I have an outside light that is switched from inside the house but I now want it to be switched also by an external PIR that runs on 240 volts. I don't want to use two-way switches but want to know if its is safe/feasible to do this ie have the light fitting supplied with two potentially live wires and two neutrals.

What I want to achieve is the ability to have the light switched on by the internal switch and left on for say a couple of hours - irrespective of what the PIR does. The internal switch is not intended to over-ride or control what the PIR does.

:
I have an outside light that is switched from inside the house but I
now want it to be switched also by an external PIR that runs on 240
volts. I don't want to use two-way switches but want to know if its is
safe/feasible to do this ie have the light fitting supplied with two
potentially live wires and two neutrals.

Should be OK but just make sure that the switch and PIR are on the same
circuit from the CU. Every PIR I've used has a relay (I can hear it
click on/off) and that would certainly be OK as you've effectively just
got two switches in parallel.

What I want to achieve is the ability to have the light switched on by
the internal switch and left on for say a couple of hours -
irrespective of what the PIR does.

With you so far...

The internal switch is not intended to over-ride or control what the
PIR does.

Surely when the switch is on it *does* override the PIR.

--
Mike Barnes

On Thu, 5 Apr 2012 03:15:00 -0700 (PDT)
wrote:

I have an outside light that is switched from inside the house but I
now want it to be switched also by an external PIR that runs on 240
volts.

It's quite likely you can achieve this by just adding the PIR in series
with the switch. Many PIR's have the ability to stay on continuously by
just flicking the switch "off - on" quickly, with some of them you
might need "off - on - off - on". It will then stay on until you
turn the switch off and then revert to automatic when you switch it on
again.

--
Mike Clarke

On Thu, 5 Apr 2012 12:54:31 +0100, Mike Clarke wrote:

It's quite likely you can achieve this by just adding the PIR in series
with the switch. Many PIR's have the ability to stay on continuously by
just flicking the switch "off - on" quickly, with some of them you
might need "off - on - off - on". It will then stay on until you
turn the switch off and then revert to automatic when you switch it on
again.

True enough but the OP had a timed requirement for the non-PIR
controlled on state.

--
Cheers
Dave.

Surely when the switch is on it *does* override the PIR.

Mike Barnes

What I meant was that if the switch was on, then the PIR could not
switch the light off when it was triggered ie it would not act like a
two way switch.

Yvonne :
Surely when the switch is on it *does* override the PIR.

Mike Barnes

What I meant was that if the switch was on, then the PIR could not
switch the light off when it was triggered ie it would not act like a
two way switch.

Fair enough, you should be OK then. I have a similar setup here and it
works fine.

--
Mike Barnes

On Thu, 05 Apr 2012 12:54:31 +0100, Mike Clarke
wrote:

On Thu, 5 Apr 2012 03:15:00 -0700 (PDT)
wrote:

I have an outside light that is switched from inside the house but I
now want it to be switched also by an external PIR that runs on 240
volts.

It's quite likely you can achieve this by just adding the PIR in series
with the switch.

Parallel shurely?

Jim K

On Thu, 05 Apr 2012 14:31:43 +0100
"Jim K" wrote:

On Thu, 05 Apr 2012 12:54:31 +0100, Mike Clarke
wrote:

On Thu, 5 Apr 2012 03:15:00 -0700 (PDT)
wrote:

I have an outside light that is switched from inside the house but
I now want it to be switched also by an external PIR that runs on
240 volts.

It's quite likely you can achieve this by just adding the PIR in
series with the switch.

Parallel shurely?

Jim K

No, it needs to be in series.

When the switch is on the light is under control of the PIR
When the switch is off the light will be off regardless what the PIR
thinks
When you do the magic "off - on" or "off - on - off - on" gymnastics the
PIR will leave the light on all the time until you reset it.

--
Mike Clarke

Mike Clarke wrote:

On Thu, 05 Apr 2012 14:31:43 +0100
"Jim K" wrote:

It's quite likely you can achieve this by just adding the PIR in
series with the switch.

Parallel shurely?

No, it needs to be in series.

When the switch is on the light is under control of the PIR
When the switch is off the light will be off regardless what the PIR
thinks
When you do the magic "off - on" or "off - on - off - on" gymnastics the
PIR will leave the light on all the time until you reset it.

The "interrupt to turn on" method varies between devices. Mine,
for instance, turn itself off again after a couple of minutes.

Look back at what to OP wants:

What I want to achieve is the ability to have the light switched on by the internal switch and left on for say a couple of hours - irrespective of what the PIR does.

Which seems clear enough, but then:

The internal switch is not intended to over-ride or control what the PIR does.

which muddies the waters again. If it doesn't over ride, how is
anything going to work? I think this is just badly expressed.

Nevertheless, I'll vote for parallel too.

Chris
--
Chris J Dixon Nottingham UK


Have dancing shoes, will ceilidh.

