Two PIRs for one light?

[rantoftheday]

Is it possible to wire up a lighting cicuit so that there are two PIRs controlling one light so that if any PIR is activated the light comes on?

And if so does anyone have a wiring diagram for such a system?

 

[Richard Burns]

Yes common the line on one side and common the SL on the other. i.e. wire them in parallel to each other.
Pretty picture:

 

[rantoftheday]

thanks richard!

 

[HandySparks]

Looking at the diagram, I think you've got a spare piece of wire there. Only one connection needed on the Line side of the PIRs. No need for two cores in parallel.

 

[stansmith]

2 core feed neutral to the fitting the 3c between fitting and first pir and to second, depends on how your wiring it the picture above works (1 core too many) but you lose your permanent feed to the fitting which you may need unless thats the complete circuit mentioned and it isnt an emergency light, unless you use a 3core from pir to fitting shown in the drawing to continue the perm feed then problem solved.

 

[Richard Burns]

Oops! yes you are right as I drew the diagram I suddenly thought that the straight line did not make it clear and drew the junctioned line and forgot to remove the old one.
Thank you!

 

[gary234]

Looking at the diagram, I think you've got a spare piece of wire there. Only one connection needed on the Line side of the PIRs. No need for two cores in parallel.

Do you have an updated diagram now you have removed the extra wire??

 

[Richard Burns]

Updated diagram, obviously the cpc should connect everywhere appropriate but it would make the diagram too crowded.



(welcome to the forum, by the way)

 

[vernam616]

You could have a lot more than 2 PIRS if required, ive installed like this before within a commercial property, large room with 3-4 entrances

Take a 3core and earth from any light/fitting to the first pir then wire to the next and on and on and on.....

No matter which PIR is triggered it will send a switched live back through the 3core and other PIRs and switch the lights on

 

[i=p/u]

do you just add another feed on to the swithced live if you want a permnenant light on????

 

[1shortcircuit]

Take a 3core and earth from any light/fitting to the first pir then wire to the next and on and on and on.....

Never done this before but reading with interest :thumbsup

Sounds very similar to wiring an interlinked smoke/heat alarm circuit

 

[Guest112]

do you just add another feed on to the swithced live if you want a permnenant light on????

not sure what you mean there looking at the updated diagram the lamp will only have a switched live via either PIR but if this wasnt the end of the circuit you would need a 3 core from the pir to the lamp continuing the permanent feed say to the next room etc (obviously you wouldnt need a 3 core between rooms/differently switched circuits only a perm feed and neutral).

Do you mean adding another switched live from a switch onto the same switch wire to bring the lamp on like an overide switch to keep the lamp on? cant say ive ever installed an override switch to keep the lights on but have to kill the feed to the pir whenthe light isnt required, so if someone leaves the switch on the pir will turn off and then the switch can be turned off when the lights arent needed for whatever reason

 

[Richard Burns]

The diagram here is "feeding the switch" and is not really planned for an internal lighting loop in system, but if you were running this as part of a loop in system then you would loop in from the PIRs not the lamp (waste of cable).

You can have a manual override (not really allowed now for new outside lights, must be time and light controlled) and you are really just adding another switch but instead of a PIR use a manual switch; as mentioned above just more switches in parallel, even if the PIR operates it will not make a difference, just crate parallel feeds to the lamp.

diagram a bit messy now but..

this shows a couple of manual overrides.

 

[nabba]

Thanks Richard for the info . Much help..

 

[i=p/u]

Good work burnsy and others.

 

[nabba]

Taking a 3 core from fitting to pir , and so on and on to the next pir or multiple whatever the case , are you suggesting a 3 core providing the fitting your coming from is possibly a EM fitting or has a looped perminant feed as you would need a perminant live also to each pir, ?
Just was trying to understand the way you wrote it As it wasn't stated in your post
Thanks

 

[nabba]

Hi Richard I have looked at your overide switches, I need to install one in a small office the lights are switched via a motion sensor at the moment but need a switch to turn off the lights when a projector is in use when in meeting, looking at your drawings paralleling a manual switch this way would it work??? Never installed a overide switch before would I not have to kill the perm feed to sensor??

 

[Guest111]

There are 2 ways to do what you want,either install your switch in the perm live to the sensor or in the switched live from the sensor.When we talk about an override switch on pir,s it is normally to make the light stay on and is wired across the perm live and switched live,what you want is really a cut out switch to prevent pir from switching light on,hope this helps.

 

[Richard Burns]

I would put a switch in the switched live going to the light (after the PIR) because then the sensor will not need to be restarted each time.

 

[nabba]

Hi Richard , still wet behind the ears from collage so just a guide pls if you would 4 PIRs on one lighting circuit so in order to make either sensor switch lights on , as your drawing would I just parallel up all PIRs first ? then off to my lights or could I just loop in and out through my lights as I go till I get to next pir and so on , as long as all perminant wires and switch wires go we're they need to go ?

Thanks