A friend complained of getting a shock from their ancient electric
hob. This occurred when they grabbed at a metal handled saucepan on
the hob, while touching the stainless steel sink.

I measured 20 volts between the stainless steel 'spill ring' (which
surrounds each of the hob rings) and a known earth (in this case, the
earth terminal of a nearby socket outlet).

Deeming the age of the hob to be a likely suspect, I have since
replaced this with a new hob. However, the voltage issue remains and I
am still getting 20 volts from the new hob's spill rings! I tried
phoning Moffat to see if this is normal, only to be told that they no
longer operate a technical department for dealing with customer
issues, which I find ridiculous.

So, can anyone here offer up any info or advice as to whether this is
normal for an electric hob, or what might be the cause if this
shouldn't be happening?

Many thanks,
Dean.

wrote in message
...
A friend complained of getting a shock from their ancient electric
hob. This occurred when they grabbed at a metal handled saucepan on
the hob, while touching the stainless steel sink.

I measured 20 volts between the stainless steel 'spill ring' (which
surrounds each of the hob rings) and a known earth (in this case, the
earth terminal of a nearby socket outlet).

Deeming the age of the hob to be a likely suspect, I have since
replaced this with a new hob. However, the voltage issue remains and I
am still getting 20 volts from the new hob's spill rings! I tried
phoning Moffat to see if this is normal, only to be told that they no
longer operate a technical department for dealing with customer
issues, which I find ridiculous.

So, can anyone here offer up any info or advice as to whether this is
normal for an electric hob, or what might be the cause if this
shouldn't be happening?

I would strongly suspect the earth has come adrift somewhere. As you have
changed the hob, you need to check the earth in the supply cabling. At least
that's what I would do first. There may be very high resistance leakage
paths to earth as part of the design. Without an earth, the metalwork will
"float" upwards in voltage. The meter will act as a potential divider in
this case, so the 20V is a bit arbitrary. Certainly I had an identical
problem with a washing machine, which turned out to be a disconnected earth
in the supply cabling.


--
Bob Mannix
(anti-spam is as easy as 1-2-3 - not)

On 1 May, 09:25, "Bob Mannix" wrote:
I would strongly suspect the earth has come adrift somewhere. As you have
changed the hob, you need to check the earth in the supply cabling. At least
that's what I would do first. There may be very high resistance leakage
paths to earth as part of the design. Without an earth, the metalwork will
"float" upwards in voltage. The meter will act as a potential divider in
this case, so the 20V is a bit arbitrary. Certainly I had an identical
problem with a washing machine, which turned out to be a disconnected earth
in the supply cabling.

--
Bob Mannix
(anti-spam is as easy as 1-2-3 - not)

Hi Bob.

Yes, the 'floating up' did seem to be an issue, as different rings
gave various readings, and this did vary between 7 and 20 volts. I
will check the continuity of the supply earth. Could it also be a
breakage in the bonding to the sink?

cheers,
Dean.

"deano" wrote in message
...
On 1 May, 09:25, "Bob Mannix" wrote:
I would strongly suspect the earth has come adrift somewhere. As you have
changed the hob, you need to check the earth in the supply cabling. At
least
that's what I would do first. There may be very high resistance leakage
paths to earth as part of the design. Without an earth, the metalwork
will
"float" upwards in voltage. The meter will act as a potential divider in
this case, so the 20V is a bit arbitrary. Certainly I had an identical
problem with a washing machine, which turned out to be a disconnected
earth
in the supply cabling.

--
Bob Mannix
(anti-spam is as easy as 1-2-3 - not)

Hi Bob.

Yes, the 'floating up' did seem to be an issue, as different rings
gave various readings, and this did vary between 7 and 20 volts. I
will check the continuity of the supply earth. Could it also be a
breakage in the bonding to the sink?

No, very unlikely, as the sink will be bonded all over the place and doesn't
have a supply to it. Always suspect the thing with a power lead!


--
Bob Mannix
(anti-spam is as easy as 1-2-3 - not)

In article
,
wrote:
I measured 20 volts between the stainless steel 'spill ring' (which
surrounds each of the hob rings) and a known earth (in this case, the
earth terminal of a nearby socket outlet).

You'd first need to check the 'known earth' is indeed just that. It could
be the faulty one. And don't just assume the house earth is good either.

--
*Horn broken. - Watch for finger.

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

In uk.d-i-y deano wrote:
On 1 May, 09:25, "Bob Mannix" wrote:
I would strongly suspect the earth has come adrift somewhere. As you have
changed the hob, you need to check the earth in the supply cabling. At least
that's what I would do first. There may be very high resistance leakage
paths to earth as part of the design. Without an earth, the metalwork will
"float" upwards in voltage. The meter will act as a potential divider in
this case, so the 20V is a bit arbitrary. Certainly I had an identical
problem with a washing machine, which turned out to be a disconnected earth
in the supply cabling.

--
Bob Mannix
(anti-spam is as easy as 1-2-3 - not)

Hi Bob.

Yes, the 'floating up' did seem to be an issue, as different rings
gave various readings, and this did vary between 7 and 20 volts. I
will check the continuity of the supply earth. Could it also be a
breakage in the bonding to the sink?

