Hi all,

Back in my day when we wanted to test household cable insulation we got out a Megger and cranked its little handle up to 500V to check for leaks. But they don't seem to make these nifty little gadgets any more.
Anyway, I guess they were a bit limited in some respects to be honest.
So what's the thing to go for nowadays for the serious DIYer? Be nice to have some functionality for testing how good an Earth is and such like similar stuff 'n all. Any suggestions which won't break the bank? I want quality gear but don't want to pay for it. Preferably.

cheers.

On Sun, 4 Aug 2013 15:00:48 -0700 (PDT),
wrote:

Hi all,

Back in my day when we wanted to test household cable insulation we got out a Megger and cranked its little handle up to 500V to check for leaks. But they don't seem to make these nifty little gadgets any more.
Anyway, I guess they were a bit limited in some respects to be honest.
So what's the thing to go for nowadays for the serious DIYer? Be nice to have some functionality for testing how good an Earth is and such like similar stuff 'n all. Any suggestions which won't break the bank? I want quality gear but don't want to pay for it. Preferably.

cheers.

What do you want to do?

I bought a £19-00 DMM from Wickes that will test earth bonding, and
could easily test leakage through insulation if I needed the facility.

You could go out and buy a mutifunction tester for a couple of
hundred, but if you know the parameters you want to measure then
producing the correct test Voltage and currents shouldn't be too
difficult.

My wickes meter is a little out on the 0 to 20mA range (around 5% of
the value read), but apart from this I couldn't complain. It's been
soaked and Zapped with mains when left set to mA more than once. Apart
from a few fuses it still chugs on.

A cheapo meter is more than adequate for my work, but I only work on
my own property and I know exactly where the feeds come from and what
they pass through protection wise.

I never actually got around to any high Voltage testing, for the
simple reason that after wiring with new cable and components there
seemed little point. In fact the most likely cause of such leakage
would be water on an old installation and by the time the stuff had
trickled into a JB it would probably show up on the Ohms range anyway.
AB

On Sunday, 4 August 2013 23:00:48 UTC+1, wrote:
Hi all,



Back in my day when we wanted to test household cable insulation we got out a Megger

I bought a UNI-T electrical tester, and didn't expect too much from an unknown brand. I was pleasantly surprised by their quality, and it's done everything I want of it.

http://www.uni-trend.com/UT526.html

Bought mine through an ebay supplier:

http://www.ebay.co.uk/sch/i.html?_tr...at=0&_from=R40

It's not Fluke/Megger/Other-tap-brand, and if I was doing work on a commercial basis I would certainly want something with a calibration certificate.

However for checking cables are undamaged after plasterboarding etc, I'd recommend it.

On Mon, 05 Aug 2013 02:09:28 -0700, wrote:

On Sunday, 4 August 2013 23:00:48 UTC+1, wrote:

Back in my day when we wanted to test household cable insulation we got
out a Megger

I bought a UNI-T electrical tester, and didn't expect too much from an
unknown brand. I was pleasantly surprised by their quality, and it's
done everything I want of it.

http://www.uni-trend.com/UT526.html

I got this one:

http://www.tlc-direct.co.uk/Main_Ind...Test_Meters_2/
index.html



--
Use the BIG mirror service in the UK: http://www.mirrorservice.org
My posts (including this one) are my copyright and if @diy_forums on
Twitter wish to tweet them they can pay me £30 a post
*lightning surge protection* - a w_tom conductor

On Sun, 4 Aug 2013 15:00:48 -0700 (PDT), wrote:

I want quality gear but don't want to pay for it.

Find a thick electrical apprentice, get an accomplice to distract him with a
mobile phone, a picture of tits, or idle talk about the x factor. Permanently
borrow the test gear he was supposed to be looking after.

Maybe see report of another apprentice getting bollocked in here.

--

In article ,
wrote:
Hi all,

Back in my day when we wanted to test household cable insulation we got
out a Megger and cranked its little handle up to 500V to check for
leaks. But they don't seem to make these nifty little gadgets any more.


They do, but not hand cranked. Electronics now.

Anyway, I guess they were a bit limited in some respects to be honest.
So what's the thing to go for nowadays for the serious DIYer? Be nice to
have some functionality for testing how good an Earth is and such like
similar stuff 'n all. Any suggestions which won't break the bank? I want
quality gear but don't want to pay for it. Preferably.

Depends what you want to do. If you want to check an actual earth
correctly, you'll need the correct unit which isn't cheap. Same for
insulation. They cost so much it would probably be cheaper getting a pro
in.

If you just need a general purpose DVM, prices start from a couple of
quid. 30 or so will buy a decent enough quality one.

--
*A person who smiles in the face of adversity probably has a scapegoat *

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

On 04/08/2013 23:00, wrote:
Hi all,

Back in my day when we wanted to test household cable insulation we
got out a Megger and cranked its little handle up to 500V to check
for leaks. But they don't seem to make these nifty little gadgets any
more.

ebay ;-)

(or £50 will get you a decent second hand battery driven equal of what
you had before with the Megger name on it)

Anyway, I guess they were a bit limited in some respects to
be honest. So what's the thing to go for nowadays for the serious
DIYer? Be nice to have some functionality for testing how good an
Earth is and such like similar stuff 'n all. Any suggestions which
won't break the bank? I want quality gear but don't want to pay for
it. Preferably.


Well you have a few options...

Basically you need "proper"[1] test equipment designed for the job, and
not a multimeter. This could either be up to three separate boxes
(Insulation resistance and continuity tester, Earth Loop Tester, and RCD
Tester) or an integrated box of tricks with all the features in one box.

