replacing a set of light switches in the stair way with PIR switches

[Deuce]

How much power does the PIR take 24/7? Maybe 3 watts. When only switching a smallish load such as 16 watts there is little saving over leaving the light on for the 8 hour day. That is before taking into account the initial cost and installation charges.

Such cynical thinking

I think more like 20ma or less for most compact sensors, so not really a consideration.

Also the existing fitting may not be led, so the change itself could bring a general saving.

Not to mention they may not want their stair light on all night.

 

[Octopus]

Thanks All for your replies, I think I'll get an electrician, thought it be a simple swap out, @Dillb , yes, I want to swap from normal switches to PIRs they'll be switching five 28W D5 fluorescent bulbs.

Is this a block of flats ?

5 x D5 would be very unusual in a house ...

 

[chris gray]

Just break the switch wire with the pir?

Gardeners use bulbs!!!

 

[Kaveh]

sorry about the late reply, to answer to your questions:

- yes it is in block of flats, and its 2D not D5, sorry

- this is the PIR Schneider Screwless Flat Plate Stainless Steel PIR Light Switch GUP1411BSS | RS Electrical Supplies - https://www.rselectricalsupplies.co.uk/schneider-screwless-flat-plate-stainless-steel-pir-light-switch-gup1411bss_10656?gclid=EAIaIQobChMI6-nfo7PO3QIVA7DtCh029QrrEAYYASABEgKy2PD_BwE/


It turns out that the PIR is not suitable for Florescent bulbs so I cant be used as intended.

I fitted it to the hallway which is connected to two x 40w halogen bulbs and I could hear a slight buzzing, it blew the PIR overnight so I guess it’s not suitable for halogens either...


So now I am thinking of something like this:

Kosnic 12W LED 2D 4PIN AMENITY REPLACEMENT SENSOR LAMPS - W40 - https://www.superlecdirect.com/p-kled12crd4pw40-kosnic-12w-led-2d-4pin-amenity-replacement-sensor-lamps-w40?gclid=EAIaIQobChMIvdGbhbbO3QIVqrztCh0RwAhvEAQYDCABEgKs8_D_BwE

 

[Deuce]

sorry about the late reply, to answer to your questions:

- yes it is in block of flats, and its 2D not D5, sorry

- this is the PIR Schneider Screwless Flat Plate Stainless Steel PIR Light Switch GUP1411BSS | RS Electrical Supplies - https://www.rselectricalsupplies.co.uk/schneider-screwless-flat-plate-stainless-steel-pir-light-switch-gup1411bss_10656?gclid=EAIaIQobChMI6-nfo7PO3QIVA7DtCh029QrrEAYYASABEgKy2PD_BwE/


It turns out that the PIR is not suitable for Florescent bulbs so I cant be used as intended.

I fitted it to the hallway which is connected to two x 40w halogen bulbs and I could hear a slight buzzing, it blew the PIR overnight so I guess it’s not suitable for halogens either...


So now I am thinking of something like this:

Kosnic 12W LED 2D 4PIN AMENITY REPLACEMENT SENSOR LAMPS - W40 - https://www.superlecdirect.com/p-kled12crd4pw40-kosnic-12w-led-2d-4pin-amenity-replacement-sensor-lamps-w40?gclid=EAIaIQobChMIvdGbhbbO3QIVqrztCh0RwAhvEAQYDCABEgKs8_D_BwE

You just need to build up a small box containing a timer relay, of whatever rating is required to handle the lighting load.

Something like this: RS Pro Multi Function 10 Timer Relay, Screw, 0.1 s → 100 h, SPDT, 1 Contacts, SPDT, 12 → 240 V ac/dc | RS Components - https://uk.rs-online.com/web/p/time-delay-relays/8966813/
That's 6 amp, but higher rated are available.

The PIR would send it's volt signal to the relay instead of turning on the lights directly, and you can configure the timer relay to energise energise the lighting circuit for a set length of time. If the PIR is still detecting movement the timer relay will keep the circuit energised indefinitely.

Hope this is some help for you.

 

[Kaveh]

thanks for the advice @Deuce