Didn't mean to offend, just saying that i couldn't see why i shouldn't put 2 PIRs in some zones. I'm used to fault finding on circuits (its what i do for a living) so it's something i'm prepared to do if i have a fault in one of those zones.

I'm aware of a few of the minor things, such as making sure that where the cable enters a PIR is totally sealed. I know that spiders can get through the most tiny gap and will cause havock with a PIR. What other minor things are there to consider?

Without giving out all we know, the siting of the detectors, pet immune does not mean that if incorrectly fitted, are there radiators in view list is endless.

All minor, yet add up to a major problem if not thought about. Chasing shorts in circuits isnt the be all and end all of doing this stuff.

Didn't mean to offend, just saying that i couldn't see why i shouldn't put 2 PIRs in some zones.

You can please your self on this matter as you don't have to cert it... the rules where / maybe still are maxium of ten contacts on a zone, ten pir on a e/e zone, ten latchingpir....

What other minor things are there to consider?

gob cable hole in wall up, looking in room where possiable, not near or looking at stuff that moves or source of heat eg looking at a coal fire cables away from mains ect...

You can please your self on this matter as you don't have to cert it... the rules where / maybe still are maxium of ten contacts on a zone, ten pir on a e/e zone, ten latchingpir....

gob cable hole in wall up, looking in room where possiable, not near or looking at stuff that moves or source of heat eg looking at a coal fire cables away from mains ect...

The PIRs aren't latching but i have placed all PIRs facing into the rooms not looking at radiators or sources of heat (one exception is the hall PIR which looks down the hall at the front door but since the sun never faces the door i'm hoping that it'll be ok). I've already filled the cable holes with silicon sealer (thought that if i plaster/fillered the holes i might need to pull some cable through at a later date and have to get it out again and it'd be a bitch). All cables have been ran away from mains, they only cross mains at right angles. There aren't any runs parallel with mains. I'm thinking of putting it on soak test for a few days just to make sure i haven't got any areas of false alarms and i don't want to annoy the neighbours.

The way you have done it , you still have 1 spare zone, you could at least split one of your double detector zones.

Personally if I were you I would put the back door contact and kitchen window shock on the same zone and put all pirs on their own zones. The shock sensor should be latching.

Techincally you can have 10 devices on one zone, its how to identify the tripped one is the trick.

i don't know a reason why would it be limited to 10.. only if you are going to install them in the doll house they might not fit inside...

Didn't mean to offend, just saying that i couldn't see why i shouldn't put 2 PIRs in some zones. I'm used to fault finding on circuits (its what i do for a living) so it's something i'm prepared to do if i have a fault in one of those zones.

you install these expensive CNC machines wrong way so you can go later and fault find later???

usually we try to do it right at first time..

I'm aware of a few of the minor things, such as making sure that where the cable enters a PIR is totally sealed. I know that spiders can get through the most tiny gap and will cause havock with a PIR. What other minor things are there to consider?

infrared sources

i don't know a reason why would it be limited to 10.. only if you are going to install them in the doll house they might not fit inside...

BS 47437 1988........ Dolls house? on the vodka (again)

Its only PIRs?????

Slightly different to an expensive machine. Well i'm following the manual so other than an IF one of the PIRs on the zones with 2 on it goes a bit iffy i can't see that i should have any problems.

Its only PIRs?????

True....... as I said before....

You can please your self on this matter as you don't have to cert it

The mains is a direct feed from the consumer unit from its own 6A MCB through a 3A fused outlet box.

OK, i understand now that from a professional point of view one PIR per zone makes sense as it rules out all guess work when it comes to fault finding. I was just getting the feeling that i had committed a great sin by putting 2 PIRs into one zone. This is the first (and probably last) alarm system that i've fitted and i've followed the engineers guide to the letter. I've followed advice about sealing the cable entries of the PIRs and been careful to site the PIRs so they're not facing windows or radiators (at the expense of having to make some difficult cable runs over the easy options). I felt that i was being made to feel a noob for putting 2 PIRs into 1 zone even though the engineers guide says its ok and shows how to do it.

Thanks for the advice all. The system is on soak test and i've had a false alarm free night so far.

Edited October 15, 200619 yr by SnowBum