I am changing an extraction fan with timer.
The old fan has 2 red and a black wire but no indication as to what one
is live switch, how do I determine what one of the reds is live switch,
with the power switch off at mains.

ss Wrote in message:
I am changing an extraction fan with timer.
The old fan has 2 red and a black wire but no indication as to what one
is live switch, how do I determine what one of the reds is live switch,
with the power switch off at mains.


Switch power on at mains, test each wire.
--
Jim K


----Android NewsGroup Reader----
http://usenet.sinaapp.com/

On Sat, 01 Jun 2019 23:49:31 +0100, Jim K.. wrote:

ss Wrote in message:
I am changing an extraction fan with timer.
The old fan has 2 red and a black wire but no indication as to what one
is live switch, how do I determine what one of the reds is live switch,
with the power switch off at mains.


Switch power on at mains, test each wire.

Insufficient advice. Doesn't allow for eliminating false positives
("ghost voltages").



--
Leave first - THEN negotiate!

On 01/06/2019 23:16, ss wrote:
I am changing an extraction fan with timer.
The old fan has 2 red and a black wire but no indication as to what one
is live switch, how do I determine what one of the reds is live switch,
with the power switch off at mains.

Easy way - look at which is connected to the existing switched live
terminal on the fan, then mark it with tape before disconnecting. :-)


--
Cheers,

John.

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

On 01/06/2019 23:16, ss wrote:
I am changing an extraction fan with timer.
The old fan has 2 red and a black wire but no indication as to what one
is live switch, how do I determine what one of the reds is live switch,
with the power switch off at mains.

I would be tempted to make a guess knowing there's a 50% likelihood of
it being right!

Yes it was maybe something that they should have done before taking the old
unit out using a meter with a probe assuming of course te on situation is
controllable and is not some function of a thermostat, but then I think if
one is live and one not you have your answer if everything is cold at the
time.
Brian

--
----- --
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please
Note this Signature is meaningless.!
"Jim K.." wrote in message
o.uk...
ss Wrote in message:
I am changing an extraction fan with timer.
The old fan has 2 red and a black wire but no indication as to what one
is live switch, how do I determine what one of the reds is live switch,
with the power switch off at mains.


Switch power on at mains, test each wire.
--
Jim K


----Android NewsGroup Reader----
http://usenet.sinaapp.com/

On 02/06/2019 07:52, Brian Gaff wrote:
Yes it was maybe something that they should have done before taking the old
unit out using a meter with a probe assuming of course te on situation is
controllable and is not some function of a thermostat, but then I think if
one is live and one not you have your answer if everything is cold at the
time.
Brian

I agree however I did mark one of the reds so when I took the old fan
down I could then match it up with the identification markings on the
fan, only then did I discover the old fan is marked N and L but nothing
for the 3rd wire.
I did take a picture before disconnecting but that doesnt solve it due
to lack of identification markings.

Cursitor Doom Wrote in message:
On Sat, 01 Jun 2019 23:49:31 +0100, Jim K.. wrote:

ss Wrote in message:
I am changing an extraction fan with timer.
The old fan has 2 red and a black wire but no indication as to what one
is live switch, how do I determine what one of the reds is live switch,
with the power switch off at mains.


Switch power on at mains, test each wire.

Insufficient advice. Doesn't allow for eliminating false positives
("ghost voltages").




Follow given advice. Return if "ghost voltages" exist. FFS...
--
Jim K


----Android NewsGroup Reader----
http://usenet.sinaapp.com/

On 01/06/2019 23:16, ss wrote:
I am changing an extraction fan with timer.
The old fan has 2 red and a black wire but no indication as to what one
is live switch, how do I determine what one of the reds is live switch,
with the power switch off at mains.

Stick a bulb across, one of the lives and neutral. Then put the power
back on.

Either the bulb will be controlled by the light switch or not
(permanently on).

