In article ,
John Rumm wrote:
One of the difficulties with many cheap chinesium meters is that they
may claim Cat II or Cat III certification, and yet even a cursory glance
inside[1] shows that to be wishful thinking.

Ages ago I bought a Maplin Gold DVM. When such things were pricey.
Normally only used for electronics, so all fairly low voltage stuff. When
it was a few years old, I measured mains with it. Large bang and clouds of
smoke. On stripping down it had arced over on the switch tracks. My guess
was copper etc dust just from wear and tear on the switch.

I now have one of those 'stick' meters sold specifically for mains testing.

--
*I get enough exercise just pushing my luck.

Dave Plowman London SW
To e-mail, change noise into sound.

On 19/07/2017 16:07, wrote:
On Wednesday, 19 July 2017 14:50:30 UTC+1, Dave Plowman (News) wrote:
In article ,
tabbypurr wrote:
On Wednesday, 19 July 2017 12:17:20 UTC+1, Dave Plowman (News) wrote:
In article ,
tabbypurr wrote:

Almost none of that's good advice either. An analogue meters takes
typically 50uA at FSD, digitals far less. No ELCB is going to give a
damn, even an RCD wouldn't either.

Avo Model 8 is typically 1mA on AC.

And my 1920s meter takes far more. Of course there are meters that aren't typical. Are you trolling?


Just trying to point out to you that a mechanical analogue meter takes
more current measuring AC than DC. So typically not 50uA on a 250v AC
range.

But if you think that trolling, carry on.

it's trolling because it has no relevance to the OP's situation, who has a DMM, and no significance to a typical analogue multimeter that takes more than 50uA but way less than 1mA on ac.

Well it was you who (unfairly in my view) criticised Harry's comment
suggesting that measurements on circuits can be more reliable if made
with a meter / device that is capable of sinking a small amount of
current in preference to a very high impedance meter.

So I see no requirement that every post in a thread need address only
the OP.



--
Cheers,

John.

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

On Tue, 18 Jul 2017 11:48:27 +0100, DerbyBorn wrote:

I got involved with someone who was wiring a external LED Floodlight into
some old wiring.

The light didn't work and from a brief tracing of the cable back to the
switch I suspect it has 2 lives.


Question:

Can I use my cheap digital meter to check between live and earth to prove
this? Could it trip an ELCB if there is one (not checked yet)

Oh how easy it is when you just use fuses. So many people grumbling about circuit breakers....

--
How do you play Iraqi bingo?
B-52...F-16...B-2

En el artículo , Huge
escribió:

https://www.youtube.com/watch?v=G2RPu4Hs_qo

ooh, mercury arc rectifiers. I'd love to see one in the flesh, working.

--
(\_/)
(='.'=) "Between two evils, I always pick
(")_(") the one I never tried before." - Mae West

En el artículo , Huge
escribió:

Hopefully from behind a thick sheet of glass. Or from a distance. Or
both.

The vids on youtube don't show much in the way of protection or warnings
(such as "do not look into laser with remaining eye")

--
(\_/)
(='.'=) "Between two evils, I always pick
(")_(") the one I never tried before." - Mae West

Mike Tomlinson wrote in
:

https://www.youtube.com/watch?v=G2RPu4Hs_qo

One at the Midland Railway Trust - Stationary Power Display - linked to a
generator.
(Derbyshire)

Mike Tomlinson wrote in
:

https://www.youtube.com/watch?v=G2RPu4Hs_qo

I once operated a machine tool which had one for the varaible speed drives.
Fascinating to watch.

Mike Tomlinson wrote in
:

https://www.youtube.com/watch?v=G2RPu4Hs_qo

Ah Castell Keys for lock-out!

En el artículo 6,
DerbyBorn escribió:

One at the Midland Railway Trust - Stationary Power Display - linked to a

Thank you, added to the list of things to go see.

--
(\_/)
(='.'=) "Between two evils, I always pick
(")_(") the one I never tried before." - Mae West

Mike Tomlinson wrote in
:

En el artículo 6,
DerbyBorn escribió:

One at the Midland Railway Trust - Stationary Power Display - linked
to a

Thank you, added to the list of things to go see.


