way switch so as you can see now if we was to
operate the switch I was just to close it like so now what we have done is that we have
overridden the PIR so basically the connection is now through here to the PIR all the way
through down into the switch through the switch back up through the switch live connection
and then back to the lights and now the lights will stay on and so that's relatively quite
simple notice that we always have a permanent live supply going to the PIR it's important
that the PIR always has a permanent life supply go into it you never want to switch the permanent
life supply the reason being is that these have got all various electronic equipment
inside that needs to be reset sometimes and so if if you if you keep cutting the power
to the PIR and that will cause various issues one thing that I should have mentioned previously
as well is that the size of the circuit breaker obviously needs to reflect on the amount of
lights that are going to be there so normally this would probably be a six amp light and
normally a six amp circuit breaker for the lights but then you'd have to consider how
many lights you are gonna have so as I know you might just have two or three fluorescent
lights or LED's or whatever they are and usually this circuit here would be okay so hopefully
that one that's that video will be useful for someone