Separate boxes - usually to 16th edition standard (i.e. Earth loop
tester may lack a "no trip" test capability), are often around the £50
each for decent branded kit (Megger, Robin etc)

Integrated boxes can be had new for mid 300s normally. Dialog do quite a
neat one.



[1] This is one of those occasions (where you may be routinely making
connections to live circuits) where you *must* get something that is
properly designed to do the job safely - that means decent input
protection, arc protection, and a HRC fuse and not a piddly little 20mm
glass one. There is some cheap kit on ebay, but I would be wary until
you have seen exactly how its constructed.





--
Cheers,

John.

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

On 05/08/2013 12:25, Dave Plowman (News) wrote:

If you just need a general purpose DVM, prices start from a couple of
quid. 30 or so will buy a decent enough quality one.

A nice description of why you never want to go poking about in a CU with
a cheap meter:

http://www.myflukestore.com/crm_uplo...ation_note.pdf

or

http://preview.tinyurl.com/np96f4m

--
Cheers,

John.

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

On 04/08/2013 23:00, wrote:
Hi all,

Back in my day when we wanted to test household cable insulation we got out a Megger and cranked its little handle up to 500V to check for leaks. But they don't seem to make these nifty little gadgets any more.
Anyway, I guess they were a bit limited in some respects to be honest.
So what's the thing to go for nowadays for the serious DIYer? Be nice to have some functionality for testing how good an Earth is and such like similar stuff 'n all. Any suggestions which won't break the bank? I want quality gear but don't want to pay for it. Preferably.

cheers.

I have a ROBIN KMP 3050DL fully software driven, does all you need
.... can pick them up on ebay for good deals.

In article ,
John Rumm wrote:
On 05/08/2013 12:25, Dave Plowman (News) wrote:

If you just need a general purpose DVM, prices start from a couple of
quid. 30 or so will buy a decent enough quality one.

A nice description of why you never want to go poking about in a CU with
a cheap meter:

http://www.myflukestore.com/crm_uplo...ation_note.pdf

or

http://preview.tinyurl.com/np96f4m

My non too cheap Maplin Gold went bang on mains. And it was correctly set
for 240v AC. What appeared to have happened was brass dust from the switch
tracks causing it to arc over - after many years of use. But pretty well
never on mains.

So I now only use a proper dedicated mains tester. One of these:-


http://www.tlc-direct.co.uk/Main_Ind...741/index.html

I no longer trust the normal rotary switch type DVM at high voltage. Even
my Fluke.

--
*Welcome to **** Creek - sorry, we're out of paddles*

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

On Mon, 05 Aug 2013 13:28:16 +0100, Rick Hughes wrote:

On 04/08/2013 23:00, wrote:
Hi all,

Back in my day when we wanted to test household cable insulation we got
out a Megger and cranked its little handle up to 500V to check for
leaks. But they don't seem to make these nifty little gadgets any more.

Anyway, I guess they were a bit limited in some respects to be honest.
So what's the thing to go for nowadays for the serious DIYer? Be nice
to have some functionality for testing how good an Earth is and such
like similar stuff 'n all. Any suggestions which won't break the bank?
I want quality gear but don't want to pay for it. Preferably.

cheers.

I have a ROBIN KMP 3050DL fully software driven, does all you need
... can pick them up on ebay for good deals.

Yup, I got one of those when I did the rewire too.

--
Use the BIG mirror service in the UK: http://www.mirrorservice.org
My posts (including this one) are my copyright and if @diy_forums on
Twitter wish to tweet them they can pay me £30 a post
*lightning surge protection* - a w_tom conductor

On Mon, 05 Aug 2013 13:18:43 +0100, John Rumm wrote:

On 05/08/2013 12:25, Dave Plowman (News) wrote:

If you just need a general purpose DVM, prices start from a couple of
quid. 30 or so will buy a decent enough quality one.

A nice description of why you never want to go poking about in a CU with
a cheap meter:

http://www.myflukestore.com/crm_uplo..._multimeters_-
_abcs_of_multimeter_safety_multimeter_safety_and_y ou_application_note.pdf

or

http://preview.tinyurl.com/np96f4m

And then there was:

http://ecmweb.com/arc-flash/case-deadly-arc-flash



--
Use the BIG mirror service in the UK: http://www.mirrorservice.org
My posts (including this one) are my copyright and if @diy_forums on
Twitter wish to tweet them they can pay me £30 a post
*lightning surge protection* - a w_tom conductor

On 05/08/2013 14:25, Dave Plowman (News) wrote:
In article ,
John Rumm wrote:
On 05/08/2013 12:25, Dave Plowman (News) wrote:

If you just need a general purpose DVM, prices start from a couple of
quid. 30 or so will buy a decent enough quality one.

A nice description of why you never want to go poking about in a CU with
a cheap meter:

http://www.myflukestore.com/crm_uplo...ation_note.pdf

or

http://preview.tinyurl.com/np96f4m

My non too cheap Maplin Gold went bang on mains. And it was correctly set
for 240v AC. What appeared to have happened was brass dust from the switch
tracks causing it to arc over - after many years of use. But pretty well
never on mains.

So I now only use a proper dedicated mains tester. One of these:-


http://www.tlc-direct.co.uk/Main_Ind...741/index.html

I no longer trust the normal rotary switch type DVM at high voltage. Even
my Fluke.

All the flukes I have seen the inside of, had proper input protection -
probe sockets in shuttered off bits of case work, air gaps in the PCB,
MOVs a plenty, and proper HRC fusing. A far cry from my Maplin
"Precision Gold" jobbie.


