Positioning intruder PIR's

Dirk · 6 Feb 2005

I want to put some wires in place so that in the future I can wire up an alarm system.
Can somebody tell me what the best position is for PIR's and the places to avoid putting them so as not to get a false alarm.
Cheers.

breezer · 6 Feb 2005

in the corner preferably near window looking in, so that it is NOT looking at the window.

not above rads, open fires air vents etc

andy · 6 Feb 2005

Dirk said:
I want to put some wires in place so that in the future I can wire up an alarm system.
Can somebody tell me what the best position is for PIR's and the places to avoid putting them so as not to get a false alarm.
Cheers.

put in most downstairs rooms. i.e passage, kitchen, sitting room etc. as breezer said, not facing a window as it may pick up people outside

breezer · 6 Feb 2005

andrew2022 said:
, not facing a window as it may pick up people outside

err, sorry about this, that is not the reason.

a P.I.R. can not see through a solid object, glass being a solid object.

you position them away from glass as the sun will heat the glass, this the pir will see and cause an activation.
Also to a P.I.R. glass will act as a mirror, enabling it to see some where it shouldn't

andy · 6 Feb 2005

breezer said:
andrew2022 said:

, not facing a window as it may pick up people outside

Click to expand...

err, sorry about this, that is not the reason.

a P.I.R. can not see through a solid object, glass being a solid object.

you position them away from glass as the sun will heat the glass, this the pir will see and cause an activation.
Also to a P.I.R. glass will act as a mirror, enabling it to see some where it shouldn't

i always thought it could see thru glass

breezer · 6 Feb 2005

no sorry it can't a microwave detector can though, no problem

Dirk · 6 Feb 2005

Cheers fella's, it shouldn't be a problem locating them downstairs as I live in a bungalow!.

mrgrumpy · 6 Feb 2005

Dirk said:
I want to put some wires in place so that in the future I can wire up an alarm system.
Can somebody tell me what the best position is for PIR's and the places to avoid putting them so as not to get a false alarm.
Cheers.

One important thing!.......don't run alarm cable next to mains a/c cable!

Or you will have lots of false alarms.

Lectrician · 6 Feb 2005

You would only get false alarms if it was on an ID loop or similar. BUT you should still segregate the two cables to prevent dangerous voltages appearing on the alarm cable due to induction.

breezer · 6 Feb 2005

Lectrician said:
You would only get false alarms if it was on an ID loop or similar

not true, most microprocessor panels do not like induced voltages.

to quote Mr jones from dads army "they don't like it up 'em"

Lectrician · 6 Feb 2005

Most manuals tell you to seperate the cables accordingly, but to take extra care on ID loops.

mrgrumpy · 6 Feb 2005

Lectrician said:
You would only get false alarms if it was on an ID loop or similar. BUT you should still segregate the two cables to prevent dangerous voltages appearing on the alarm cable due to induction.

Alarms work on low voltage, and full of sensitive CMOS chips, so any a/c induced voltage will trigger the alarm panel. ID chips are programmed individually so they can't trigger the alarm unless it sends it's identity. I was once called to a house the electrician had run the alarm cable with the mains on the first fix, the alarm constantly triggered. We had to power it down and the owner said get rid of it!

diynot

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local

Positioning intruder PIR's

breezer

breezer

breezer

breezer

Similar threads