In message , Harry Bloomfield
writes
Tim Lamb was thinking very hard :
And quite right too. The switch contacts are designed to break the
current cleanly. The pin contacts may suffer a series of arcs leading
to pitting and degradation. In the worst case heating such that the
Beryllium copper contacts lose their *spring*.

Were the sockets not designed to break the current, then all sockets
would be fitted with switches.

Worst case is domestic staff switching off kettles by lifting the jug
from the base as you might from a kitchen range!

I do that too. They have a switch in the base to swith the supply when
the kettle is lifted. Even if the base switch does eventually fail, by
then the kettle will need to be replaced. They are not expensive these
days.

I'm not sure if you can purchase an unswitched 13 Amp socket these days
and I think the switch on the kettle base is to protect you from exposed
live connections rather than extend the life of the contacts.

However, as you say, these are throwaway items:-)

--
Tim Lamb

In message , Andy Burns
writes
Harry Bloomfield wrote:

Tim Lamb wrote:

switching off kettles by lifting the jug from the base

They have a switch in the base to swith the supply when
the kettle is lifted.

Perhaps the older "jug" style ones with the connector at the back did
(I haven't got one left to check) but the more common ones now have a
coaxial connector, that's permanently live. Mine has a paddle switch
on the kettle itself, not sure if they all do?

I had a quick look at our *noisiest kettle in the world* and found a
tiny plastic plunger inside the coax assembly which presumably isolates
the contacts and backs up the paddle switch.


--
Tim Lamb

On 01/03/17 08:55, Tim Lamb wrote:
I'm not sure if you can purchase an unswitched 13 Amp socket these days

Don't be silly


http://www.screwfix.com/p/crabtree-1...d-socket/80093
etc.



--
Ideas are more powerful than guns. We would not let our enemies have
guns, why should we let them have ideas?

Josef Stalin

Tim Lamb wrote:

I had a quick look at our *noisiest kettle in the world* and found a
tiny plastic plunger inside the coax assembly which presumably isolates
the contacts and backs up the paddle switch.

I waved a non-contact tester near mine and it lit-up from the centre of
the socket, maybe you could test with a paper clip :-)

The Natural Philosopher wrote:

On 01/03/17 08:55, Tim Lamb wrote:
I'm not sure if you can purchase an unswitched 13 Amp socket these days

Don't be silly


http://www.screwfix.com/p/crabtree-1...d-socket/80093
etc.

I don't think that the existence of unswitched sockets is evidence
either way as to whether it is appropriate to routinely put in and take
out a plug from a live socket. The most common use is as a demountable
permanent connection to an appliance fed from a separate isolating
switch.

--

Roger Hayter

Roger Hayter explained :
I don't think that the existence of unswitched sockets is evidence
either way as to whether it is appropriate to routinely put in and take
out a plug from a live socket. The most common use is as a demountable
permanent connection to an appliance fed from a separate isolating
switch.

We don't routinely pull plugs out to switch things off and most loads
these days are relatively tiny anyway. Probably the most common larger
load to be constantly plugged in and out, is a vacuum cleaner. The
noise alone is enough to make you turn it off at the appliance before
unplugging. Most of the things we have plugged in, stay plugged in for
years.

On Wed, 01 Mar 2017 08:55:45 +0000, Tim Lamb wrote:

In message , Harry Bloomfield
writes
Tim Lamb was thinking very hard :
And quite right too. The switch contacts are designed to break the
current cleanly. The pin contacts may suffer a series of arcs leading
to pitting and degradation. In the worst case heating such that the
Beryllium copper contacts lose their *spring*.

Were the sockets not designed to break the current, then all sockets
would be fitted with switches.

Worst case is domestic staff switching off kettles by lifting the jug
from the base as you might from a kitchen range!

I do that too. They have a switch in the base to swith the supply when
the kettle is lifted. Even if the base switch does eventually fail, by
then the kettle will need to be replaced. They are not expensive these
days.