It's not a requirement for the sink to be bonded. However since there
should be main bonding to the incoming water main and this is nearly
always under the sink it's pretty likely that the sink is connected to
the mains earth.

I'd check the earth continuity to the hob first, then check to see how
(if?) the sink is earthed.

--
Chris Green

wrote in message
...
A friend complained of getting a shock from their ancient electric
hob. This occurred when they grabbed at a metal handled saucepan on
the hob, while touching the stainless steel sink.

I measured 20 volts between the stainless steel 'spill ring' (which
surrounds each of the hob rings) and a known earth (in this case, the
earth terminal of a nearby socket outlet).

Deeming the age of the hob to be a likely suspect, I have since
replaced this with a new hob. However, the voltage issue remains and I
am still getting 20 volts from the new hob's spill rings! I tried
phoning Moffat to see if this is normal, only to be told that they no
longer operate a technical department for dealing with customer
issues, which I find ridiculous.

So, can anyone here offer up any info or advice as to whether this is
normal for an electric hob, or what might be the cause if this
shouldn't be happening?

Many thanks,
Dean.

Poor earthing can certainly play hob with your hob. I had to search "hob" to
learn it is an English cooktop. How about that. Y'know, Pearl Buck was
one of the first people to recognize the value of grounding. She summed it
up in her book, "The Good Earth."
Tom

deano laid this down on his screen :
Hi Bob.

Yes, the 'floating up' did seem to be an issue, as different rings
gave various readings, and this did vary between 7 and 20 volts. I
will check the continuity of the supply earth. Could it also be a
breakage in the bonding to the sink?

It could be a number of things...

It could be the sink which lacks an earth and it has some voltage on it
which you are measuring to the properly earthed cooker.

The cooker might lack an earth and your assumption is correct.

It could be that the spill rings are not earthed and are having some
voltage induced onto them.

Th best way to work out which, is to make our measurements against a
known good earth. Your 13amp socket should have a good earth on the
upper larger pin - could you safely make use of that?

From a good earth you need to take another set of measurements. There
should be no voltage at all as measured at the sink and the main body
of the cooker.

If the spill rings are firmly attached to the metal body of the cooker,
then there should be no voltage on those either. If they are not
attached, then you can expect some voltage - but there will be no
current behind the voltage - perhaps a few micro-amps at most.

All unearthed metal in or near the field of passing cable, will pick up
a measurable voltage - that is perfectly normal and there is no danger.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

On May 1, 12:17*am, wrote:
A friend complained of getting a shock from their ancient electric
hob. This occurred when they grabbed at a metal handled saucepan on
the hob, while touching the stainless steel sink.

I measured 20 volts between the stainless steel 'spill ring' (which
surrounds each of the hob rings) and a known earth (in this case, the
earth terminal of a nearby socket outlet).

Deeming the age of the hob to be a likely suspect, I have since
replaced this with a new hob. However, the voltage issue remains and I
am still getting 20 volts from the new hob's spill rings! I tried
phoning Moffat to see if this is normal, only to be told that they no
longer operate a technical department for dealing with customer
issues, which I find ridiculous.

So, can anyone here offer up any info or advice as to whether this is
normal for an electric hob, or what might be the cause if this
shouldn't be happening?

Many thanks,
Dean.

You are apparently not in the US, if you were I would say the main
bonding jumper is missing, because I had the same thing happen to me
on an inpection job except I laid my metal tablet on the electric
stove and touched it and the metal sink at the same time. A hot wire
was pinched at a pump cover in the basement and the main bonding
jumper was missing so the breakers could not trip. All the water
pipes were at 120 volts, and the stove was grounded using the neutral
so there was 120 volts from the stove to the metal sink.

On 1 May, 09:17, wrote:
A friend complained of getting a shock from their ancient electric
hob.

Thanks for all the replies everyone.
I must admit, I'm very suspicious of the electrical supply to my
friends flat.
He's on the top floor of a converted house (on the 4th level). The
current installation
is very out-dated and needs modernising. It doesn't even have it's own
consumer
unit, in the flat. Just an old type switch down in the basement
electrical cupboard!

Before putting in the new hob, I also measured the voltage between the
live feed of
the hob supply cable and the earth terminal of the socket outlet, this
measure 240 volts
dead. There was no volts between the neutral and earth supply wires
and the socket
outlet... does this indicate anything?

If there is a possible break in the earth supply to the hob feed, then
I will try running a
'fly lead' straight up from the earth block in the basement, to the
hob and see if that removes
the present voltage leak from the spill rings. I do still wonder
however if this is normal from
the spill rings, as no other part of the hob is emitting voltage.

It's a long way for me to go to the flat, so I want to have a good
idea of the likely cause
before I next go there and try to remedy the fault.

Cheers,
dean.

deano wrote:
On 1 May, 09:17, wrote:

A friend complained of getting a shock from their ancient electric
hob.

