On Wed, 1 Apr 2020 12:18:42 +0100, John Rumm wrote:

On 01/04/2020 09:12, Robin wrote:
On 01/04/2020 02:04, John Rumm wrote:
On 31/03/2020 23:22, petek wrote:
On Monday, March 30, 2020 at 11:00:42 PM UTC+1, petek wrote:
I'm hoping to install 3 outside LED light fittings controlled by 2
PIR switches - all lights to come on if either of the switches
triggers. I've done a cursory search on t'internet but can't find
any 2 way PIRs. The ones I've seen don't mention if they are 1 or 2
way so I presume they must be 1 way. Can anyone recommend or post a
link to a suitable 2 way PIR?

Thanks Pete

Thanks to all for your comments and explanations. I saw the Wiki but
misunderstood the diagram. I thought it was similar to 2 way wiring
at the top/bottom of a staircase for example. I now understand thanks
to you guys. I like the look of the TLC ones mentioned by John but
Robin comments that I should check if they are suitable for wiring in
parallel. How do I do this?

You may be able to download the manuals - but they may not mention it
either way. Chances are they will work just fine. (I have not found
any that did not)


If you look at the instructions for the TLC one I posted a link to:

https://www.tlc-direct.co.uk/Technic...structions.pdf


the lower wiring diagram shows using a switch to provide an "always
on" bypass. So that will definitely work (it can't tell if the bypass
switch is a manual one or another PIR).

Here is another:

https://www.tlc-direct.co.uk/Technic...witch/6016.pdf

Again bypass shown as a wiring option - making the PIR switched live
output live by external means.



I agree (of course) but just to check that my memory wasn't /that/ far
gone I've dug back and found the ones I had to return (because I didn't
RTFM before buying) because the instns said they couldn't be wired in
parallel.* Turns out they were 2-wire Clipsal 750WP.* And it was even
longer ago than I'd thought.

http://www.hunters-wholesalers.co.uk/images/W507.pdf

Yup 2 wire is a different beast - with no neutral reference, it needs to
bleed a small current through the load even when "off" to allow it to
self power. If you make the output live externally, then it now has two
live connections and no neutral - in effect turning the non active
device completely off.

That may in practice still work after a fashion[1] - each being able to
turn the lights on - but you would lose that "wired OR" functionality
that would allow both devices to be triggered, and the lights only go
off when the last PIR reaches the end of its preset "on" time.

I don't know if this always applies: when deciding on a PIR I've looked for
it being OK with CFL, on the assumption that it has a relay.

[1] however if the PIR is the type which turns the lamps on at power up,
then you would likely get them powering up and down in alternation for
ever more!


--
Peter.
The gods will stay away
whilst religions hold sway