I'm not sure if you can purchase an unswitched 13 Amp socket these days
and I think the switch on the kettle base is to protect you from exposed
live connections rather than extend the life of the contacts.

https://www.mkelectric.com/en-gb/Pro...socketoutlets/
Pages/K780WHI.aspx


--
My posts are my copyright and if @diy_forums or Home Owners' Hub
wish to copy them they can pay me £1 a message.
Use the BIG mirror service in the UK: http://www.mirrorservice.org
*lightning surge protection* - a w_tom conductor

In article ,
Tim Lamb wrote:
Worst case is domestic staff switching off kettles by lifting the jug
from the base as you might from a kitchen range!

I've been doing that for years if I remove it before it has switched off
automatically. Hasn't done any harm judging by the age of the kettle.

--
*If a pig loses its voice, is it disgruntled?

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

In article ,
Roger Hayter wrote:
I don't think that the existence of unswitched sockets is evidence
either way as to whether it is appropriate to routinely put in and take
out a plug from a live socket. The most common use is as a demountable
permanent connection to an appliance fed from a separate isolating
switch.

Never really saw any point in an unswitched socket - except to save
pennies at the expense of convenience.

--
*Eagles may soar, but weasels don't get sucked into jet engines *

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

In article ,
Harry Bloomfield wrote:
Roger Hayter explained :
I don't think that the existence of unswitched sockets is evidence
either way as to whether it is appropriate to routinely put in and take
out a plug from a live socket. The most common use is as a demountable
permanent connection to an appliance fed from a separate isolating
switch.

We don't routinely pull plugs out to switch things off and most loads
these days are relatively tiny anyway. Probably the most common larger
load to be constantly plugged in and out, is a vacuum cleaner. The
noise alone is enough to make you turn it off at the appliance before
unplugging. Most of the things we have plugged in, stay plugged in for
years.

Trying to think of any high current device that doesn't have a local
switch so you'd always have to plug and unplug 'live' with an unswitched
socket. Some older types of heaters, I suppose. But they would be a real
pain having to unplug to switch them off anyway.

--
*You're just jealous because the voices only talk to me *

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

In article ,
Tim Lamb wrote:
In message , Harry Bloomfield
writes
Tim Lamb was thinking very hard :
And quite right too. The switch contacts are designed to break the
current cleanly. The pin contacts may suffer a series of arcs leading
to pitting and degradation. In the worst case heating such that the
Beryllium copper contacts lose their *spring*.

Were the sockets not designed to break the current, then all sockets
would be fitted with switches.

Worst case is domestic staff switching off kettles by lifting the jug
from the base as you might from a kitchen range!

I do that too. They have a switch in the base to swith the supply when
the kettle is lifted. Even if the base switch does eventually fail, by
then the kettle will need to be replaced. They are not expensive these
days.

I'm not sure if you can purchase an unswitched 13 Amp socket these days

[Snip]

According to TLC's catalogue Contactum make them.

--
from KT24 in Surrey, England

On 01/03/2017 11:17, Dave Plowman (News) wrote:
In article ,
Tim Lamb wrote:
Worst case is domestic staff switching off kettles by lifting the jug
from the base as you might from a kitchen range!

I've been doing that for years if I remove it before it has switched off
automatically. Hasn't done any harm judging by the age of the kettle.

That method disconnects the power in three different ways (switch in
base, paddle switch on kettle, physical disconnection - don't know which
happens first) so why add a fourth? (Though I usually switch off at the
mains afterwards to avoid accidental switching on of an empty kettle.)

--
Max Demian

On Wed, 01 Mar 2017 12:11:16 +0000, charles wrote:

In article ,
Tim Lamb wrote:
In message , Harry Bloomfield
writes
Tim Lamb was thinking very hard :
And quite right too. The switch contacts are designed to break the
current cleanly. The pin contacts may suffer a series of arcs
leading to pitting and degradation. In the worst case heating such
that the Beryllium copper contacts lose their *spring*.

Were the sockets not designed to break the current, then all sockets
would be fitted with switches.

Worst case is domestic staff switching off kettles by lifting the
jug
from the base as you might from a kitchen range!

I do that too. They have a switch in the base to swith the supply when
the kettle is lifted. Even if the base switch does eventually fail, by
then the kettle will need to be replaced. They are not expensive these
days.

I'm not sure if you can purchase an unswitched 13 Amp socket these days

[Snip]

According to TLC's catalogue Contactum make them.