Thanks for all the replies everyone.
I must admit, I'm very suspicious of the electrical supply to my
friends flat.
He's on the top floor of a converted house (on the 4th level). The
current installation
is very out-dated and needs modernising. It doesn't even have it's own
consumer
unit, in the flat. Just an old type switch down in the basement
electrical cupboard!

Before putting in the new hob, I also measured the voltage between the
live feed of
the hob supply cable and the earth terminal of the socket outlet, this
measure 240 volts
dead. There was no volts between the neutral and earth supply wires
and the socket
outlet... does this indicate anything?

If there is a possible break in the earth supply to the hob feed, then
I will try running a
'fly lead' straight up from the earth block in the basement, to the
hob and see if that removes
the present voltage leak from the spill rings. I do still wonder
however if this is normal from
the spill rings, as no other part of the hob is emitting voltage.

It's a long way for me to go to the flat, so I want to have a good
idea of the likely cause
before I next go there and try to remedy the fault.

Cheers,
dean.

You've got a missing earth somewhere. The resulting risk varies
from one appliance to another, and is highest for hobs and
showers.

Lack of a CU in the flat, and lack of a CU even in the basement - if
I understand you rightly - makes the odds of a very dodgy
installation high.

I'd start by checking the basics, installation fusing, earthing,
cable
condition etc, and it sounds like the installation would fail even on
that level.

The trouble with unearthed hobs: you're holding boiling water and
frying fat, so even the slightest shock can cause severe burns.
And hobs use heating elements, which are probably the most likely
item to become leaky. And they use water, and a damp
environment increases risks further.

Resolving the worst of the situation would mean finding the supply
feed to the flat and fitting a CU, and checking the earth fed to the
flat. Sounds like there will be other things to sort as well. It
might
be too big a job for you, don't know.


NT

"deano" wrote in message
...
On 1 May, 09:17, wrote:
A friend complained of getting a shock from their ancient electric
hob.

Thanks for all the replies everyone.
I must admit, I'm very suspicious of the electrical supply to my
friends flat.
He's on the top floor of a converted house (on the 4th level). The
current installation
is very out-dated and needs modernising. It doesn't even have it's own
consumer
unit, in the flat. Just an old type switch down in the basement
electrical cupboard!

If this one switch is providing ring main power, cooker supply and lights
all as one big spur then you may have some "issues" (or your friend does).


Before putting in the new hob, I also measured the voltage between the
live feed of
the hob supply cable and the earth terminal of the socket outlet, this
measure 240 volts
dead. There was no volts between the neutral and earth supply wires
and the socket
outlet... does this indicate anything?

That would depend on the earthing arrangements of the supply to the
property - there are many others here wildly more proficient than I at
explaining it!


If there is a possible break in the earth supply to the hob feed, then
I will try running a
'fly lead' straight up from the earth block in the basement, to the
hob and see if that removes
the present voltage leak from the spill rings. I do still wonder
however if this is normal from
the spill rings, as no other part of the hob is emitting voltage.

Nonetheless, the metal parts of the cooker should be earthed so that such
leakages do not manifest themselves as volts. No combination of appliance
and installation should give you a shock, however small. You have replaced
the hob so it cannot be corrosion and no hob would be designed like that.
Providing a second, good earth to the hob to try it out seems the best bet
to proceed with diagnosis

You can only help the situation (or have no affect on it) by installing a
separate earth - whether the whole installation is cr*p or not and whether
or not your earth is untidy!


--
Bob Mannix
(anti-spam is as easy as 1-2-3 - not)

"Gerald Newton" wrote in message
...
On May 1, 12:17 am, wrote:
A friend complained of getting a shock from their ancient electric
hob. This occurred when they grabbed at a metal handled saucepan on
the hob, while touching the stainless steel sink.

I measured 20 volts between the stainless steel 'spill ring' (which
surrounds each of the hob rings) and a known earth (in this case, the
earth terminal of a nearby socket outlet).

Deeming the age of the hob to be a likely suspect, I have since
replaced this with a new hob. However, the voltage issue remains and I
am still getting 20 volts from the new hob's spill rings! I tried
phoning Moffat to see if this is normal, only to be told that they no
longer operate a technical department for dealing with customer
issues, which I find ridiculous.

So, can anyone here offer up any info or advice as to whether this is
normal for an electric hob, or what might be the cause if this
shouldn't be happening?

Many thanks,
Dean.

You are apparently not in the US, if you were I would say the main
bonding jumper is missing, because I had the same thing happen to me
on an inpection job except I laid my metal tablet on the electric
stove and touched it and the metal sink at the same time. A hot wire
was pinched at a pump cover in the basement and the main bonding
jumper was missing so the breakers could not trip. All the water
pipes were at 120 volts, and the stove was grounded using the neutral
so there was 120 volts from the stove to the metal sink.

Nasty! Except here it would be the supply earth was missing, a live wire was
pinched and the RCD's didn't trip as the earth was missing and the pump was
floating (except an RCD might have). All the water pipes would have been at
240V, as would the cooker to the sink. Ah, two nations divided by a common
language ). Still, Volts is volts and missing earth/bonding just as
dangerous either side of the pond.


--
Bob Mannix
(anti-spam is as easy as 1-2-3 - not)