--
Cheers,

John.

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

On Monday, 5 August 2013 18:17:53 UTC+2, John Rumm wrote:
On 05/08/2013 14:25, Dave Plowman (News) wrote:

In article ,

John Rumm wrote:

On 05/08/2013 12:25, Dave Plowman (News) wrote:



If you just need a general purpose DVM, prices start from a couple of

quid. 30 or so will buy a decent enough quality one.



A nice description of why you never want to go poking about in a CU with

a cheap meter:



http://www.myflukestore.com/crm_uplo...ation_note.pdf



or



http://preview.tinyurl.com/np96f4m



My non too cheap Maplin Gold went bang on mains. And it was correctly set

for 240v AC. What appeared to have happened was brass dust from the switch

tracks causing it to arc over - after many years of use. But pretty well

never on mains.



So I now only use a proper dedicated mains tester. One of these:-





http://www.tlc-direct.co.uk/Main_Ind...741/index.html



I no longer trust the normal rotary switch type DVM at high voltage. Even

my Fluke.



All the flukes I have seen the inside of, had proper input protection -

probe sockets in shuttered off bits of case work, air gaps in the PCB,

MOVs a plenty, and proper HRC fusing. A far cry from my Maplin

"Precision Gold" jobbie.


That's the same one as mine that's just packed up: Maplin White Gold/Precision Gold model WG020. Had a good innings; really can't remember exactly when I bought it but it must have been well over 20 years ago. I've been having to use a cheap backup Draper pocket analogue multimeter instead. It claims to be good for measuring up to 500V, but if I want to measure mains levels with it I hold both probes with one hand so if the insulation goes tits up, I may get a belt but at least the current wont flow across my chest!

On 05/08/2013 19:00, wrote:

That's the same one as mine that's just packed up: Maplin White
Gold/Precision Gold model WG020. Had a good innings; really can't
remember exactly when I bought it but it must have been well over 20

Mine is a M125 - probably also 20 years old. As a general purpose meter
its not bad, but I keep it way from anything "high energy"

years ago. I've been having to use a cheap backup Draper pocket
analogue multimeter instead. It claims to be good for measuring up to
500V, but if I want to measure mains levels with it I hold both
probes with one hand so if the insulation goes tits up, I may get a
belt but at least the current wont flow across my chest!

As the links illustrate, if an arc flash gets you, shock is the least of
your worries!


--
Cheers,

John.

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

On Mon, 05 Aug 2013 19:25:13 +0100, John Rumm
wrote:

On 05/08/2013 19:00, wrote:

That's the same one as mine that's just packed up: Maplin White
Gold/Precision Gold model WG020. Had a good innings; really can't
remember exactly when I bought it but it must have been well over 20

Mine is a M125 - probably also 20 years old. As a general purpose meter
its not bad, but I keep it way from anything "high energy"

years ago. I've been having to use a cheap backup Draper pocket
analogue multimeter instead. It claims to be good for measuring up to
500V, but if I want to measure mains levels with it I hold both
probes with one hand so if the insulation goes tits up, I may get a
belt but at least the current wont flow across my chest!

As the links illustrate, if an arc flash gets you, shock is the least of
your worries!

Can't find a link but there are some stills around online with the result of a
multimeter explosion. Cheap meters should be binned or confined to use on low
voltage dc on the bench.

Interesting video of the indestructability of Flukes.... if you can stand the
accent!

http://www.youtube.com/watch?v=qlA7-fh5nDQ


--

On Mon, 05 Aug 2013 14:25:28 +0100, "Dave Plowman (News)"
wrote:

In article ,
John Rumm wrote:
On 05/08/2013 12:25, Dave Plowman (News) wrote:

If you just need a general purpose DVM, prices start from a couple of
quid. 30 or so will buy a decent enough quality one.

A nice description of why you never want to go poking about in a CU with
a cheap meter:

http://www.myflukestore.com/crm_uplo...ation_note.pdf

or

http://preview.tinyurl.com/np96f4m

My non too cheap Maplin Gold went bang on mains. And it was correctly set
for 240v AC. What appeared to have happened was brass dust from the switch
tracks causing it to arc over - after many years of use. But pretty well
never on mains.

So I now only use a proper dedicated mains tester. One of these:-


http://www.tlc-direct.co.uk/Main_Ind...741/index.html

I no longer trust the normal rotary switch type DVM at high voltage. Even
my Fluke.

There is no cause to be concerned with the engineering of Fluke meters.

Use fused leads if you are paranoid.


--

In article , The Other Mike
scribeth thus
On Mon, 05 Aug 2013 19:25:13 +0100, John Rumm
wrote:

On 05/08/2013 19:00, wrote:

That's the same one as mine that's just packed up: Maplin White
Gold/Precision Gold model WG020. Had a good innings; really can't
remember exactly when I bought it but it must have been well over 20

Mine is a M125 - probably also 20 years old. As a general purpose meter
its not bad, but I keep it way from anything "high energy"

years ago. I've been having to use a cheap backup Draper pocket
analogue multimeter instead. It claims to be good for measuring up to
500V, but if I want to measure mains levels with it I hold both
probes with one hand so if the insulation goes tits up, I may get a
belt but at least the current wont flow across my chest!

As the links illustrate, if an arc flash gets you, shock is the least of
your worries!

Can't find a link but there are some stills around online with the result of a
multimeter explosion. Cheap meters should be binned or confined to use on low
voltage dc on the bench.