And MK.



--
My posts are my copyright and if @diy_forums or Home Owners' Hub
wish to copy them they can pay me £1 a message.
Use the BIG mirror service in the UK: http://www.mirrorservice.org
*lightning surge protection* - a w_tom conductor

In message , Bob Eager
writes
On Wed, 01 Mar 2017 12:11:16 +0000, charles wrote:

In article ,
Tim Lamb wrote:
In message , Harry Bloomfield
writes
Tim Lamb was thinking very hard :
And quite right too. The switch contacts are designed to break the
current cleanly. The pin contacts may suffer a series of arcs
leading to pitting and degradation. In the worst case heating such
that the Beryllium copper contacts lose their *spring*.

Were the sockets not designed to break the current, then all sockets
would be fitted with switches.

Worst case is domestic staff switching off kettles by lifting the
jug
from the base as you might from a kitchen range!

I do that too. They have a switch in the base to swith the supply when
the kettle is lifted. Even if the base switch does eventually fail, by
then the kettle will need to be replaced. They are not expensive these
days.

I'm not sure if you can purchase an unswitched 13 Amp socket these days

[Snip]

According to TLC's catalogue Contactum make them.

And MK.

OK chaps. You can buy them! Would you?

--
Tim Lamb

On 01/03/17 13:03, Bob Eager wrote:
On Wed, 01 Mar 2017 12:11:16 +0000, charles wrote:

In article ,
Tim Lamb wrote:
In message , Harry Bloomfield
writes
Tim Lamb was thinking very hard :
And quite right too. The switch contacts are designed to break the
current cleanly. The pin contacts may suffer a series of arcs
leading to pitting and degradation. In the worst case heating such
that the Beryllium copper contacts lose their *spring*.

Were the sockets not designed to break the current, then all sockets
would be fitted with switches.

Worst case is domestic staff switching off kettles by lifting the
jug
from the base as you might from a kitchen range!

I do that too. They have a switch in the base to swith the supply when
the kettle is lifted. Even if the base switch does eventually fail, by
then the kettle will need to be replaced. They are not expensive these
days.

I'm not sure if you can purchase an unswitched 13 Amp socket these days

[Snip]

According to TLC's catalogue Contactum make them.

And MK.



and everybody else


--
The theory of Communism may be summed up in one sentence: Abolish all
private property.

Karl Marx

On 01/03/17 14:00, Tim Lamb wrote:
In message , Bob Eager
writes
On Wed, 01 Mar 2017 12:11:16 +0000, charles wrote:

In article ,
Tim Lamb wrote:
In message , Harry Bloomfield
writes
Tim Lamb was thinking very hard :
And quite right too. The switch contacts are designed to break the
current cleanly. The pin contacts may suffer a series of arcs
leading to pitting and degradation. In the worst case heating such
that the Beryllium copper contacts lose their *spring*.

Were the sockets not designed to break the current, then all sockets
would be fitted with switches.

Worst case is domestic staff switching off kettles by lifting the
jug
from the base as you might from a kitchen range!

I do that too. They have a switch in the base to swith the supply when
the kettle is lifted. Even if the base switch does eventually fail, by
then the kettle will need to be replaced. They are not expensive these
days.

I'm not sure if you can purchase an unswitched 13 Amp socket these days

[Snip]

According to TLC's catalogue Contactum make them.

And MK.

OK chaps. You can buy them! Would you?

Oh yes. In some application they are ideal, when you don't want anything
accidentally switched off

Like a washing machine or a fridge
--
Gun Control: The law that ensures that only criminals have guns.

On Wed, 01 Mar 2017 14:00:35 +0000, Tim Lamb wrote:

In message , Bob Eager
writes
On Wed, 01 Mar 2017 12:11:16 +0000, charles wrote:

In article ,
Tim Lamb wrote:
In message , Harry Bloomfield
writes
Tim Lamb was thinking very hard :
And quite right too. The switch contacts are designed to break the
current cleanly. The pin contacts may suffer a series of arcs
leading to pitting and degradation. In the worst case heating such
that the Beryllium copper contacts lose their *spring*.

Were the sockets not designed to break the current, then all sockets
would be fitted with switches.