Does this work:

https://photos.app.goo.gl/esB06wbiPGE83TV62

On Wednesday, 19 July 2017 19:18:56 UTC+1, John Rumm wrote:
On 19/07/2017 16:07, tabbypurr wrote:
On Wednesday, 19 July 2017 14:50:30 UTC+1, Dave Plowman (News) wrote:
In article ,
tabbypurr wrote:
On Wednesday, 19 July 2017 12:17:20 UTC+1, Dave Plowman (News) wrote:
In article ,
tabbypurr wrote:

Almost none of that's good advice either. An analogue meters takes
typically 50uA at FSD, digitals far less. No ELCB is going to give a
damn, even an RCD wouldn't either.

Avo Model 8 is typically 1mA on AC.

And my 1920s meter takes far more. Of course there are meters that aren't typical. Are you trolling?


Just trying to point out to you that a mechanical analogue meter takes
more current measuring AC than DC. So typically not 50uA on a 250v AC
range.

But if you think that trolling, carry on.

it's trolling because it has no relevance to the OP's situation, who has a DMM, and no significance to a typical analogue multimeter that takes more than 50uA but way less than 1mA on ac.

Well it was you who (unfairly in my view) criticised Harry's comment
suggesting that measurements on circuits can be more reliable if made
with a meter / device that is capable of sinking a small amount of
current in preference to a very high impedance meter.

that's not what I criticised


NT

On Thursday, 20 July 2017 07:01:55 UTC+1, Mike Tomlinson wrote:
En el artÃ*culo , Huge
escribió:

https://www.youtube.com/watch?v=G2RPu4Hs_qo

ooh, mercury arc rectifiers. I'd love to see one in the flesh, working.

I've worked with them. It's not reassuring to realise you're 2' from large glass bottles of hot evaporating mercury that could break & poison you to death at any moment.


NT

On 20/07/2017 14:05, wrote:
On Wednesday, 19 July 2017 19:18:56 UTC+1, John Rumm wrote:
On 19/07/2017 16:07, tabbypurr wrote:
On Wednesday, 19 July 2017 14:50:30 UTC+1, Dave Plowman (News) wrote:
In article ,
tabbypurr wrote:
On Wednesday, 19 July 2017 12:17:20 UTC+1, Dave Plowman (News) wrote:
In article ,
tabbypurr wrote:

Almost none of that's good advice either. An analogue meters takes
typically 50uA at FSD, digitals far less. No ELCB is going to give a
damn, even an RCD wouldn't either.

Avo Model 8 is typically 1mA on AC.

And my 1920s meter takes far more. Of course there are meters that aren't typical. Are you trolling?


Just trying to point out to you that a mechanical analogue meter takes
more current measuring AC than DC. So typically not 50uA on a 250v AC
range.

But if you think that trolling, carry on.

it's trolling because it has no relevance to the OP's situation, who has a DMM, and no significance to a typical analogue multimeter that takes more than 50uA but way less than 1mA on ac.

Well it was you who (unfairly in my view) criticised Harry's comment
suggesting that measurements on circuits can be more reliable if made
with a meter / device that is capable of sinking a small amount of
current in preference to a very high impedance meter.

that's not what I criticised

Well if that's so, it was not clear from your post. Harry said

"If a neutral is open circuit, it is quite possible for both L and N to
seem to be live. The only certain way to check what is what, is with
something which draws a more sensible load than a digital meter. A
test lamp or similar, might be more suitable."

and your reply was

"Almost none of that's good advice either."

How were we supposed to interpret that?


--
Cheers,

John.

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

On 20/07/2017 07:01, Mike Tomlinson wrote:
En el artículo , Huge
escribió:

https://www.youtube.com/watch?v=G2RPu4Hs_qo

ooh, mercury arc rectifiers. I'd love to see one in the flesh, working.

Not quite in the flesh, but:

https://www.youtube.com/watch?v=QY6V2syGnZA


--
Cheers,

John.

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

In article ,
wrote:
On Thursday, 20 July 2017 07:01:55 UTC+1, Mike Tomlinson wrote:
En el artículo , Huge
escribió:

https://www.youtube.com/watch?v=G2RPu4Hs_qo

ooh, mercury arc rectifiers. I'd love to see one in the flesh,
working.

I've worked with them. It's not reassuring to realise you're 2' from
large glass bottles of hot evaporating mercury that could break & poison
you to death at any moment.


