A I liable to cause a trip by using a volmeter between live and earth - to
trace a circuit?

On 31/10/2019 18:10, John wrote:
A I liable to cause a trip by using a volmeter between live and earth - to
trace a circuit?

Not unless it is a very old one drawing serious current.
Why can't you trace using live to neutral?

I prefer a neon screwdriver myself even though they are deprecated.

All bets are off if you short live to earth though.

--
Regards,
Martin Brown

On Thursday, 31 October 2019 18:10:31 UTC, John wrote:
A I liable to cause a trip by using a volmeter between live and earth - to
trace a circuit?

Shouldn't do.

Assuming a typical digital meter impedance of 20 Mohm, you'll be loading the circuit by 0.02 mA, which shouldn't trip an RCD or ELCB.

If my calcs are right of course.

Owain

On Thursday, 31 October 2019 18:10:31 UTC, John wrote:
A I liable to cause a trip by using a volmeter between live and earth - to
trace a circuit?

no chance. Unless you short it out by accident.


NT

On Thu, 31 Oct 2019 18:10:27 +0000, John wrote:

A I liable to cause a trip by using a volmeter between live and earth -
to trace a circuit?

Yes.
Depending on what make/model of voltmeter.
A multimeter generally doesnt trip the RCD,as thye have avery high
impedance.
Some of the cheaper ones, even made by a 'decent' brand can cause the RCD
to trip, if the correct sequence is not followed.
The Fluke T100 would trip the RCD unless a L-N voltage reading is taken
first. No idea how it worked like that, but check your voltmeter manual
first.

On Thursday, 31 October 2019 18:43:29 UTC, Alan wrote:
On Thu, 31 Oct 2019 18:10:27 +0000, John wrote:

A I liable to cause a trip by using a volmeter between live and earth -
to trace a circuit?

Yes.
Depending on what make/model of voltmeter.
A multimeter generally doesnt trip the RCD,as thye have avery high
impedance.
Some of the cheaper ones, even made by a 'decent' brand can cause the RCD
to trip, if the correct sequence is not followed.
The Fluke T100 would trip the RCD unless a L-N voltage reading is taken
first. No idea how it worked like that, but check your voltmeter manual
first.

even rock bottom $2 analogue multimeters are 1k/volt, on a 250v scale that's 1mA, less on a higher v scale. There's no way that's tripping an RCD unless it's right on the edge already, in which case you have a problem that needs sorting. And that tripping a voltage ELCB? No chance at all.


NT

On 31/10/2019 18:43, Alan wrote:
On Thu, 31 Oct 2019 18:10:27 +0000, John wrote:

A I liable to cause a trip by using a volmeter between live and earth -
to trace a circuit?

Yes.
Depending on what make/model of voltmeter.
A multimeter generally doesnt trip the RCD,as thye have avery high
impedance.
Some of the cheaper ones, even made by a 'decent' brand can cause the RCD
to trip, if the correct sequence is not followed.


The Fluke T100 would trip the RCD unless a L-N voltage reading is taken
first. No idea how it worked like that, but check your voltmeter manual
first.


It was meant to work like that. A bit of a ******* if there is no local
neutral.


--
Adam

Anything is possible but I'd hope not, but what are you actually trying to
find?
Brian

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"John" wrote in message
2.222...
A I liable to cause a trip by using a volmeter between live and earth - to
trace a circuit?

So what does it mean if there is 10v on earth to neutral?
Brian

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"Martin Brown" wrote in message
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On 31/10/2019 18:10, John wrote:
A I liable to cause a trip by using a volmeter between live and earth -
to
trace a circuit?

Not unless it is a very old one drawing serious current.
Why can't you trace using live to neutral?

I prefer a neon screwdriver myself even though they are deprecated.

All bets are off if you short live to earth though.

--
Regards,
Martin Brown

On 31/10/2019 18:57, wrote:
On Thursday, 31 October 2019 18:43:29 UTC, Alan wrote:
On Thu, 31 Oct 2019 18:10:27 +0000, John wrote:

A I liable to cause a trip by using a volmeter between live and earth -
to trace a circuit?

Yes.
Depending on what make/model of voltmeter.
A multimeter generally doesnt trip the RCD,as thye have avery high
impedance.
Some of the cheaper ones, even made by a 'decent' brand can cause the RCD
to trip, if the correct sequence is not followed.
The Fluke T100 would trip the RCD unless a L-N voltage reading is taken
first. No idea how it worked like that, but check your voltmeter manual
first.

even rock bottom $2 analogue multimeters are 1k/volt, on a 250v scale that's 1mA, less on a higher v scale. There's no way that's tripping an RCD unless it's right on the edge already, in which case you have a problem that needs sorting. And that tripping a voltage ELCB? No chance at all.

It has not been made clear if it is a voltage or current operated ELCB.

The OP may be using older terminology and meant RCD.


--
Adam

In article ,
Brian Gaff \(Sofa\) wrote:
So what does it mean if there is 10v on earth to neutral?
Brian

there's an unbalanced load between the 3 phases.

--
from KT24 in Surrey, England
"I'd rather die of exhaustion than die of boredom" Thomas Carlyle

On 31/10/2019 21:43, charles wrote:
In article ,
Brian Gaff \(Sofa\) wrote:
So what does it mean if there is 10v on earth to neutral?
Brian

there's an unbalanced load between the 3 phases.

Or a parallel run of cable close enough to induce a voltage on the one
you're measuring if the neutral is disconnected. I have one cable that
when isolated at the double pole isolator, floats at 90V to earth if
there is no load across it!

SteveW

On 31/10/2019 20:28, Brian Gaff (Sofa) wrote:

So what does it mean if there is 10v on earth to neutral?

If you have TN-S earthing, then you could see a fair potential
difference to earth since the N carries high current but does not have
zero impedance - so there will be some voltage rise between your
property and the substation (and the live will typically see a
comparable voltage drop). The earth however will be a close
approximation of the Neutral potential at the substation.

With TT you can see a similar magnitude. With TN-C-S you can still see
some, but its only the result of current flow in your property, and so
will vary more depending on where you measure it.


--
Cheers,

John.

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On 31/10/2019 18:10, John wrote:

A I liable to cause a trip by using a volmeter between live and earth - to
trace a circuit?

The short answer is "no" for most "normal" multimeters. However could
you clarify what you mean by ELCB?

Do you mean a current operated ELCB - i.e. what we call a RCD these
days, or do you actually mean a Voltage Operated ELCB (obsolete, but
still installed in some properties).

See:

http://wiki.diyfaq.org.uk/index.php/ELCB



--
Cheers,

John.

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