On 05/04/2012 11:15, wrote:

I have an outside light that is switched from inside the house but I now want it
to be switched also by an external PIR that runs on 240 volts. I don't want to
use two-way switches but want to know if its is safe/feasible to do this ie have
the light fitting supplied with two potentially live wires and two neutrals.

What I want to achieve is the ability to have the light switched on by the
internal switch and left on for say a couple of hours - irrespective of what the
PIR does. The internal switch is not intended to over-ride or control what the
PIR does.

Yup, easy enough:

http://wiki.diyfaq.org.uk/index.php?...ng_ with_PIRs




--
Cheers,

John.

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On Thu, 05 Apr 2012 15:26:50 +0100
Chris J Dixon wrote:

The "interrupt to turn on" method varies between devices. Mine,
for instance, turn itself off again after a couple of minutes.

It does seem to vary a bit between models. I have 2, one stays on
indefinitely and the other goes back to auto at dawn.

Look back at what to OP wants:

What I want to achieve is the ability to have the light switched on
by the internal switch and left on for say a couple of hours -
irrespective of what the PIR does.

Which seems clear enough,

But in a later post she added:

What I meant was that if the switch was on, then the PIR could not
switch the light off when it was triggered

Which is exactly the way that mine behaves.

Nevertheless, I'll vote for parallel too.

Except that it will require extra cabling to be installed. The
"interrupt to turn on" method avoids this, or at least reduces the extra
cabling requirement.

Chris



--
Mike Clarke

In article , John
Rumm writes
On 05/04/2012 11:15, wrote:

I have an outside light that is switched from inside the house but I now want it
to be switched also by an external PIR that runs on 240 volts. I don't want to
use two-way switches but want to know if its is safe/feasible to do this ie have
the light fitting supplied with two potentially live wires and two neutrals.

What I want to achieve is the ability to have the light switched on by the
internal switch and left on for say a couple of hours - irrespective of what the
PIR does. The internal switch is not intended to over-ride or control what the
PIR does.

Yup, easy enough:

http://wiki.diyfaq.org.uk/index.php?...witching_ wit
h_PIRs

Don't think the article says it explicitly but I think the PIR will need
to be a relay based one (ie one with a neutral). The non relay ones self
power by dropping a little power from the series connection with the
lamp either on or off so bypassing a non-relay PIR with a switch may
cause problems.
--
fred
it's a ba-na-na . . . .

On 05/04/2012 15:48, Mike Clarke wrote:
On Thu, 05 Apr 2012 15:26:50 +0100
Chris J wrote:

The "interrupt to turn on" method varies between devices. Mine,
for instance, turn itself off again after a couple of minutes.

It does seem to vary a bit between models. I have 2, one stays on
indefinitely and the other goes back to auto at dawn.

Look back at what to OP wants:

What I want to achieve is the ability to have the light switched on
by the internal switch and left on for say a couple of hours -
irrespective of what the PIR does.

Which seems clear enough,

But in a later post she added:

What I meant was that if the switch was on, then the PIR could not
switch the light off when it was triggered

Which is exactly the way that mine behaves.

Nevertheless, I'll vote for parallel too.

Except that it will require extra cabling to be installed. The
"interrupt to turn on" method avoids this, or at least reduces the extra
cabling requirement.

Basically you are both right... The series solution would work for PIRs
that allow the toggle to latch on fandango (IME a bit of a mixed
blessing - one power glitch and they are often then locked on!). With a
PIR that does not support this, then the parallel arrangement like that
in the wiki is the way (and would work with both types of PIR).


--
Cheers,

John.

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| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On 05/04/2012 17:21, fred wrote:
In article , John
Rumm writes
On 05/04/2012 11:15, wrote:

I have an outside light that is switched from inside the house but I
now want it
to be switched also by an external PIR that runs on 240 volts. I
don't want to
use two-way switches but want to know if its is safe/feasible to do
this ie have
the light fitting supplied with two potentially live wires and two
neutrals.

What I want to achieve is the ability to have the light switched on
by the
internal switch and left on for say a couple of hours - irrespective
of what the
PIR does. The internal switch is not intended to over-ride or control
what the
PIR does.

Yup, easy enough:

http://wiki.diyfaq.org.uk/index.php?...witching_ wit

h_PIRs

Don't think the article says it explicitly but I think the PIR will need
to be a relay based one (ie one with a neutral). The non relay ones self
power by dropping a little power from the series connection with the
lamp either on or off so bypassing a non-relay PIR with a switch may
cause problems.

Yup you are right. Aside from the ones designed to replace a light
switch, most of them require L&N and hence are suitable. Even the
internal ones built into some lamps can usually be rigged to run like
this, although you need to watch the switched load since their relays
are usually fairly small.

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On Thu, 05 Apr 2012 17:21:55 +0100
John Rumm wrote:

The series solution would work for PIRs
that allow the toggle to latch on fandango (IME a bit of a mixed
blessing - one power glitch and they are often then locked on!).

I think that's why some of them have gone over to needing an "off - on -
off - on" sequence.

--
Mike Clarke