When I switch my kettle off at the electric socket, a brief flash of
green light is visible behind the socket. Is this normal, or could it
be dangerous? Supposedly it's ok if the kettle plug is earthed?

Adam.

On 2/26/2009 11:06 AM Hobbyist spake thus:

When I switch my kettle off at the electric socket, a brief flash of
green light is visible behind the socket. Is this normal, or could it
be dangerous? Supposedly it's ok if the kettle plug is earthed?

Flashes of light accompanying switching something on or off are *never*
OK. Indicates arcing contacts, which can only get worse with time.

Not sure where or what kind of switch you have; "switch my kettle off at
the electric socket" is a bit ambiguous. But it's time to replace that
switch if it sparks. "Earthing" (aka grounding) won't help you here.


--
Personally, I like Vista, but I probably won't use it. I like it
because it generates considerable business for me in consulting and
upgrades. As long as there is hardware and software out there that
doesn't work, I stay in business. Incidentally, my company motto is
"If this stuff worked, you wouldn't need me".

- lifted from sci.electronics.repair

David Nebenzahl wrote:

On 2/26/2009 11:06 AM Hobbyist spake thus:

When I switch my kettle off at the electric socket, a brief flash of
green light is visible behind the socket. Is this normal, or could it
be dangerous? Supposedly it's ok if the kettle plug is earthed?

Flashes of light accompanying switching something on or off are *never*
OK. Indicates arcing contacts, which can only get worse with time.

Not sure where or what kind of switch you have; "switch my kettle off at
the electric socket" is a bit ambiguous. But it's time to replace that
switch if it sparks. "Earthing" (aka grounding) won't help you here.

Thanks, David. I'll call an electrician, and meantime I'll use a
different socket (with on/switch on the socket - when it's on, you see
the part of the switch that is painted red, otherwise it's white when
pressed the other way - not sure if that explains it. I'm in
England).

Adam.

Hobbyist asked:

When I switch my kettle off at the
electric socket, a brief flash of green
light is visible behind the socket. Is this
normal, or could it be dangerous?

It sounds like there is a loose connection to the socket. I suggest you
have it checked before you have a fire.


---MIKE---
In the White Mountains of New Hampshire
(44° 15' N - Elevation 1580')

On 2/26/2009 11:43 AM Hobbyist spake thus:

David Nebenzahl wrote:

On 2/26/2009 11:06 AM Hobbyist spake thus:

When I switch my kettle off at the electric socket, a brief flash of
green light is visible behind the socket. Is this normal, or could it
be dangerous? Supposedly it's ok if the kettle plug is earthed?

Flashes of light accompanying switching something on or off are *never*
OK. Indicates arcing contacts, which can only get worse with time.

Not sure where or what kind of switch you have; "switch my kettle off at
the electric socket" is a bit ambiguous. But it's time to replace that
switch if it sparks. "Earthing" (aka grounding) won't help you here.

Thanks, David. I'll call an electrician, and meantime I'll use a
different socket (with on/switch on the socket - when it's on, you see
the part of the switch that is painted red, otherwise it's white when
pressed the other way - not sure if that explains it. I'm in
England).

So it's a receptacle with a switch inbuilt, right? Should be easy to
replace.


--
Personally, I like Vista, but I probably won't use it. I like it
because it generates considerable business for me in consulting and
upgrades. As long as there is hardware and software out there that
doesn't work, I stay in business. Incidentally, my company motto is
"If this stuff worked, you wouldn't need me".

- lifted from sci.electronics.repair

---MIKE--- wrote:

Hobbyist asked:

When I switch my kettle off at the
electric socket, a brief flash of green
light is visible behind the socket. Is this
normal, or could it be dangerous?

It sounds like there is a loose connection to the socket. I suggest you
have it checked before you have a fire.

Thanks for your advice, Mike. Had a minor fire a few years back,
caused by lightning, so I don't want another. I'm definitely calling
that electrician.

David Nebenzahl wrote:
On 2/26/2009 11:06 AM Hobbyist spake thus:

When I switch my kettle off at the electric socket, a brief flash of
green light is visible behind the socket. Is this normal, or could it
be dangerous? Supposedly it's ok if the kettle plug is earthed?


Flashes of light accompanying switching something on or off are *never*
OK. Indicates arcing contacts, which can only get worse with time.

So, I'm using one of these Intermatic timers ahead of my home Bunn
coffee maker to remove power from it during the night. That saves us a
little electricity by not keep the water at brewing temperature all the
time.

http://www.intermatic.com/images/misc/TN111C.pdf

The Bunn is rated as drawing 900 watts and the timer is rated to switch
1750 watts resistive, almost twice as much as the resistive heaters in
the Bunn consume.

If I turn the timer dial by hand, when it switches power off I can see a
small spark through the opening the overide control knob protrudes through.

Yet, you say such flashes are *never* OK.

I don't agree. Have you ever closely watched the contacts of a relay
controlling a few hundred watts of load? When the contacts open there is
almost always a small visible spark.

I agree with you that arcing contacts will only get worse with time, but
sometimes there's no easy way to eliminate that arcing, and that "time"
can often be measured in years. That's why we had to change out the
distributor points in our cars when they got blown away by the sparks
occuring every time they switched.

But, that was before they started using solid state switching for that
job, wasn't it?

Jeff
--
Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
The speed of light is 1.8*10^12 furlongs per fortnight.

Not sure where or what kind of switch you have; "switch my kettle off at
the electric socket" is a bit ambiguous. But it's time to replace that
switch if it sparks. "Earthing" (aka grounding) won't help you here.

