I recently bought an electric heater from argos. It is working ok but
when switched on/off at the wall socket sometimes a spark is seen
inside the socket. The house was re-wired a couple of years ago and is
all properly fused etc.

Is this normal behavior for an electric heater / does it indicate a
fault and should be replaced?

In article ,
writes:
I recently bought an electric heater from argos. It is working ok but
when switched on/off at the wall socket sometimes a spark is seen
inside the socket. The house was re-wired a couple of years ago and is
all properly fused etc.

Is this normal behavior for an electric heater / does it indicate a
fault and should be replaced?

It's normal for a high power load, providing it's only whilst you
are moving the switch. If the plug or socket gets hot or has any
discolouration caused by having got hot, that needs invesigating.
If it's a 3kW heater, the plug fuse is expected to get warm though.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

On Fri, 5 Dec 2008 02:59:46 -0800 (PST),
wrote:

Is this normal behavior for an electric heater / does it indicate a
fault and should be replaced?

Is the heater on or off when you switch it off at the socket?

--
Cheers
Dave.

On Fri, 5 Dec 2008 02:59:46 -0800 (PST),
wrote:

I recently bought an electric heater from argos. It is working ok but
when switched on/off at the wall socket sometimes a spark is seen
inside the socket. The house was re-wired a couple of years ago and is
all properly fused etc.

Is this normal behavior for an electric heater / does it indicate a
fault and should be replaced?

How can you see a spark inside the socket when you switch off the
socket or do you mean you can see the spark inside the unused half of
a double socket or are you just pulling the plug out with the socket
switch in the ON position?

On 5 Dec, 13:10, "Dave Liquorice"
wrote:
On Fri, 5 Dec 2008 02:59:46 -0800 (PST),
wrote:

Is this normal behavior for an electric heater / does it indicate a
fault and should be replaced?

Is the heater on or off when you switch it off at the socket?

--
Cheers
Dave.

The heater is on. I usually just turn it on/off at the wall. Is this
inadvisable?

On 5 Dec, 13:52, wrote:
On Fri, 5 Dec 2008 02:59:46 -0800 (PST),
wrote:

I recently bought an electric heater from argos. It is working ok but
when switched on/off at the wall socket sometimes a spark is seen
inside the socket. The house was re-wired a couple of years ago and is
all properly fused etc.

Is this normal behavior for an electric heater / does it indicate a
fault and should be replaced?

How can you see a spark inside the socket when you switch off the
socket or do you mean you can see the spark inside the unused half of
a double socket or are you just pulling the plug out with the socket
switch in the ON position? *

I see a light through the plastic socket cover and sometimes see the
spark through the gap the switch sits in.

On Fri, 5 Dec 2008 05:58:22 -0800 (PST),
wrote:

The heater is on. I usually just turn it on/off at the wall. Is this
inadvisable?

In a word yes. B-) Not overly important for small loads but heavy ones
like heaters it is better to switch off on the appliance before switching
off at the wall. If nothing else it saves damage to the sockets switching
contacts by the arc that you see.

--
Cheers
Dave.

On Fri, 5 Dec 2008 05:59:09 -0800 (PST) someone who may be
wrote this:-

I see a light through the plastic socket cover and sometimes see the
spark through the gap the switch sits in.

What is the rating of this fire. 3kW?

With any reasonably high power electrical equipment there will often
be a visible spark at the switchgear when it is switched off [1]
[2]. This is generally nothing to worry about. However, if the
heater has its own controls I suggest using them to switch the
heater on and off. The spark will still be there, but it may not be
visible (sometimes it is more visible in a heater though, there is
not one answer to your questions).

The sparks (and arcs) on large switchgear can be very impressive
indeed, there are films on the web.

[1] with AC electricity there are times when the current is so close
to zero that there is no spark. Whether you operate the switch at
that time is a matter of luck.

[2] the spark is often still there even if it is not visible.


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

wrote:
I recently bought an electric heater from argos. It is working ok but
when switched on/off at the wall socket sometimes a spark is seen
inside the socket. The house was re-wired a couple of years ago and is
all properly fused etc.

Is this normal behavior for an electric heater / does it indicate a
fault and should be replaced?

As long as it isn't as bad as this one, then I think you will be OK.
http://uk.youtube.com/watch?v=iy47NzfCc20

But you should really switch the heater off on the heater first.

Toby...

"Toby" wrote in message
...
wrote:
I recently bought an electric heater from argos. It is working ok but
when switched on/off at the wall socket sometimes a spark is seen
inside the socket. The house was re-wired a couple of years ago and is
all properly fused etc.

Is this normal behavior for an electric heater / does it indicate a
fault and should be replaced?

As long as it isn't as bad as this one, then I think you will be OK.
http://uk.youtube.com/watch?v=iy47NzfCc20

But you should really switch the heater off on the heater first.

Toby...


Is this guy cutting or crimping?
http://uk.youtube.com/watch?v=MH1_gjPTMIg&NR=1

Dave Liquorice wrote:

In a word yes. *B-) *Not overly important for small loads but heavy ones
like heaters it is better to switch off on the appliance before switching
off at the wall. If nothing else it saves damage to the sockets switching
contacts by the arc that you see.