--
Adrian C

On 02/06/2019 08:54, Adrian Caspersz wrote:
Stick a bulb across, one of the lives and neutral. Then put the power
back on.

Either the bulb will be controlled by the light switch or not
(permanently on).

I assume using my cheap multimeter I could do the same and check for
voltage?

On 02/06/2019 09:02, ss wrote:
On 02/06/2019 08:54, Adrian Caspersz wrote:
Stick a bulb across, one of the lives and neutral. Then put the power
back on.

Either the bulb will be controlled by the light switch or not
(permanently on).

I assume using my cheap multimeter I could do the same and check for
voltage?

Yes. Look for changes when you 'modulate' the light switch.

--
Adrian C

On Sun, 02 Jun 2019 09:05:10 +0100, Adrian Caspersz wrote:

On 02/06/2019 09:02, ss wrote:
On 02/06/2019 08:54, Adrian Caspersz wrote:

I assume using my cheap multimeter I could do the same and check for
voltage?

Yes. Look for changes when you 'modulate' the light switch.

Yes, but not with a "cheap multimeter" - those ones typically pay zero
attention to proper mains isolation despite their self-declared CAT
ratings and have no MOVs etc.


--
Leave first - THEN negotiate!

Cursitor Doom Wrote in message:
On Sun, 02 Jun 2019 09:05:10 +0100, Adrian Caspersz wrote:

On 02/06/2019 09:02, ss wrote:
On 02/06/2019 08:54, Adrian Caspersz wrote:

I assume using my cheap multimeter I could do the same and check for
voltage?

Yes. Look for changes when you 'modulate' the light switch.

Yes, but not with a "cheap multimeter" - those ones typically pay zero
attention to proper mains isolation despite their self-declared CAT
ratings and have no MOVs etc.



How much should the op spend on a "proper multimeter" to do the
job properly?
--
Jim K


----Android NewsGroup Reader----
http://usenet.sinaapp.com/

On 02/06/2019 09:02, ss wrote:
On 02/06/2019 08:54, Adrian Caspersz wrote:
Stick a bulb across, one of the lives and neutral. Then put the power
back on.

Either the bulb will be controlled by the light switch or not
(permanently on).

I assume using my cheap multimeter I could do the same and check for
voltage?

Not too cheap, some don't really like mains even though they have a big
AC range.
They don't have enough insulation to be safe.
I certainly wouldn't use the £1.99 ones I bought on mains if I had to
touch them.

On Sun, 02 Jun 2019 11:03:03 +0100, Jim K.. wrote:

How much should the op spend on a "proper multimeter" to do the
job properly?

You don't have to spend a fortune. I use one of these for anything to do
with the mains: https://tinyurl.com/y49d475v

But cheaper still options are available.



--
Leave first - THEN negotiate!

On 02/06/2019 10:47, Cursitor Doom wrote:
On Sun, 02 Jun 2019 09:05:10 +0100, Adrian Caspersz wrote:

On 02/06/2019 09:02, ss wrote:
On 02/06/2019 08:54, Adrian Caspersz wrote:

I assume using my cheap multimeter I could do the same and check for
voltage?

Yes. Look for changes when you 'modulate' the light switch.

Yes, but not with a "cheap multimeter" - those ones typically pay zero
attention to proper mains isolation despite their self-declared CAT
ratings and have no MOVs etc.

You don't touch any metal parts of a "cheap multimeter" as they are all
plastic apart from the metal parts of the probes.

--
Max Demian

On 02/06/2019 11:03, Jim K.. wrote:
Cursitor Doom Wrote in message:
On Sun, 02 Jun 2019 09:05:10 +0100, Adrian Caspersz wrote:

On 02/06/2019 09:02, ss wrote:
On 02/06/2019 08:54, Adrian Caspersz wrote:

I assume using my cheap multimeter I could do the same and check for
voltage?

Yes. Look for changes when you 'modulate' the light switch.