I remember seeing the one at the Golder's Green Hippodrome not long after
the BBC took it over in the '60s, while the Shepherd's Bush TV Theatre was
being modernised. Very impressive looking device.

Think it was only retained to provide 110DC for the Mole camera crane.
Don't think much in the way of TV lighting used that, although the back
projection systems might have too.

--
*Keep honking...I'm reloading.

Dave Plowman London SW
To e-mail, change noise into sound.

On Thursday, 20 July 2017 14:17:44 UTC+1, John Rumm wrote:
On 20/07/2017 14:05, tabbypurr wrote:
On Wednesday, 19 July 2017 19:18:56 UTC+1, John Rumm wrote:
On 19/07/2017 16:07, tabbypurr wrote:
On Wednesday, 19 July 2017 14:50:30 UTC+1, Dave Plowman (News) wrote:
In article ,
tabbypurr wrote:
On Wednesday, 19 July 2017 12:17:20 UTC+1, Dave Plowman (News) wrote:
In article ,
tabbypurr wrote:

Almost none of that's good advice either. An analogue meters takes
typically 50uA at FSD, digitals far less. No ELCB is going to give a
damn, even an RCD wouldn't either.

Avo Model 8 is typically 1mA on AC.

And my 1920s meter takes far more. Of course there are meters that aren't typical. Are you trolling?


Just trying to point out to you that a mechanical analogue meter takes
more current measuring AC than DC. So typically not 50uA on a 250v AC
range.

But if you think that trolling, carry on.

it's trolling because it has no relevance to the OP's situation, who has a DMM, and no significance to a typical analogue multimeter that takes more than 50uA but way less than 1mA on ac.

Well it was you who (unfairly in my view) criticised Harry's comment
suggesting that measurements on circuits can be more reliable if made
with a meter / device that is capable of sinking a small amount of
current in preference to a very high impedance meter.

that's not what I criticised

Well if that's so, it was not clear from your post. Harry said

"If a neutral is open circuit, it is quite possible for both L and N to
seem to be live. The only certain way to check what is what, is with
something which draws a more sensible load than a digital meter. A
test lamp or similar, might be more suitable."

and your reply was

"Almost none of that's good advice either."

How were we supposed to interpret that?

IIRC he said more than that, and almost none of it was good advice. Obviously advice to not use extremely high impedance meter is reasonable, the rest was bad. Do we really need to state the bleeding obvious?


NT

On Thursday, 20 July 2017 14:26:55 UTC+1, Dave Plowman (News) wrote:
In article ,
tabbypurr wrote:
On Thursday, 20 July 2017 07:01:55 UTC+1, Mike Tomlinson wrote:
En el artÃ*culo , Huge
escribió:

https://www.youtube.com/watch?v=G2RPu4Hs_qo

ooh, mercury arc rectifiers. I'd love to see one in the flesh,
working.

I've worked with them. It's not reassuring to realise you're 2' from
large glass bottles of hot evaporating mercury that could break & poison
you to death at any moment.


I remember seeing the one at the Golder's Green Hippodrome not long after
the BBC took it over in the '60s, while the Shepherd's Bush TV Theatre was
being modernised. Very impressive looking device.

Think it was only retained to provide 110DC for the Mole camera crane.
Don't think much in the way of TV lighting used that, although the back
projection systems might have too.

The ones I worked with supplied arc-light projectors. The place was straight out of history.


NT

On 20/07/2017 07:01, Mike Tomlinson wrote:
En el artículo , Huge
escribió:

https://www.youtube.com/watch?v=G2RPu4Hs_qo

ooh, mercury arc rectifiers. I'd love to see one in the flesh, working.


The Museum of Power in the Cardigan Bay area

On 20/07/2017 07:01, Mike Tomlinson wrote:
En el artículo , Huge
escribió:

https://www.youtube.com/watch?v=G2RPu4Hs_qo

ooh, mercury arc rectifiers. I'd love to see one in the flesh, working.



oops - additional information!

It is The Internal Fire Museum of Power. http://www.internalfire.com/

A very wortwhile place to visit.

En el artículo ,
DerbyBorn escribió:

Does this work:

https://photos.app.goo.gl/esB06wbiPGE83TV62

Yes. Thanks again.