I suppose that would be the case if the switch in the heater were more
durable than the one in the socket. On the other hand a 13A socket is
fairly cheap and easy to replace but sourcing a replacement switch for a
heater could be more difficult, or even impossible for some Chinese
imports.

--
Mike Clarke

"Mike Clarke" wrote in message
et...
Dave Liquorice wrote:

In a word yes. B-) Not overly important for small loads but heavy ones
like heaters it is better to switch off on the appliance before
switching
off at the wall. If nothing else it saves damage to the sockets
switching
contacts by the arc that you see.

I suppose that would be the case if the switch in the heater were more
durable than the one in the socket. On the other hand a 13A socket is
fairly cheap and easy to replace but sourcing a replacement switch for a
heater could be more difficult, or even impossible for some Chinese
imports.

Mike Clarke


There again, the heater switch gear may have been designed to withstand the
arcing caused by switching off the heater element. Back EMF currents, even
from a loosely coiled heater element, can cause higher amperage arcing
across switch gear when the blades are snapped open, which the heater
designer should account for when choosing the materials before equipment
manufacture. I don't think anyone would recommend a heater that flashed
blue and yellow sparks when they used it.

But, we all know that the 13 amp sockets in our houses are designed to
withstand a minimum of 20 amps across the terminals and switching
mechanisms, so it should be capable of accepting the load the heater draws,
but its switching gear may not be able to handle the back EMF current.
Especially if it is one of the cheaper brands which use minimal materials
constructions to keep manufacturing costs down. And it is a pain in the
rear orifice to keep swapping out the sockets in our houses.

On Fri, 05 Dec 2008 23:23:35 +0000, Mike Clarke wrote:

If nothing else it saves damage to the sockets switching contacts by
the arc that you see.

I suppose that would be the case if the switch in the heater were more
durable than the one in the socket. On the other hand a 13A socket is
fairly cheap and easy to replace but sourcing a replacement switch for a
heater could be more difficult, or even impossible for some Chinese
imports.

True enough but I'd rather the switch in the appliance failed rather than
hidden damage in a socket that could go undetected for years until the
contact resistance goes up, a different heavy load is used, the contacts
overheat resulting in a fire... Small risk but still a risk.

--
Cheers
Dave.

On Fri, 05 Dec 2008 23:44:10 GMT, "BigWallop"
wrote:



There again, the heater switch gear may have been designed to withstand the
arcing caused by switching off the heater element. Back EMF currents, even
from a loosely coiled heater element,

Do you have a Bovine Scatter diagram for that ?

can cause higher amperage arcing
across switch gear when the blades are snapped open, which the heater
designer should account for when choosing the materials before equipment
manufacture. I don't think anyone would recommend a heater that flashed
blue and yellow sparks when they used it.


Heating appliances are available in the supermarkets for less than
four quid delivered from China, and the supermarket has made it's
profit as well. How much do you think they've spent on the design and
construction of the mains switch ?

But, we all know that the 13 amp sockets in our houses are designed to
withstand a minimum of 20 amps across the terminals and switching
mechanisms, so it should be capable of accepting the load the heater draws,
but its switching gear may not be able to handle the back EMF current.
Especially if it is one of the cheaper brands which use minimal materials
constructions to keep manufacturing costs down. And it is a pain in the
rear orifice to keep swapping out the sockets in our houses.

writes:

On Fri, 5 Dec 2008 02:59:46 -0800 (PST),
wrote:

I recently bought an electric heater from argos. It is working ok but
when switched on/off at the wall socket sometimes a spark is seen
inside the socket.

How can you see a spark inside the socket when you switch off the
socket

The light from an arc like that is really very bright,
easily bright enough to see through the plastic of a typical
socket.

A few years ago one of the cats in the house where I was
living "sprayed" on the wall above an electrical socket and
it ran down the wall into the pattress box. I didn't see
him do it and he had moved on before I noticed anything, but
I heard a peculiar hissing noise and when I turned round I
could see light shining from the socket -- through the face,
off to one side of the holes -- and quite bright despite
having passed through the plastic. It gave me quite a
fright! And the smell of hot electrolysed cat **** is,
shall we say, distinctive.

--
Jón Fairbairn
http://www.chaos.org.uk/~jf/Stuff-I-dont-want.html (updated 2008-04-26)

Dave Liquorice wrote:
On Fri, 05 Dec 2008 23:23:35 +0000, Mike Clarke wrote:

If nothing else it saves damage to the sockets switching contacts by
the arc that you see.
I suppose that would be the case if the switch in the heater were more
durable than the one in the socket. On the other hand a 13A socket is
fairly cheap and easy to replace but sourcing a replacement switch for a
heater could be more difficult, or even impossible for some Chinese
imports.

True enough but I'd rather the switch in the appliance failed rather than
hidden damage in a socket that could go undetected for years until the
contact resistance goes up, a different heavy load is used, the contacts
overheat resulting in a fire... Small risk but still a risk.


And if you have unswitched sockets, then you would only have the choice
of the applicance switch(es) or pulling it out while running. At four
quid (that *is* cheap), it is probably more sensible to blow the
appliance switch than a socket.

--
Rod

Hypothyroidism is a seriously debilitating condition with an insidious
onset.
Although common it frequently goes undiagnosed.
www.thyromind.info www.thyroiduk.org www.altsupportthyroid.org