Yes, but not with a "cheap multimeter" - those ones typically pay zero
attention to proper mains isolation despite their self-declared CAT
ratings and have no MOVs etc.



How much should the op spend on a "proper multimeter" to do the
job properly?

For this application a non contact volt stick will work well:

https://www.tlc-direct.co.uk/Products/TMPL107.html

or

https://cpc.farnell.com/c/test-equip...ters-detectors


--
Cheers,

John.

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

On 02/06/2019 14:40, Max Demian wrote:
On 02/06/2019 10:47, Cursitor Doom wrote:
On Sun, 02 Jun 2019 09:05:10 +0100, Adrian Caspersz wrote:

On 02/06/2019 09:02, ss wrote:
On 02/06/2019 08:54, Adrian Caspersz wrote:

I assume using my cheap multimeter I could do the same and check for
voltage?

Yes. Look for changes when you 'modulate' the light switch.

Yes, but not with a "cheap multimeter" - those ones typically pay zero
attention to proper mains isolation despite their self-declared CAT
ratings and have no MOVs etc.

You don't touch any metal parts of a "cheap multimeter" as they are all
plastic apart from the metal parts of the probes.


Leads are a suspect as well.

I was wondering what was constantly draining our car battery, and what
current it was - expecting a few 10's of milliamps drawn.

Erm no.

With a series connection I found I had rather more. Amazon's finest 99p
test leads have a nifty built in detection feature.


Smoke....

(I now have a decent clamp meter that does DC)

--
Adrian C

On Sun, 02 Jun 2019 14:54:15 +0100, Adrian Caspersz wrote:

Leads are a suspect as well.

I was wondering what was constantly draining our car battery, and what
current it was - expecting a few 10's of milliamps drawn.

Erm no.

With a series connection I found I had rather more. Amazon's finest 99p
test leads have a nifty built in detection feature.

Which is why I bought a Fluke 179.



--
My posts are my copyright and if @diy_forums or Home Owners' Hub
wish to copy them they can pay me £1 a message.
Use the BIG mirror service in the UK: http://www.mirrorservice.org
*lightning surge protection* - a w_tom conductor

On 02/06/2019 02:21, Fredxx wrote:
On 01/06/2019 23:16, ss wrote:
I am changing an extraction fan with timer.
The old fan has 2 red and a black wire but no indication as to what
one is live switch, how do I determine what one of the reds is live
switch, with the power switch off at mains.

I would be tempted to make a guess knowing there's a 50% likelihood of
it being right!

+1

Timer works, job done.
Timer does not work - then swap the reds over.

--
Adam

On 02/06/2019 14:49, John Rumm wrote:
For this application a non contact volt stick will work well

Yes I have one of those.

Max Demian wrote:

On 02/06/2019 10:47, Cursitor Doom wrote:
On Sun, 02 Jun 2019 09:05:10 +0100, Adrian Caspersz wrote:

On 02/06/2019 09:02, ss wrote:
On 02/06/2019 08:54, Adrian Caspersz wrote:

I assume using my cheap multimeter I could do the same and check for
voltage?

Yes. Look for changes when you 'modulate' the light switch.

Yes, but not with a "cheap multimeter" - those ones typically pay zero
attention to proper mains isolation despite their self-declared CAT
ratings and have no MOVs etc.

You don't touch any metal parts of a "cheap multimeter" as they are all
plastic apart from the metal parts of the probes.

You may be able to touch metal parts when the case melts though.

--

Roger Hayter

On 02/06/2019 11:26, dennis@home wrote:
I certainly wouldn't use the £1.99 ones I bought on mains if I had to
touch them.

Issue now sorted having identified the correct wires.

On 02/06/2019 16:19, Roger Hayter wrote:
Max Demian wrote:

On 02/06/2019 10:47, Cursitor Doom wrote:
On Sun, 02 Jun 2019 09:05:10 +0100, Adrian Caspersz wrote:

On 02/06/2019 09:02, ss wrote:
On 02/06/2019 08:54, Adrian Caspersz wrote:

I assume using my cheap multimeter I could do the same and check for
voltage?

