PIR - additional or replace switch?

[daveaspy]

I am thinking of putting a PIR in the attic bedroom to turn on the attic light automatically - currently there is a two-way light circuit with switches at the top and bottom of the stairs but I dont like having to find the top switch in the dark near some stairs! I am hopeful that sleeping movements from the bed on the other side of the room wont trigger the PIR. (current config is LN feed into top switch, 3 core down to bottom switch, 2 core from top switch up to ceiling rose)

I am wondering on different configurations:

1. Replace the top light switch and convert to a single switch at the bottom + PIR in parallel at the top
+keeps the switching easy to identify - "off" at the bottom switch means PIR is in control.
+can override PIR ON time using downstairs switch
- feels like there should still be a switch upstairs but I guess no real need? What if PIR fails?
- No way to force the light off as PIR can always trigger
- Cannot force the light on from upstairs

2. Keep the two-way and add the PIR in parallel
+ can override the PIR time limit from upstairs
+ can override the PIR time limit from downstairs
- No way of knowing if switch or PIR has the light turned on as two-way switches cannot indicate if they are "on"
- No way to force the light off.

3. Make bottom switch power up the whole circuit and top switch move between PIR or forced on
+ can force light off using downstairs switch
- cannot force light off from upstairs
- unusual switch layout, might need switches labelling
- lights wouldnt come on when turning bottom switch on (or do all PIRs trigger when first powered up?)

Is there a better option without adding additional switches? Option 2 biggest drawback is not knowing if the switches currently have the light on or the PIR so am swayed away from this. Its a kids bedroom if that makes any difference to the suitable options.

 

[EFLImpudence]

Silly idea.

Move attic switch to near the bed.

 

[daveaspy]

ha ha - thanks Funny how the simplest ideas often get overlooked! I'll have a think about that option - not sure about the routing. The LN feed to the top switch originates from somewhere close to the bed but the current junction point of the lamp/switches are far away (opposite wall). I'll try and scribble a drawing.

I think the least effort solution, without running new cables to both the ceiling rose and bottom light switch, it just to run a 3 core cable around the outside of the attic room (in the eaves storage space) and relocate the top switch to a suitable location. I need to investigate if it is possible to run a new cable to the rose and bottom switch without ripping the attic apart!

 

[AndyPRK]

Yeah keep it simple.

All you need to do is run a 3 core and earth cable to the existing switch.

If you wanted you could even fit an intermediate 3rd sw there or a blanking plate.

 

[daveaspy]

thanks Andy, switching the top to an intermediate could be the best plan to keep all bases covered