Interesting video of the indestructability of Flukes.... if you can stand the
accent!

http://www.youtube.com/watch?v=qlA7-fh5nDQ



Bizarre!.. Still I'd not using anything less than one of they for high
power field work..
--
Tony Sayer

Anyone heard of this outfit? They have a peruseworthy range of meters. What does this erudite panel think of their wares?

http://testinstrumentsolutions.co.uk/

On Mon, 05 Aug 2013 12:56:12 +0100, John Rumm
wrote:

On 04/08/2013 23:00, wrote:
Hi all,

Back in my day when we wanted to test household cable insulation we
got out a Megger and cranked its little handle up to 500V to check
for leaks. But they don't seem to make these nifty little gadgets any
more.

ebay ;-)

(or £50 will get you a decent second hand battery driven equal of what
you had before with the Megger name on it)

Anyway, I guess they were a bit limited in some respects to
be honest. So what's the thing to go for nowadays for the serious
DIYer? Be nice to have some functionality for testing how good an
Earth is and such like similar stuff 'n all. Any suggestions which
won't break the bank? I want quality gear but don't want to pay for
it. Preferably.


Well you have a few options...

Basically you need "proper"[1] test equipment designed for the job, and
not a multimeter. This could either be up to three separate boxes
(Insulation resistance and continuity tester, Earth Loop Tester, and RCD
Tester) or an integrated box of tricks with all the features in one box.

Separate boxes - usually to 16th edition standard (i.e. Earth loop
tester may lack a "no trip" test capability), are often around the £50
each for decent branded kit (Megger, Robin etc)

Integrated boxes can be had new for mid 300s normally. Dialog do quite a
neat one.



[1] This is one of those occasions (where you may be routinely making
connections to live circuits) where you *must* get something that is
properly designed to do the job safely - that means decent input
protection, arc protection, and a HRC fuse and not a piddly little 20mm
glass one. There is some cheap kit on ebay, but I would be wary until
you have seen exactly how its constructed.

I think you'll find that those fuses are actually semiconductor rated
devices. Designed to protect the electronics. It's an easy trap for
the unwary to fall into though as they do look like a bog standard
ceramic in some cases.

A DIY system is hardly going to be certified by the person dealing
with it, so I would suggest anyone having a solid idea of what they
are testing, could do the job with a cheap multimeter and a few
ancilliary bits & bobs. I would have serious doubts that any DIY
practicioner would "routinely" make test connections to live circuits
incidentally. so wear & tear shouldn't be a major factor to contend
with.

Personally now for the most part I use a none contact device, and
although the thing, like any instrument "needs interpreting", it gives
a good indication and has saved me getting a meter out on many, many
occasions.

Whatever way it's dressed up, testing wiring is just an application
and understanding of Ohm's law. In my experience even some of the
cheapest junk on the market will provide measurements of more than
adequate accuracy.

Now if you want something that's still useable after trying to find
out how many Amps can come out of your 13A socket, a different level
of instrument would probably be needed. I still wouldn't be too
surprised if it failed to function after the fuse replacement though.

AB

On Wed, 07 Aug 2013 11:37:05 +0100, Archibald wrote:

Whatever way it's dressed up, testing wiring is just an application and
understanding of Ohm's law. In my experience even some of the cheapest
junk on the market will provide measurements of more than adequate
accuracy.

So how do you propose to test the insulation at 500V?

--
Use the BIG mirror service in the UK: http://www.mirrorservice.org
My posts (including this one) are my copyright and if @diy_forums on
Twitter wish to tweet them they can pay me £30 a post
*lightning surge protection* - a w_tom conductor

In article ,
Bob Eager wrote:
On Wed, 07 Aug 2013 11:37:05 +0100, Archibald wrote:

Whatever way it's dressed up, testing wiring is just an application and
understanding of Ohm's law. In my experience even some of the cheapest
junk on the market will provide measurements of more than adequate
accuracy.

So how do you propose to test the insulation at 500V?

Out of interest, I wonder just how often such a high voltage is needed
when testing household wiring for poor insulation - especially with new or
recent wiring. I'd say a simple resistance test with a decent DVM would be
more than ok in the vast majority of cases. Might be different when
checking ancient wiring.

I haven't the experience of the likes of Adam, but have yet to come across
a fault like this that a DVM doesn't show up. And yes, I do have a high
voltage insulation tester.

--
*Of course I'm against sin; I'm against anything that I'm too old to enjoy.

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

On Wed, 07 Aug 2013 13:16:06 +0100, "Dave Plowman (News)"
wrote:

In article ,
Bob Eager wrote:
On Wed, 07 Aug 2013 11:37:05 +0100, Archibald wrote:

Whatever way it's dressed up, testing wiring is just an application and
understanding of Ohm's law. In my experience even some of the cheapest
junk on the market will provide measurements of more than adequate
accuracy.

So how do you propose to test the insulation at 500V?

Out of interest, I wonder just how often such a high voltage is needed
when testing household wiring for poor insulation - especially with new or
recent wiring. I'd say a simple resistance test with a decent DVM would be
more than ok in the vast majority of cases. Might be different when
checking ancient wiring.

I haven't the experience of the likes of Adam, but have yet to come across
a fault like this that a DVM doesn't show up. And yes, I do have a high
voltage insulation tester.

Precisely! I too have an insulation tester available. I have never
used it at home. Should the need for a high volts test arise, I have
an old flashgun somewhere that would function perfectly as the source.