Yes. Look for changes when you 'modulate' the light switch.

Yes, but not with a "cheap multimeter" - those ones typically pay zero
attention to proper mains isolation despite their self-declared CAT
ratings and have no MOVs etc.

You don't touch any metal parts of a "cheap multimeter" as they are all
plastic apart from the metal parts of the probes.

You may be able to touch metal parts when the case melts though.

Or pick them out of your face, when it flashed over internally...


--
Cheers,

John.

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

On 02/06/2019 12:52, Cursitor Doom wrote:
On Sun, 02 Jun 2019 11:03:03 +0100, Jim K.. wrote:

How much should the op spend on a "proper multimeter" to do the
job properly?

You don't have to spend a fortune. I use one of these for anything to do
with the mains: https://tinyurl.com/y49d475v

But cheaper still options are available.

The Fluke 101 could be worth considering. Joe Smith ran a series of high
voltage tests on a range of "cheap" (under 50 USD) multimeters and this
was a clear winner after testing up to 13 KV.
https://www.youtube.com/watch?v=RBkjr3b5hQo

Officially this isn't available in the UK but can be found from
apparently reputable UK suppliers on Ebay for under £50.

It has rather limited features so might not meet everyone's needs. In
particular it does NOT measure current but this has the advantage that
there's no danger of putting it across the mains with the leads in the
'amps' socket because there isn't one.

ss Wrote in message:
On 02/06/2019 14:49, John Rumm wrote:
For this application a non contact volt stick will work well

Yes I have one of those.


Rather begs the question, why do you have one? given your op...
--
Jim K


----Android NewsGroup Reader----
http://usenet.sinaapp.com/

On 03/06/2019 12:37, Jim K.. wrote:
For this application a non contact volt stick will work well
Yes I have one of those.

Rather begs the question, why do you have one? given your op...
--

Because even for something like changing a wall socket or light switch I
switch the mains off and double check with volt stick.
My safety drill far outways my electrical knowledge.

On 03/06/2019 14:52, ss wrote:
On 03/06/2019 12:37, Jim K.. wrote:
For this application a non contact volt stick will work well
Yes I have one of those.

Rather begs the question, why do you have one? given your op...
--

Because even for something like changing a wall socket or light switch I
switch the mains off and double check with volt stick.
My safety drill far outways my electrical knowledge.

I think John meant that you can reverse the way you use a volt stick for
safety. That is, turn the circuit /on/ and use the volt stick to see
which red is always live and which live only when the light switch is on.

The clever bit is remembering to turn the circuit off again before
grabbing the reds to label them. But if you forget it's not always
fatal, but can be memorable.

--
Robin
reply-to address is (intended to be) valid

On Monday, 3 June 2019 10:42:00 UTC+1, Mike Clarke wrote:

The Fluke 101 could be worth considering. Joe Smith ran a series of high
voltage tests on a range of "cheap" (under 50 USD) multimeters and this
was a clear winner after testing up to 13 KV.
https://www.youtube.com/watch?v=RBkjr3b5hQo

whatever is the use in testing a multimeter to 13kV?

Officially this isn't available in the UK but can be found from
apparently reputable UK suppliers on Ebay for under £50.

It has rather limited features so might not meet everyone's needs. In
particular it does NOT measure current but this has the advantage that
there's no danger of putting it across the mains with the leads in the
'amps' socket because there isn't one.

sounds like a meter to skip.


NT

wrote in message
...
On Monday, 3 June 2019 10:42:00 UTC+1, Mike Clarke wrote:

The Fluke 101 could be worth considering. Joe Smith ran a series of high
voltage tests on a range of "cheap" (under 50 USD) multimeters and this
was a clear winner after testing up to 13 KV.
https://www.youtube.com/watch?v=RBkjr3b5hQo

whatever is the use in testing a multimeter to 13kV?