There's something rather alien about these things. The bulbous head and
the phase 'tentacles'.

I'd love to see one working before they all become a curiosity.

--
(\_/)
(='.'=) "Between two evils, I always pick
(")_(") the one I never tried before." - Mae West

En el artículo , John
Rumm escribió:

Not quite in the flesh, but:

https://www.youtube.com/watch?v=QY6V2syGnZA

I've seen that, thanks, and many others on YewTewb. But something in me
wants to see a real live working one and to savour the unshielded
ultraviolet radiation.

I suppose it comes from being old enough to remember valve TVs - there
was that particular smell of hot valves, ozone, warm dust, hot
bakelite/paxolin, overheated resistors, voltage droppers that you get
from vintage valve radios and TVs.

I'm pretty sure those of a certain age reading this will be nodding in
agreement.

--
(\_/)
(='.'=) "Between two evils, I always pick
(")_(") the one I never tried before." - Mae West

En el artículo , Sam
escribió:

The Museum of Power in the Cardigan Bay area

Thanks, that is on my bucket list.

The Power Hall at MOSI (Museum of Science and Industry) in Manc is also
good. Wonderful working steam engines and turbines. I left too little
time to go look at the rest of the exhibition.

--
(\_/)
(='.'=) "Between two evils, I always pick
(")_(") the one I never tried before." - Mae West

En el artículo , Sam
escribió:

It is The Internal Fire Museum of Power. http://www.internalfire.com/
A very wortwhile place to visit.

Thanks again. Bookmarked. May combine that with a few days in Swansea,
never been down that way and believe it's well worth a visit.

--
(\_/)
(='.'=) "Between two evils, I always pick
(")_(") the one I never tried before." - Mae West

On Thursday, 20 July 2017 19:06:18 UTC+1, Mike Tomlinson wrote:
En el artÃ*culo , John
Rumm escribió:

Not quite in the flesh, but:

https://www.youtube.com/watch?v=QY6V2syGnZA

I've seen that, thanks, and many others on YewTewb. But something in me
wants to see a real live working one and to savour the unshielded
ultraviolet radiation.

I suppose it comes from being old enough to remember valve TVs - there
was that particular smell of hot valves, ozone, warm dust, hot
bakelite/paxolin, overheated resistors, voltage droppers that you get
from vintage valve radios and TVs.

I'm pretty sure those of a certain age reading this will be nodding in
agreement.

I remember the cooking dust and slow baking plastic smells, and ozone if arcing.

Mercury rectifiers don't smell, they're just a bit like having a nicely polished hand grenade in the room. They should never go wrong. But you know they could.


NT

On Wed, 19 Jul 2017 15:43:52 +0100, John Rumm
wrote:

On 19/07/2017 10:41, T i m wrote:
On Tue, 18 Jul 2017 22:37:30 -0000 (UTC), Cursitor Doom

and such a meter is *not* safe to carry out mains
measurements with.

But I have done so (many times) and yet somehow I'm still here

I am sure you are well aware of the spectacular holes in that bit of
logic.

I do indeed. However, I *am* still here. ;-)

So far I have never been hit by a car while I am crossing a road.

I have so I couldn't use that one. ;-)

It does not mean that it can't happen or is necessarily that rare an event.

Don't I know it. ;-)

That said, 'of course' there is a minimum design / build spec that
most who know what they are doing would consider ideal / acceptable
(and ironically makes them potentially safer for novice use).

to be rated for (usually 3 or 4 at a specified voltage).

To be *formally* rated for such voltages.

One of the difficulties with many cheap chinesium meters is that they
may claim Cat II or Cat III certification, and yet even a cursory glance
inside[1] shows that to be wishful thinking.

Ok.

Now chances are you will be able to measure voltages inside your CU with
one of those many times and get away with it.

Or any other 240V 'thing' etc ...

The problem comes when you
don't because there was a 1kV transient at just the wrong moment.

Or there was a car after all ... or the gas bottle you used for the
compressor expansion was weakened somehow or the time you forgot you
put your safety glasses or gloves on etc etc. ;-(

the further you move from a CU - out to the far reaches of a circuit or
in fact into an appliance, then generally the lower the risk.

Which is where I thought we were in this case?