I would hazard a guess that even an old mobile phone could generate
the Voltage if there were a few diodes and capacitors to hand.
Likewise a car battery along with a suitable limiting load will
indicate any earth bond problems. Assuming we know V and a reliable
bit of the "R", then our Two for four quid [Yes Maplin were selling
DMMS at this price], meter would reliably tell us the current flow,
and I'm sure the earth bond resistance wouldn't take a genious to find
after that. Although in all fairness this couldn't hope to compete
with the 1kV earth bond test Voltage the cretins that used to test our
companies tools nominated oneach and every one of our class1 PAT
cetificates.

Any domestic leakage would more often than not be due to moisture. Who
waits for a downpour before testing?

My main fear would be water across live & neutral or an arcing
connection feeding a resistive load. Both these scenarios can generate
a lot of heat before the supply fails, whereas leakage to ground or
overcurrent events hardly ever need any form of test equipment to
locate these day's.

AB

In article ,
Dave Plowman (News) wrote:
In article ,
Bob Eager wrote:
On Wed, 07 Aug 2013 11:37:05 +0100, Archibald wrote:

Whatever way it's dressed up, testing wiring is just an application
and understanding of Ohm's law. In my experience even some of the
cheapest junk on the market will provide measurements of more than
adequate accuracy.

So how do you propose to test the insulation at 500V?

Out of interest, I wonder just how often such a high voltage is needed
when testing household wiring for poor insulation - especially with new or
recent wiring. I'd say a simple resistance test with a decent DVM would be
more than ok in the vast majority of cases. Might be different when
checking ancient wiring.

I haven't the experience of the likes of Adam, but have yet to come across
a fault like this that a DVM doesn't show up. And yes, I do have a high
voltage insulation tester.

I have come across many, both in wiring, extension cables and fittings
(PATing). I used to have a lovely hand Megger running off 6x AA cells.
Unfortunately, a cell exploded inside and F***ed up the contacts.

--
From KT24

Using a RISC OS computer running v5.18

On Wed, 07 Aug 2013 14:01:32 +0100, charles
wrote:

In article ,
Dave Plowman (News) wrote:
In article ,
Bob Eager wrote:
On Wed, 07 Aug 2013 11:37:05 +0100, Archibald wrote:

Whatever way it's dressed up, testing wiring is just an application
and understanding of Ohm's law. In my experience even some of the
cheapest junk on the market will provide measurements of more than
adequate accuracy.

So how do you propose to test the insulation at 500V?

Out of interest, I wonder just how often such a high voltage is needed
when testing household wiring for poor insulation - especially with new or
recent wiring. I'd say a simple resistance test with a decent DVM would be
more than ok in the vast majority of cases. Might be different when
checking ancient wiring.

I haven't the experience of the likes of Adam, but have yet to come across
a fault like this that a DVM doesn't show up. And yes, I do have a high
voltage insulation tester.

I have come across many, both in wiring, extension cables and fittings
(PATing). I used to have a lovely hand Megger running off 6x AA cells.
Unfortunately, a cell exploded inside and F***ed up the contacts.
???
You have to be joking! The only fittings I have had fail a
leakage test are those ancient bakelite things that probably started
off wet anyway. The stink was almost as effective as a meter.

If you are getting insulation fails on installation, its time to come
clean on where you are buying your hardware from. It isn't from a car
boot sale on a rainy weekend perchance?


Portable appliances aren't really something a DIY type would normally
test BTW, You'r surely not suggesting someone tucks a PAT tester
amongst the groceries next time they get a kettle from Asda?

AB

In article ,
charles wrote:
I haven't the experience of the likes of Adam, but have yet to come
across a fault like this that a DVM doesn't show up. And yes, I do
have a high voltage insulation tester.

I have come across many, both in wiring, extension cables and fittings
(PATing).

Quite - but did you also do a test with an ordinary DVM to see if it too
showed the fault?

I used to have a lovely hand Megger running off 6x AA cells.
Unfortunately, a cell exploded inside and F***ed up the contacts.

What I'm looking for is an insulation etc fault that only shows up at high
voltage.

--
*I wish the buck stopped here. I could use a few.

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

In article , Archibald
wrote:
On Wed, 07 Aug 2013 14:01:32 +0100, charles
wrote:

In article , Dave Plowman (News)
wrote:
In article , Bob Eager
wrote:
On Wed, 07 Aug 2013 11:37:05 +0100, Archibald wrote:

Whatever way it's dressed up, testing wiring is just an
application and understanding of Ohm's law. In my experience even
some of the cheapest junk on the market will provide measurements
of more than adequate accuracy.

So how do you propose to test the insulation at 500V?

Out of interest, I wonder just how often such a high voltage is needed
when testing household wiring for poor insulation - especially with
new or recent wiring. I'd say a simple resistance test with a decent
DVM would be more than ok in the vast majority of cases. Might be
different when checking ancient wiring.

I haven't the experience of the likes of Adam, but have yet to come
across a fault like this that a DVM doesn't show up. And yes, I do
have a high voltage insulation tester.

I have come across many, both in wiring, extension cables and fittings
(PATing). I used to have a lovely hand Megger running off 6x AA cells.
Unfortunately, a cell exploded inside and F***ed up the contacts.
??? You have to be joking! The only fittings I have had fail a leakage
test are those ancient bakelite things that probably started off wet
anyway. The stink was almost as effective as a meter.

If you are getting insulation fails on installation, its time to come
clean on where you are buying your hardware from. It isn't from a car
boot sale on a rainy weekend perchance?

The only time I've had an insulation fault on installation was when
installing MICC to my garage (in 1968). You are supposed to use a megger
when doing that. It was simply a matter of removing the pot, running a
blowlamp over the end of the cable & repotting. On the other hand I have
had wiring insulation fail over a hot light fitting. It didn't show up on a
multimeter..