"Hobbyist" wrote in message
...
When I switch my kettle off at the electric socket, a brief flash of
green light is visible behind the socket. Is this normal, or could it
be dangerous? Supposedly it's ok if the kettle plug is earthed?

Adam.

Any time a switch makes or breaks a contact while under a load, it will
cause an arc. Typically you can't see it, because it's enclosed inside the
device, but it exists and is perfectly normal. That being said, there could
still be something wrong with the device or the connection, so having a
professional look at it is a good idea

On 2/26/2009 1:10 PM Jeff Wisnia spake thus:

David Nebenzahl wrote:

On 2/26/2009 11:06 AM Hobbyist spake thus:

When I switch my kettle off at the electric socket, a brief flash of
green light is visible behind the socket. Is this normal, or could it
be dangerous? Supposedly it's ok if the kettle plug is earthed?

Flashes of light accompanying switching something on or off are *never*
OK. Indicates arcing contacts, which can only get worse with time.

So, I'm using one of these Intermatic timers ahead of my home Bunn
coffee maker to remove power from it during the night. That saves us a
little electricity by not keep the water at brewing temperature all the
time.

http://www.intermatic.com/images/misc/TN111C.pdf

The Bunn is rated as drawing 900 watts and the timer is rated to switch
1750 watts resistive, almost twice as much as the resistive heaters in
the Bunn consume.

If I turn the timer dial by hand, when it switches power off I can see a
small spark through the opening the overide control knob protrudes through.

Yet, you say such flashes are *never* OK.

I don't agree. Have you ever closely watched the contacts of a relay
controlling a few hundred watts of load? When the contacts open there is
almost always a small visible spark.

Point taken; I guess it's a matter of degree. Some sparking with relay
contacts switching a large load are, as you say, normal. I think the
green sparks the O.P. saw were a little more dangerous. Hard to say
exactly where to draw the line; I'd say if there's a significant amount
of sputtering or sizzling sounds emanating from the device, it's not good.


--
Personally, I like Vista, but I probably won't use it. I like it
because it generates considerable business for me in consulting and
upgrades. As long as there is hardware and software out there that
doesn't work, I stay in business. Incidentally, my company motto is
"If this stuff worked, you wouldn't need me".

- lifted from sci.electronics.repair

RBM wrote:
"Hobbyist" wrote in message
...
When I switch my kettle off at the electric socket, a brief flash of
green light is visible behind the socket. Is this normal, or could it
be dangerous? Supposedly it's ok if the kettle plug is earthed?

Adam.

Any time a switch makes or breaks a contact while under a load, it will
cause an arc. Typically you can't see it, because it's enclosed inside the
device, but it exists and is perfectly normal. That being said, there could
still be something wrong with the device or the connection, so having a
professional look at it is a good idea

I believe kettles are relatively high watt loads. And with 230V the arc
may be larger. Could be entirely normal. Or possibly not.

A better place to ask the question is probably
uk.d-i-y
Last I saw it was a very active newsgroup and handled UK electrical
questions. This newsgroup is primarily US and Canada. It is really
surprising how much different the electrical practice in the UK is. For
instance sockets do not have switches this side the pond. And we do not
have 32A general use branch circuits and never ring circuits.

--
bud--

David Nebenzahl wrote:
On 2/27/2009 7:15 AM bud-- spake thus:

A better place to ask the question is probably
uk.d-i-y

Ackshooly, the OP seems to have gotten good answers here.

Last I saw it was a very active newsgroup and handled UK electrical
questions. This newsgroup is primarily US and Canada. It is really
surprising how much different the electrical practice in the UK is.
For instance sockets do not have switches this side the pond. And we
do not have 32A general use branch circuits and never ring circuits.

Well, we (North America) *can* have switched sockets; the devices are
available, and I've seen them in homes, even installed them myself, but
it's true they're not common. And yes, no 32 A (!!!) branch circuits and
the exceedingly *weird* ring circuits. Leave it to the Brits ...

However, I will say that 230/240 volts is more efficient than our 120.
(Less I^^2 R loss.)



Except they have 50 cycle power. Bigger transformers needed.

TDD

Hobbyist wrote:
When I switch my kettle off at the electric socket, a brief flash of
green light is visible behind the socket. Is this normal, or could it
be dangerous? Supposedly it's ok if the kettle plug is earthed?

Adam.

A flash from a switch is normal, especially if it
is switching a load. If yours had a sustained arc,
that would be something to worry about. I have
increased the life of switches and other contacts
by using diodes, resistors, capacitors or MOV's to
suppress the arc. I have an adorable little electric
kettle that draws 800 watts at 120 volts AC. Of course
we colonial Hillbillies drink ice tea. *snicker*

http://www.industrologic.com/mechrela.htm

TDD

On 2/27/2009 6:31 PM The Daring Dufas spake thus:

David Nebenzahl wrote:

However, I will say that 230/240 volts is more efficient than our 120.
(Less I^^2 R loss.)

Except they have 50 cycle power. Bigger transformers needed.

Surely not by much, though.


--
Personally, I like Vista, but I probably won't use it. I like it
because it generates considerable business for me in consulting and
upgrades. As long as there is hardware and software out there that
doesn't work, I stay in business. Incidentally, my company motto is
"If this stuff worked, you wouldn't need me".

- lifted from sci.electronics.repair

David Nebenzahl wrote:
On 2/27/2009 6:31 PM The Daring Dufas spake thus:

David Nebenzahl wrote:

However, I will say that 230/240 volts is more efficient than our
120. (Less I^^2 R loss.)

Except they have 50 cycle power. Bigger transformers needed.

Surely not by much, though.



Have you ever seen the transformers used in 400 cycle AC systems?
They're tiny things used mostly in aircraft power systems.

TDD