[1] Inadequate conductive path separation, lack of low to high voltage
isolation, no HRC fusing, no spark gaps, no input protection MOVs etc.

What would you expect for £2.99. ;-)

Cheers, T i m

On Thursday, 20 July 2017 20:29:54 UTC+1, T i m wrote:
On Wed, 19 Jul 2017 15:43:52 +0100, John Rumm
wrote:
On 19/07/2017 10:41, T i m wrote:
On Tue, 18 Jul 2017 22:37:30 -0000 (UTC), Cursitor Doom

and such a meter is *not* safe to carry out mains
measurements with.

What would you expect for £2.99. ;-)

damn, you got stung!

Personally I don't mind using such meters after a low value mains fuse eg 5A lighting circuit. If things go wrong it will destroy the meter, not you.
But inside the CU? Not with a China special.


NT

Mike Tomlinson wrote in news:GYoySJD5$OcZFw+1
@jasper.org.uk:

https://photos.app.goo.gl/esB06wbiPGE83TV62

Hope you go:

On Wed, 19 Jul 2017 15:27:19 -0000 (UTC), Cursitor Doom
wrote:

On Wed, 19 Jul 2017 10:41:15 +0100, T i m wrote:

But I have done so (many times) and yet somehow I'm still here

More's the pity.

On the positive side I'm living rent free in your head (troll) and
that makes me happy. ;-)

Why don't you stick your tongue in a 13A outlet and do
us all a favour?

I did (effectively), as a kid, when using my teeth to strip the
insulation off the two ends of some broken xmyth tree lights ... and
yet somehow I'm still here?

Anyway, I'll have to check the current legal status of 'incitement to
commit suicide' ... (so thanks for that).

Cheers, T i m

On Thu, 20 Jul 2017 15:21:09 -0700 (PDT), wrote:

On Thursday, 20 July 2017 20:29:54 UTC+1, T i m wrote:
On Wed, 19 Jul 2017 15:43:52 +0100, John Rumm
wrote:
On 19/07/2017 10:41, T i m wrote:
On Tue, 18 Jul 2017 22:37:30 -0000 (UTC), Cursitor Doom

and such a meter is *not* safe to carry out mains
measurements with.

What would you expect for £2.99. ;-)

damn, you got stung!

Personally I don't mind using such meters after a low value mains fuse eg 5A lighting circuit. If things go wrong it will destroy the meter, not you.

I wouldn't use one if I had something 'better' to hand, if only
because the leads are often not particularly nice.

But inside the CU? Not with a China special.

I can't see how likely it would be to need to use one inside a CU (not
that anyone was talking about doing such specifically) but if you had
lost all power, it was late / dark / cold and had nothing else ...

Cheers, T i m

Sam laid this down on his screen :
On 20/07/2017 07:01, Mike Tomlinson wrote:
En el artículo , Huge
escribió:

https://www.youtube.com/watch?v=G2RPu4Hs_qo

ooh, mercury arc rectifiers. I'd love to see one in the flesh, working.


The Museum of Power in the Cardigan Bay area

Museum of Internal Fire - https://www.internalfire.com/

Just to the north of Cardigan. Well worth a visit, mention my name to
the guy who runs it, if you ever get there.

On 21/07/2017 08:06, T i m wrote:
On Thu, 20 Jul 2017 15:21:09 -0700 (PDT), wrote:

On Thursday, 20 July 2017 20:29:54 UTC+1, T i m wrote:
On Wed, 19 Jul 2017 15:43:52 +0100, John Rumm
wrote:
On 19/07/2017 10:41, T i m wrote:
On Tue, 18 Jul 2017 22:37:30 -0000 (UTC), Cursitor Doom

and such a meter is *not* safe to carry out mains
measurements with.

What would you expect for £2.99. ;-)

damn, you got stung!

Personally I don't mind using such meters after a low value mains
fuse eg 5A lighting circuit. If things go wrong it will destroy the
meter, not you.

I wouldn't use one if I had something 'better' to hand, if only
because the leads are often not particularly nice.

But inside the CU? Not with a China special.

I can't see how likely it would be to need to use one inside a CU
(not that anyone was talking about doing such specifically) but if
you had lost all power, it was late / dark / cold and had nothing
else ...