Portable appliances aren't really something a DIY type would normally
test BTW, You'r surely not suggesting someone tucks a PAT tester amongst
the groceries next time they get a kettle from Asda?

no, but I've just been to LIDL who sell a wide range of tools

--
From KT24

Using a RISC OS computer running v5.18

In article ,
Dave Plowman (News) wrote:
In article ,
charles wrote:
I haven't the experience of the likes of Adam, but have yet to come
across a fault like this that a DVM doesn't show up. And yes, I do
have a high voltage insulation tester.

I have come across many, both in wiring, extension cables and fittings
(PATing).

Quite - but did you also do a test with an ordinary DVM to see if it too
showed the fault?

I used to have a lovely hand Megger running off 6x AA cells.
Unfortunately, a cell exploded inside and F***ed up the contacts.

What I'm looking for is an insulation etc fault that only shows up at high
voltage.

500v will track across a gap which 9v will not pass.

--
From KT24

Using a RISC OS computer running v5.18

On 07/08/2013 11:37, Archibald wrote:
On Mon, 05 Aug 2013 12:56:12 +0100, John Rumm

[1] This is one of those occasions (where you may be routinely making
connections to live circuits) where you *must* get something that is
properly designed to do the job safely - that means decent input
protection, arc protection, and a HRC fuse and not a piddly little 20mm
glass one. There is some cheap kit on ebay, but I would be wary until
you have seen exactly how its constructed.

I think you'll find that those fuses are actually semiconductor rated
devices. Designed to protect the electronics.

No, you don't need HRC fuses and blast protection chambers to protect
electronics!

It's an easy trap for
the unwary to fall into though as they do look like a bog standard
ceramic in some cases.

Not sure what kind of fuse you have in mind. Most cheap meters will have
a 20mm glass cartridge fuse, inline with the current measurement ranges
(although often not the highest range). They may not even have any fuse
inline when used on other ranges.

Hence these meters are not suitable for making measurements on high
energy locations (e.g. inside a consumer unit)

A DIY system is hardly going to be certified by the person dealing
with it, so I would suggest anyone having a solid idea of what they
are testing, could do the job with a cheap multimeter and a few
ancilliary bits & bobs. I would have serious doubts that any DIY
practicioner would "routinely" make test connections to live circuits
incidentally. so wear & tear shouldn't be a major factor to contend
with.

I think you are missing the point. While you can make many useful tests
with a multimeter, even a cheap one, there are a number of places where
you can't do so safely.

Also how do you carry out a full RCD test, or Insulation resistance test
with a MM? You could produce a PSSC result perhaps, but would also have
difficulty measuring the earth loop impedance.

Personally now for the most part I use a none contact device, and
although the thing, like any instrument "needs interpreting", it gives
a good indication and has saved me getting a meter out on many, many
occasions.

These are fine for go/no go indications, but they don't give you a
complete set of test capabilities.

Whatever way it's dressed up, testing wiring is just an application
and understanding of Ohm's law. In my experience even some of the
cheapest junk on the market will provide measurements of more than
adequate accuracy.

Indeed, and usually you will live to tell the tale, but sometimes you wont.

Now if you want something that's still useable after trying to find
out how many Amps can come out of your 13A socket, a different level
of instrument would probably be needed. I still wouldn't be too
surprised if it failed to function after the fuse replacement though.

The purpose of the input protection is to protect you primarily and not
the meter. If you are taking a voltage reading close to your consumer
unit, and the meter experiences a 10kV transient, its better that it
dies in the process of blowing its fuse and popping a few MOVs, tham
allowing an arc flash to engulf the user.



--
Cheers,

John.

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

On 07/08/2013 14:51, Dave Plowman (News) wrote:
In article ,
charles wrote:
I haven't the experience of the likes of Adam, but have yet to come
across a fault like this that a DVM doesn't show up. And yes, I do
have a high voltage insulation tester.

I have come across many, both in wiring, extension cables and fittings
(PATing).

Quite - but did you also do a test with an ordinary DVM to see if it too
showed the fault?

I used to have a lovely hand Megger running off 6x AA cells.
Unfortunately, a cell exploded inside and F***ed up the contacts.

What I'm looking for is an insulation etc fault that only shows up at high
voltage.

I had one today in someone's kitchen - old socket on the end of a 2m
spur. L to E measurement on a MM read open circuit, and at 500V was
showing around 54 M ohms (still in spec - but poor enough to warrant
replacement shortly)


--
Cheers,

John.

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

In article ,
charles wrote:
What I'm looking for is an insulation etc fault that only shows up at
high voltage.

500v will track across a gap which 9v will not pass.

Yes - I know the theory. Just wondering how often it happens in practice.

--
*Everyone has a photographic memory. Some don't have film *

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

In article ,
John Rumm wrote:
What I'm looking for is an insulation etc fault that only shows up at
high voltage.

I had one today in someone's kitchen - old socket on the end of a 2m
spur. L to E measurement on a MM read open circuit, and at 500V was
showing around 54 M ohms (still in spec - but poor enough to warrant
replacement shortly)


yes - that was one of the possibilities I was thinking of. But was more
interested in testing one's own new work, etc, DIY wise. You'd not find
any ancient wiring here. ;-)

--
*Beware - animal lover - brakes for pussy*

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

In article ,
Dave Plowman (News) wrote:
In article ,
charles wrote:
What I'm looking for is an insulation etc fault that only shows up at
high voltage.

500v will track across a gap which 9v will not pass.

