T i m wrote:

> Those 13A fitting 'Mains test plugs' .. are there good one and bad
> ones (generally)

No. A neon is a neon.

They're great for finding faults in circuits that are perfectly
connected and in good condition, but might have topological faults
(swapped connections, no connection). For anything in-between (leakage,
high impedance) then they're beyond useless and possibly dangerous, if
trusted as a safety measure.

If swapped wires are a risk (?!) then they could be useful. For
anything else, then I'm just not sure what you'd expect them to tell
you.

T i m wrote:
> On 21 Aug 2006 05:13:22 -0700, (E-Mail Removed) wrote:
> >T i m wrote:

> >> Those 13A fitting 'Mains test plugs' .. are there good one and bad
> >> ones (generally)
> >
> >No. A neon is a neon.
>
> So none of these devices use further electronics / LED's for example?
> >
> >They're great for finding faults in circuits that are perfectly
> >connected and in good condition, but might have topological faults
> >(swapped connections, no connection). For anything in-between (leakage,
> >high impedance) then they're beyond useless and possibly dangerous, if
> >trusted as a safety measure.
>
> Understood (although I believe there are some 'sophisticated' variants
> on the basic 3 neon jobbies that can also display earth loop impedance
> etc).
> >
> >If swapped wires are a risk (?!) then they could be useful.
>
> Some 'swapped wires' can be a risk can't they (live / earth) or have
> I missed summat (again) ;-(
>
>
> >For
> >anything else, then I'm just not sure what you'd expect them to tell
> >you.
>
> Well nothing, I was just asking if 'you get's what you pays for' with
> these things and it would seem from the other replies for yer basic 3
> neon jobbies the answer is no (unless you only pay a fiver that is)
> ;-)
>
> The background thought (and reason for the question) was have things
> moved on with such devices .. saves all the 'who sold you that then'
> type comments .. ;-(
>
> All the best ..
>
> T i m

As well as the basic 3 neon ones that check for swapped wires, I've
seen more expensive ones that claim to test a bunch of extra stuff, and
iirc have a 3rd indicator mode (as well as on/off). But I dont recall
exactly what they claimed and havent used them. The basic ones can be
assembled for £1 or bought for a few earth pounds.


NT

T i m wrote:

>>No. A neon is a neon.
>
>
> So none of these devices use further electronics / LED's for example?

My one uses three multicolour LEDs which light in various combinations
and colours to indicate different fault conditions.

>>They're great for finding faults in circuits that are perfectly
>>connected and in good condition, but might have topological faults
>>(swapped connections, no connection). For anything in-between (leakage,
>>high impedance) then they're beyond useless and possibly dangerous, if
>>trusted as a safety measure.
>
>
> Understood (although I believe there are some 'sophisticated' variants
> on the basic 3 neon jobbies that can also display earth loop impedance
> etc).

Not seen one that does earth loop, but there are various electronic ones
that can detect more faults than the basic ones.

http://cpc.farnell.com/jsp/endecaSea...cpc/267541.xml
http://cpc.farnell.com/jsp/endecaSea...sp?SKU=IN02208

>>If swapped wires are a risk (?!) then they could be useful.
>
>
> Some 'swapped wires' can be a risk can't they (live / earth) or have
> I missed summat (again) ;-(

ITHM "if swapped wires are likely" (they always present a risk if
present). Also one of the standard tests on new wiring ought to test
polarity at each outlet.

>>For
>>anything else, then I'm just not sure what you'd expect them to tell
>>you.
>
>
> Well nothing, I was just asking if 'you get's what you pays for' with
> these things and it would seem from the other replies for yer basic 3
> neon jobbies the answer is no (unless you only pay a fiver that is)
> ;-)

Some have audio go/nogo indications - handy for brightly lit
environments. Others have more sophisticated fault reporting.


--
Cheers,

John.

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| Internode Ltd - http://www.internode.co.uk |
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T i m <(E-Mail Removed)> wrote in
news:(E-Mail Removed):

>
> Some 'swapped wires' can be a risk can't they (live / earth) or have
> I missed summat (again) ;-(
>
>
No, not this time - mine doesn't detect an earth/neutral cross

mike