This subject comes up from time to time, and always seems to end up in a
discussion that goes around in circles for one reason or another.
Usually because someone will caution that there are risks associated
with dealing with higher energy electrical feeds and that some test gear
is better able to mitigate those risks than others. Someone else then
normally then get all anecdotal and reminds us they have managed with a
£2.49 meter from the market stall for the last 4 decades and their
grandfather before them and never had a problem.

The reality is that for lots of DIY activities, the cheap meter will be
adequate - you are probably not interested in high accuracy, and it will
beep nicely while buzzing out that USB lead or appliance flex. If you
are into electronics or computing or appliance repair etc then you will
find it invaluable for all kinds of things.

The pro electrician will carry pro level gear plus have a much more
nuanced knowledge of what situations pose more risk. They are also far
more likely to be making measurements on live installations in more
risky situations.

The difficulty comes when those two worlds mix. Say for example someone
decides they need to test if a socket is live, so they defeat the
shutters on it and poke their test leads into the socket. Usually this
will be safe enough. However there may be a problem like they forgot
they had the meter still set to an ohms range, or set on a current
measurement range (or they are on the right range but unlucky enough to
pick the moment there is a big transient spike on the supply).

What happens next will then be determined by a bunch of factors outside
the users control that range from the meter indicating an error on the
display, to it blowing an internal fuse, to going pop, to going bang, to
going bang and catching fire, to exploding, to exploding and showering
those nearby with flying bits of meter and some molten test leads and
bits of copper, to doing all that and causing an arc flash explosion a
the socket, to - well worse - you get the picture.

It might be you live in a place where you are very close to a sub
station and have a very low supply impedance. It might be that the
prospective fault current in your CU, and for that matter, at any socket
or light fitting relatively near to it, will have a prospective fault
current that is high enough for these bad things to happen. It might be
so high that it even exceeds the breaking capacity of the circuit
breakers in the CU itself, meaning that in the worst case you are
relying on the incomer main fuse for ultimate fault protection. On a
supply rated at ~24kW nominal continuous (and probably ten times that
under fault conditions) you can probably see there is potential for
things to get out of hand quickly.

So how does one advice on a choice of meter? Its difficult without being
cautious and including relevant warnings to the prospective user -
especially if you don't know if they are the type likely to know what a
prospective short circuit current is, or know what it actually measures
in their house, or which accessories are within very low ohms range of
the consumer unit.


--
Cheers,

John.

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

Mike Tomlinson wrote in
:

En el artículo , John
Rumm escribió:

Not quite in the flesh, but:

https://www.youtube.com/watch?v=QY6V2syGnZA

I've seen that, thanks, and many others on YewTewb. But something in me
wants to see a real live working one and to savour the unshielded
ultraviolet radiation.

I suppose it comes from being old enough to remember valve TVs - there
was that particular smell of hot valves, ozone, warm dust, hot
bakelite/paxolin, overheated resistors, voltage droppers that you get
from vintage valve radios and TVs.

I'm pretty sure those of a certain age reading this will be nodding in
agreement.


https://photos.app.goo.gl/XpRoUthUL5wX5GqL2

Part of a battery charging system from 1958

On Fri, 21 Jul 2017 16:12:37 +0100, John Rumm
wrote:

snip wise words for brevity

So how does one advice on a choice of meter?

... and for whom? If I told my BIL he needed to spend even 20 quid on
a meter that he might use a couple of times to check a battery or a
fuse ... before forgetting where he put it or finding it 'dead' (flat
battery) I know he's going to say 'no thanks'.

If I gave him a DMM I bought 5 of for £1.99 each (+ a PP3) he would
probably (not) use that either, especially anywhere near anything
mains voltage.

However, if I'm ever over there and they ask me to test / fix
something, at least I will have *something* to work with and that
might be safer than some other test I might try to rig up instead. ;-)

Its difficult without being
cautious and including relevant warnings to the prospective user -
especially if you don't know if they are the type likely to know what a
prospective short circuit current is, or know what it actually measures
in their house, or which accessories are within very low ohms range of
the consumer unit.

Of course, but I'm not sure anything I say (for example) would have
any impact on that ... and as they say, 'buyer beware'.

The problem is, even a 'good' meter in the wrong hands could be a
liability (to that user ... and using your usage of 'poking about in a
CU'), as could a screwdriver ... or a finger. ;-(

So, for the record, I'm not and never have *recommended* the use of
any sub-par test equipment under any circumstances to anyone. What I
would like though is every house to own a DMM, a foot pump, battery
charger, a reasonable range of tools etc etc so that when I happen
round there and find myself having to fix something for them, I've got
something more than my Leatherman PST II to use. ;-)

Cheers, T i m

On 21/07/2017 18:29, T i m wrote:
What I
would like though is every house to own a DMM, a foot pump, battery
charger, a reasonable range of tools etc etc so that when I happen
round there and find myself having to fix something for them, I've got
something more than my Leatherman PST II to use.;-)

But the problem is that, because they don't use the tools, they get
relegated to somewhere in the back of a damp shed and get rusted up to
the point of being next to useless by the time they need you to use them.

--
Mike Clarke

En el artículo , Harry Bloomfield harry.m1b
escribió:

Museum of Internal Fire - https://www.internalfire.com/

Just to the north of Cardigan. Well worth a visit, mention my name to
the guy who runs it, if you ever get there.

Many thanks. Added to the list

--
(\_/)
(='.'=) "Between two evils, I always pick
(")_(") the one I never tried before." - Mae West

On 21/07/2017 16:12, John Rumm wrote:
8


So how does one advice on a choice of meter? Its difficult without being
cautious and including relevant warnings to the prospective user -
especially if you don't know if they are the type likely to know what a
prospective short circuit current is, or know what it actually measures
in their house, or which accessories are within very low ohms range of
the consumer unit.



Well the obvious thing is to have two meters, one that only does volts
and one a clamp on for current.
Its pretty safe then.

Of course there isn't really much need to poke about in a live CU.

En el artículo , Mike Clarke
escribió:

But the problem is that, because they don't use the tools, they get
relegated to somewhere in the back of a damp shed and get rusted up to
the point of being next to useless by the time they need you to use them.

Either that or they're cheap **** - e.g. screwdrivers made of cheese -
which is useless.

--
(\_/)
(='.'=) "Between two evils, I always pick
(")_(") the one I never tried before." - Mae West

On Fri, 21 Jul 2017 20:28:39 +0100, Mike Clarke
wrote:

On 21/07/2017 18:29, T i m wrote:
What I
would like though is every house to own a DMM, a foot pump, battery
charger, a reasonable range of tools etc etc so that when I happen
round there and find myself having to fix something for them, I've got
something more than my Leatherman PST II to use.;-)

But the problem is that, because they don't use the tools, they get
relegated to somewhere in the back of a damp shed and get rusted up to
the point of being next to useless by the time they need you to use them.

True. ;-(

Before I married Mrs Tim Mk2 (and had kids) I kept and used my Myford
ML10 lathe, bandsaw and pillar drill etc in (what others would have
called) the middle bedroom, where it all stayed nice and warm and dry.

Now they are in the workshop, I have to make sure I keep the lathe
covered in the winter to (as you reference), stop it going rusty.

On the other hand, the kids wouldn't have gone rusty in the
workshop//////// annexe building ... ;-(

Cheers, T i m

On Fri, 21 Jul 2017 16:12:37 +0100, John Rumm wrote:

So how does one advice on a choice of meter? Its difficult without being
cautious and including relevant warnings to the prospective user -
especially if you don't know if they are the type likely to know what a
prospective short circuit current is, or know what it actually measures
in their house, or which accessories are within very low ohms range of
the consumer unit.

The other issue is that *possession* of one of these alone, even if you
know what its limitations are and use it appropriately, can still cost
you dearly. One of your teenage kids may pick it up one day, see it's
rated for 250V and stick it in the mains right at wrong moment. I'd
sooner have no meter at all if I had kids around.



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On 18/07/2017 12:47, Martin Brown wrote:
o consider the possibility that your leads are less than perfect.

I prefer a good old mains testing neon screwdriver (even though they are
frowned upon these days). If the neon glows it ain't safe to touch.


The problem is the failure mode ... if neon blows a user can assume no
glow = safe

But I do have some more than 40 years old still working - so pretty
reliable.

For most things I use a Digital Multimeter or a Martindale Tester (I
know this is neon - but lots of them)