Yes - I know the theory. Just wondering how often it happens in practice.

enough to make me cautious - and use the correct measuring kit.

--
From KT24

Using a RISC OS computer running v5.18

On Wednesday, August 7, 2013 5:42:13 PM UTC+1, John Rumm wrote:
On 07/08/2013 11:37, Archibald wrote:

snip
I think you'll find that those fuses are actually semiconductor rated
devices. Designed to protect the electronics.

No, you don't need HRC fuses and blast protection chambers to protect
electronics!

It's an easy trap for
the unwary to fall into though as they do look like a bog standard
ceramic in some cases.

Not sure what kind of fuse you have in mind. Most cheap meters will have
a 20mm glass cartridge fuse, inline with the current measurement ranges
(although often not the highest range). They may not even have any fuse
inline when used on other ranges.

The hand-held meter I'm using (which wasn't particularly expensive) uses these:-
http://uk.farnell.com/cooper-bussman...vac/dp/1454149
It's a real pain when someone 'borrows' your meter and blows the fuse - at that price we don't keep lots of them in stock...

On 07/08/2013 18:10, Dave Plowman (News) wrote:
In article ,
John Rumm wrote:
What I'm looking for is an insulation etc fault that only shows up at
high voltage.

I had one today in someone's kitchen - old socket on the end of a 2m
spur. L to E measurement on a MM read open circuit, and at 500V was
showing around 54 M ohms (still in spec - but poor enough to warrant
replacement shortly)


yes - that was one of the possibilities I was thinking of. But was more
interested in testing one's own new work, etc, DIY wise. You'd not find
any ancient wiring here. ;-)

On new wiring you would only normally expect to see interesting stuff on
IR tests after water ingress or rodent damage IME.

(you may recall my tale of working back through former neighbours
cooker, slowly removing more and more bits before eventually tracing the
fault to a damp plug - when all I had left of the cooker was its back
cover and its mains lead!)


--
Cheers,

John.

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

On 07/08/2013 18:29, wrote:
On Wednesday, August 7, 2013 5:42:13 PM UTC+1, John Rumm wrote:
On 07/08/2013 11:37, Archibald wrote:

snip
I think you'll find that those fuses are actually semiconductor rated
devices. Designed to protect the electronics.

No, you don't need HRC fuses and blast protection chambers to protect
electronics!

It's an easy trap for
the unwary to fall into though as they do look like a bog standard
ceramic in some cases.

Not sure what kind of fuse you have in mind. Most cheap meters will have
a 20mm glass cartridge fuse, inline with the current measurement ranges
(although often not the highest range). They may not even have any fuse
inline when used on other ranges.

The hand-held meter I'm using (which wasn't particularly expensive) uses these:-
http://uk.farnell.com/cooper-bussman...vac/dp/1454149
It's a real pain when someone 'borrows' your meter and blows the fuse - at that price we don't keep lots of them in stock...

Yup, that is a proper HRC fuse... it can interrupt a 10kA fault current.
Some of the glass cartridge fuses can't manage more than 20A


--
Cheers,

John.

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

On 07/08/13 17:52, Dave Plowman (News) wrote:
In article ,
charles wrote:
What I'm looking for is an insulation etc fault that only shows up at
high voltage.
500v will track across a gap which 9v will not pass.
Yes - I know the theory. Just wondering how often it happens in practice.

when I have seen it it has been down to damaged insulation and usually
the spark arcs creating a sort of strange carbon resistor that sputters
and arcs.


--
Ineptocracy

(in-ep-toc-ra-cy) €“ a system of government where the least capable to lead are elected by the least capable of producing, and where the members of society least likely to sustain themselves or succeed, are rewarded with goods and services paid for by the confiscated wealth of a diminishing number of producers.

On Wed, 07 Aug 2013 17:42:13 +0100, John Rumm
wrote:

On 07/08/2013 11:37, Archibald wrote:
On Mon, 05 Aug 2013 12:56:12 +0100, John Rumm

[1] This is one of those occasions (where you may be routinely making
connections to live circuits) where you *must* get something that is
properly designed to do the job safely - that means decent input
protection, arc protection, and a HRC fuse and not a piddly little 20mm
glass one. There is some cheap kit on ebay, but I would be wary until
you have seen exactly how its constructed.

I think you'll find that those fuses are actually semiconductor rated
devices. Designed to protect the electronics.

No, you don't need HRC fuses and blast protection chambers to protect
electronics!

It's an easy trap for
the unwary to fall into though as they do look like a bog standard
ceramic in some cases.



Not sure what kind of fuse you have in mind. Most cheap meters will have
a 20mm glass cartridge fuse, inline with the current measurement ranges
(although often not the highest range). They may not even have any fuse
inline when used on other ranges.

Probably as effective as the semiconductor rated devices fitted to the
Flukes & similar. Personally I wouln't bother too much about fuses
anyway. As you state, the higher current shunts are not fused and at
the lower end of the ranges, the components often beat the fuse hands
down on the route to destruction.


Hence these meters are not suitable for making measurements on high
energy locations (e.g. inside a consumer unit)

Bilge! I use a Wickes device, glass fuse, not sure what current
because it came out of my bits box last time I tried to check a 110V
supply when tweaking a current loop. It has actually lasted aroud five
years which is a miracle considering it gets soaked in water, acid,
caustic and all the rest of the gunge that ends up in the water
treatment system.

I use it for personal domestic wiring and industrial three phase 415V
supplies. I could splash out a fortune on test gear, but I know it's
going to have a short life whatever its price tag, so I just go for
something that is around 1kv max DC & AC, resolves down to a
microVolt/ microAmp and will do DC & AC Amps. Most meters have an
adequate Ohms range, so that's it.

