Wiring a PIR direct from the loop live?

[h00tsman]

Hi everyone,

Would first of all just like to say hi, I'm new to here and looking for some advice, and maybe help other in the future.

I have a little question.
I need to install a light in the hall, i don't want to put a switch on the wall, so was wondering if i could use a PIR.
I took the floor boards up above and found the lighting circuit, so was going to put a 5amp junction box there, run this to the ceiling mounted PIR and from this switching to the light about 1 meter away.

This is fine to do is it not?

Thanks.

 

[Taylortwocities]

Yes, except that the junction box must be accessible. Were you going to put laminated flooring, carpet, etc over the junction box?

 

[h00tsman]

The floor boards are not laminated, they can be taken up at any time.

I appreciate the help.
Thanks

 

[sparkwright]

Can you get the feed from an existing ceiling rose?

Are you certain the cable you are thinking about connecting into is a permanent live and neutral cable, and not a switch cable?

 

[h00tsman]

Right now I'm not 100% if it is the PL cable, I can find out with some chasing it back. Problem with taken it from another ceiling rose is there isn't one close...

On another note, can you recommend a good place to get flush ceiling mount PIR's?, I Was looking at CPelectronics and Screwfix.

Cheers

 

[ban-all-sheds]

i don't want to put a switch on the wall,

Why not?

so was wondering if i could use a PIR.

Will that always switch the light on soon enough no matter what direction you approach it from?

Will it always stay on long enough?

Will you never pass through the hall without wanting the light to come on?

 

[h00tsman]

It's a very old house, so didn't want to start chasing out the walls.

And the area the light needs to come on, must come on all the time the area is accessed. It's the old servants stairs and very dark. It's quite narrow, so you would be hard pushed to avoid detection.

As it's only a through path, the light can stay on for upto 10 minutes.

 

[bernardgreen]

It's quite narrow, so you would be hard pushed to avoid detection.

It may be the exact opposite

A person walking directly towards a sensor may not be detected as most sensors are less sensitive to targets moving towards them. PIRs are most sensitive to a target passing across the field of view. Narrow corridors may need two or more sensors, one at each end and wired in parallel with each other to detect people as they pass the sensor.

 

[ban-all-sheds]

It's a very old house, so didn't want to start chasing out the walls.

Too hard?

Too unstable?

And the area the light needs to come on, must come on all the time the area is accessed. It's the old servants stairs and very dark.

I wouldn't risk a PIR - put some wireless switches in if you don't want to chase the walls.

 

[h00tsman]

It isn't hard, its just preference. It's my parents place, so it's not like i want to cut corners.
I've never used wireless switches. Can you recommend any?

 

[bernardgreen]

This page explains the difference between motion detecting PIRs and presence detecting PIRs and is written by the company who developed the technology of PIRs

http://www.steinel.de/en/produkte_fuer_fachkunden/unterschiede_bewegung_praesenz

( It is written in English )

 

[JohnD]

To avoid chasing the walls, have you considered ceiling mounted pull-switches? If it is old servants stairs, you might even surface-mount the cable or use mini-trunking.

Or is it the complexity and difficulty of a PIR installation that appeals to you?