Can be handy when some fool drives into a power pole
and you end up with the 11KV line on the top of the pole
across the 240 line lower down the pole until the 11KV
breaker trips.

Officially this isn't available in the UK but can be found from
apparently reputable UK suppliers on Ebay for under £50.

It has rather limited features so might not meet everyone's needs. In
particular it does NOT measure current but this has the advantage that
there's no danger of putting it across the mains with the leads in the
'amps' socket because there isn't one.

sounds like a meter to skip.


NT

On Tue, 4 Jun 2019 05:35:53 +1000, cantankerous trolling geezer Rodent
Speed, the auto-contradicting senile sociopath, blabbered, again:


whatever is the use in testing a multimeter to 13kV?

Can be handy when some fool drives into a power pole
and you end up with the 11KV line on the top of the pole
across the 240 line lower down the pole until the 11KV
breaker trips.

Oh, shut it, you boring bull**** artist!

--
Sqwertz to Rot Speed:
"This is just a hunch, but I'm betting you're kinda an argumentative
asshole.
MID:

On Monday, 3 June 2019 20:36:08 UTC+1, Rod Speed wrote:
tabbypurr wrote in message
...
On Monday, 3 June 2019 10:42:00 UTC+1, Mike Clarke wrote:

The Fluke 101 could be worth considering. Joe Smith ran a series of high
voltage tests on a range of "cheap" (under 50 USD) multimeters and this
was a clear winner after testing up to 13 KV.
https://www.youtube.com/watch?v=RBkjr3b5hQo

whatever is the use in testing a multimeter to 13kV?

Can be handy when some fool drives into a power pole
and you end up with the 11KV line on the top of the pole
across the 240 line lower down the pole until the 11KV
breaker trips.

Lol. Lord that's clueless.

On 03/06/2019 15:28, Robin wrote:
On 03/06/2019 14:52, ss wrote:
On 03/06/2019 12:37, Jim K.. wrote:
For this application a non contact volt stick will work well
Yes I have one of those.

Rather begs the question, why do you have one? given your op...
--

Because even for something like changing a wall socket or light switch
I switch the mains off and double check with volt stick.
My safety drill far outways my electrical knowledge.

I think John meant that you can reverse the way you use a volt stick for
safety.Â* That is, turn the circuit /on/ and use the volt stick to see
which red is always live and which live only when the light switch is on.

Indeed - if you are going to test which wire is live, a non contact
method is safer and generally less hassle.




--
Cheers,

John.

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

wrote in message
...
On Monday, 3 June 2019 20:36:08 UTC+1, Rod Speed wrote:
tabbypurr wrote in message
...
On Monday, 3 June 2019 10:42:00 UTC+1, Mike Clarke wrote:

The Fluke 101 could be worth considering. Joe Smith ran a series of
high
voltage tests on a range of "cheap" (under 50 USD) multimeters and
this
was a clear winner after testing up to 13 KV.
https://www.youtube.com/watch?v=RBkjr3b5hQo

whatever is the use in testing a multimeter to 13kV?

Can be handy when some fool drives into a power pole
and you end up with the 11KV line on the top of the pole
across the 240 line lower down the pole until the 11KV
breaker trips.

Lol. Lord that's clueless.

You never could bull**** your way out of a wet paper bag.

On Wed, 5 Jun 2019 04:10:59 +1000, cantankerous trolling geezer Rodent
Speed, the auto-contradicting senile sociopath, blabbered, again:


You never could bull**** your way out of a wet paper bag.

YOU certainly KEEP bull****ting your way into your grave, you abnormal
85-year-old senile pest!

--
Sqwertz to Rot Speed:
"This is just a hunch, but I'm betting you're kinda an argumentative
asshole.
MID: