If I measure the resistance between the live and earth terminals of my
Russell Hobs stainless steel electic kettle I get a reading of about
9M ohms. (using my electonic multimeter)

Is this normal or indicative of a fault which a higher voltage might be
able to jump causing the fuse to blow?

Michael Chare

In an earlier contribution to this discussion,
Michael Chare wrote:

If I measure the resistance between the live and earth terminals of my
Russell Hobs stainless steel electic kettle I get a reading of about
9M ohms. (using my electonic multimeter)

Is this normal or indicative of a fault which a higher voltage might
be able to jump causing the fuse to blow?

Michael Chare

If that same impedance applies at mains frequency, it will cause a current
of just under 30 micro-amps to flow to earth - which is a thousand times
less than the current required to trip an RCD.

I would have thought that this was pretty good - and certainly wouldn't
worry about it.
--
Cheers,
Set Square
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"Set Square" wrote in message
...
In an earlier contribution to this discussion,
Michael Chare wrote:

If I measure the resistance between the live and earth terminals of my
Russell Hobs stainless steel electic kettle I get a reading of about
9M ohms. (using my electonic multimeter)

Is this normal or indicative of a fault which a higher voltage might
be able to jump causing the fuse to blow?

Michael Chare

If that same impedance applies at mains frequency, it will cause a current
of just under 30 micro-amps to flow to earth - which is a thousand times
less than the current required to trip an RCD.

I would have thought that this was pretty good - and certainly wouldn't
worry about it.

My problem is that the kettle has blown two fuses. Before fitting the 2nd fuse I
checked for a short circuit, but not an earth fault. There is now no sign of an
earth fault other than I have described in either the kettle or the supply lead.
The plug that goes into the kettle is similar to that often used on computer
equipment, it could just have had a fault which was burnt away by the fault
current. Unfortunately although the plug appears to be made in two parts I can't
get it apart to make an internal inspection.

--

Michael Chare









--
Cheers,
Set Square
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In an earlier contribution to this discussion,
Michael Chare wrote:

"Set Square" wrote in message
...
In an earlier contribution to this discussion,
Michael Chare wrote:

If I measure the resistance between the live and earth terminals of
my Russell Hobs stainless steel electic kettle I get a reading of
about 9M ohms. (using my electonic multimeter)

Is this normal or indicative of a fault which a higher voltage might
be able to jump causing the fuse to blow?

Michael Chare

If that same impedance applies at mains frequency, it will cause a
current of just under 30 micro-amps to flow to earth - which is a
thousand times less than the current required to trip an RCD.

I would have thought that this was pretty good - and certainly
wouldn't worry about it.

My problem is that the kettle has blown two fuses. Before fitting the
2nd fuse I checked for a short circuit, but not an earth fault.
There is now no sign of an earth fault other than I have described in
either the kettle or the supply lead. The plug that goes into the
kettle is similar to that often used on computer equipment, it could
just have had a fault which was burnt away by the fault current.
Unfortunately although the plug appears to be made in two parts I
can't get it apart to make an internal inspection.


--
Cheers,
Set Square
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It's possible that if there are pinholes in the element, the presence of
water causes a mains-voltage earth leak which doesn't show up in your DC
resistance measurement.

The fuse is blowing is because it's being asked to carry more current than
it can. This might be going to earth - or it might be going through the
element, back to neutral.

Have you got an RCD plug-in adapter, as used with garden tools? If so, use
that with the kettle for a bit and see what happens. If the RCD trips, its
an earth leak. If the fuse blows without the RCD tripping, the element is
taking too much current for some reason. You are using a 13A fuse and not
5A, aren't you?
--
Cheers,
Set Square
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On Thu, 18 Nov 2004 14:49:16 +0000, Michael Chare
strung together this:

If I measure the resistance between the live and earth terminals of my
Russell Hobs stainless steel electic kettle I get a reading of about
9M ohms. (using my electonic multimeter)

Is this normal or indicative of a fault which a higher voltage might be
able to jump causing the fuse to blow?

If you're trying to fault find it don't bother with a multimeter, use
an insulation tester. Buying a new kettle would be cheaper though,
they're not expensive.
--

SJW
A.C.S. Ltd

Michael Chare wrote in
news
If I measure the resistance between the live and earth terminals of my
Russell Hobs stainless steel electic kettle I get a reading of about
9M ohms. (using my electonic multimeter)

Is this normal or indicative of a fault which a higher voltage might be
able to jump causing the fuse to blow?

Michael Chare

You're not holding the croc clips, are you? could be *your* resistance.

TBH, I don't know, but 9 Meg won't hurt anyone, and I _theeenk_ heating
elements may be leaky, and may trip RCDs

mike

"mike ring" wrote in message
2.50...
Michael Chare wrote in
news
If I measure the resistance between the live and earth terminals of my
Russell Hobs stainless steel electic kettle I get a reading of about
9M ohms. (using my electonic multimeter)

Is this normal or indicative of a fault which a higher voltage might be
able to jump causing the fuse to blow?

Michael Chare

You're not holding the croc clips, are you? could be *your* resistance.

TBH, I don't know, but 9 Meg won't hurt anyone, and I _theeenk_ heating
elements may be leaky, and may trip RCDs

You cant measure impedance with a a dmm

Peter