Whatever meter I have bought, I never did bother trying to find out if
it was even fused before purchase, there isn't too much point.

Incidentally, years back I had an AVO eight, the industry standard
hyper priced instrument of my youth. I dont even think it was fused.
If it was I never changed the thing and it did have an overload or
two! That was wat led me to buy cheap incidentally. Very similar
specifications at a price range that meant you could buy twenty or so
cheapos for the cost of an AVO.


A DIY system is hardly going to be certified by the person dealing
with it, so I would suggest anyone having a solid idea of what they
are testing, could do the job with a cheap multimeter and a few
ancilliary bits & bobs. I would have serious doubts that any DIY
practicioner would "routinely" make test connections to live circuits
incidentally. so wear & tear shouldn't be a major factor to contend
with.

I think you are missing the point. While you can make many useful tests
with a multimeter, even a cheap one, there are a number of places where
you can't do so safely.

Also how do you carry out a full RCD test, or Insulation resistance test
with a MM? You could produce a PSSC result perhaps, but would also have
difficulty measuring the earth loop impedance.

I'm not sure what newsgroup you think you are on but this is uk.d-i-y.
No I do not think I would have difficulty measuring earth loop
impedance incidentally.

I have never completed an earth loop impedance test on any of my
wiring BTW even though we have dedicated testers for the installation
personnel, I would doubt that many DIY people have either.


Personally now for the most part I use a none contact device, and
although the thing, like any instrument "needs interpreting", it gives
a good indication and has saved me getting a meter out on many, many
occasions.

These are fine for go/no go indications, but they don't give you a
complete set of test capabilities.

Thank you, I feel most enlightened.

Whatever way it's dressed up, testing wiring is just an application
and understanding of Ohm's law. In my experience even some of the
cheapest junk on the market will provide measurements of more than
adequate accuracy.

Indeed, and usually you will live to tell the tale, but sometimes you wont.

It isn't the test equipment! none of it's perfect and it does not
replace common sense. I actually watched a pillock unpack one of those
two wire Voltage prodders from RS, fit the batteries and use it to
check a three phase socket in the yard after he had isolated it. He
was then about to remove the socket, before I stopped him and
suggested he try his new tester on something "live" first.

The problem isn't with the equipment! Give me someone with a brain and
a bit of experience any day, any idiot can blow his cash

Now if you want something that's still useable after trying to find
out how many Amps can come out of your 13A socket, a different level
of instrument would probably be needed. I still wouldn't be too
surprised if it failed to function after the fuse replacement though.



The purpose of the input protection is to protect you primarily and not
the meter. If you are taking a voltage reading close to your consumer
unit, and the meter experiences a 10kV transient, its better that it
dies in the process of blowing its fuse and popping a few MOVs, tham
allowing an arc flash to engulf the user.

Really? Is this the same mains that all those TV's radios, table
lamps and such like are connected to? Perhaps you should go on a
crusade to fit better fuses on all this equipment before the users are
engulfed in a searing hot plasma, or is there some magical barrier in
a consumenr unit that stops transients dead?

Test equipment fuses are not semiconductor rated to protect the user!
I suppose people are "semiconductors", but they dont fit semiconductor
fuses to toasters do they? If they see fit to put the things in meters
and not toasters does it not suggest that they may not after all be
trying to protect the user?

AB

Not sure what kind of fuse you have in mind. Most cheap meters will have
a 20mm glass cartridge fuse, inline with the current measurement ranges
(although often not the highest range). They may not even have any fuse
inline when used on other ranges.

Probably as effective as the semiconductor rated devices fitted to the
Flukes & similar. Personally I wouln't bother too much about fuses
anyway. As you state, the higher current shunts are not fused and at
the lower end of the ranges, the components often beat the fuse hands
down on the route to destruction.


Hence these meters are not suitable for making measurements on high
energy locations (e.g. inside a consumer unit)

Bilge! I use a Wickes device, glass fuse, not sure what current
because it came out of my bits box last time I tried to check a 110V
supply when tweaking a current loop. It has actually lasted aroud five
years which is a miracle considering it gets soaked in water, acid,
caustic and all the rest of the gunge that ends up in the water
treatment system.

I use it for personal domestic wiring and industrial three phase 415V
supplies. I could splash out a fortune on test gear, but I know it's
going to have a short life whatever its price tag, so I just go for
something that is around 1kv max DC & AC, resolves down to a
microVolt/ microAmp and will do DC & AC Amps. Most meters have an
adequate Ohms range, so that's it.

Whatever meter I have bought, I never did bother trying to find out if
it was even fused before purchase, there isn't too much point.


So your working on those sorts of systems and are that tight to buy a
half decent pro meter?. You can get good Fluke meters on e-bay for
around 40 to 50 quid sometimes. I managed to get one from a S/H test
equipment supplier c/w decent rated leads and fuses etc for that sort of
money...

Buggered if I'd use a cheap chinkie one of dubious origin;!...
--
Tony Sayer

On Wed, 07 Aug 2013 21:38:33 +0100, Archibald wrote:

Incidentally, years back I had an AVO eight, the industry standard hyper
priced instrument of my youth. I dont even think it was fused.

They have a fuse, and a cut-out.

--
Use the BIG mirror service in the UK: http://www.mirrorservice.org
My posts (including this one) are my copyright and if @diy_forums on
Twitter wish to tweet them they can pay me £30 a post
*lightning surge protection* - a w_tom conductor