Worst case is domestic staff switching off kettles by lifting the
jug
from the base as you might from a kitchen range!

I do that too. They have a switch in the base to swith the supply
when the kettle is lifted. Even if the base switch does eventually
fail, by then the kettle will need to be replaced. They are not
expensive these days.

I'm not sure if you can purchase an unswitched 13 Amp socket these
days

[Snip]

According to TLC's catalogue Contactum make them.

And MK.

OK chaps. You can buy them! Would you?

I installed one quite near where I am sitting. It was a very specific
thing; I wanted a socket that could take even large wall warts, for a BT
router (I knew how big it was, and it made the switch inaccessible).
So...single unswitched socket, with adjacent switch.

Same for the under-worktop socket for the dishwasher, with switch above.



--
My posts are my copyright and if @diy_forums or Home Owners' Hub
wish to copy them they can pay me £1 a message.
Use the BIG mirror service in the UK: http://www.mirrorservice.org
*lightning surge protection* - a w_tom conductor

On 01/03/2017 11:19, Dave Plowman (News) wrote:
Never really saw any point in an unswitched socket - except to save
pennies at the expense of convenience.

Well the unswitched socket for our freezer reduces the chance of anyone
inadvertently turning it off.

--
Mike Clarke

On Wed, 1 Mar 2017 09:30:41 +0000, The Natural Philosopher wrote:

On 01/03/17 08:55, Tim Lamb wrote:
I'm not sure if you can purchase an unswitched 13 Amp socket these days

Don't be silly

http://www.screwfix.com/p/crabtree-1...d-socket/80093
etc.

Couple of years ago SF had unswitched MK 13A plates advertised as "double
pole".
--
Peter.
The gods will stay away
whilst religions hold sway

On 2017-02-25, Onetap wrote:

Most probably hydrogen from electolytic/bi-metallic corrosion. That
produces H2 & O2. The oxygen combines with the inside surface of
your radiators to form magnetite sludge. Igniting it at the air
vent is most unlikely to cause an explosion (I've never heard of
that happening), but the recommended procedure is to bleed the
gas into an upturned glass/bottle (H2 floats upwards) and then
ignite that. You may otherwise have difficulty in closing the air
vent after it has turned into a blow-torch (see Youtube).

If hydrogen, the gas in the upturned glass will light with a pop and burn upwards.

It does ignite. (Someone else mentioned hydrogen sulphide, but
there's no eggy smell. Once the gas is all out & water starts to
squirt, there's a non-eggy "chemical" smell, which I assume is the
inhibitor.)

How much do I need to worry about this, & what should I ask the
plumbers to do? (The boiler is due for an annual service in 2 months
anyway.)


The important thing is that you'll usually only get the
electrolytic/bi-metallic corrosion if the water is acidic. The
acid usually gets in to the system as the residues from active
flux (contains ammonium chloride, forms HCl on heating ISTR) that
hasn't been thoroughly flushed out.

The French braze copper heating pipes (no flux needed); they have
virtually no black sludge problems, there is no market for
power-flushing in France. Go figure.

It's been power-flushed. They will have used an acidic cleaner
(HCl); that has to be flushed, neutralized (with caustic soda),
flushed, checked with litmus paper (did you see that done?) and
flushed again for good measure.

The power-flushing was several years ago. The air (not really air, as
we've established) seems to more common now than it was.

It might be air (nitrogen); that can get drawn into the system on
the suction side of the pump, as mentioned elsewhere. The oxygen
forms magnetite, as above. The expansion vessel connection
(neutral point, PONPC) should be on the pump inlet side.

Most good domestic inhibitors (Sentinel, Fernox, etc) contain sodium
molybdate; ISTR that the mixture is slightly acidic. I like to
run a flushed system with clean water for a few hours, check it's
not acidic, then add inhibitor.

If it's acidic water that causes/allows the problem, why are good
inhibitors slightly acidic?

On 2017-03-08, Adam Funk wrote:

On 2017-02-25, Onetap wrote:

Most probably hydrogen from electolytic/bi-metallic corrosion. That
produces H2 & O2. The oxygen combines with the inside surface of
your radiators to form magnetite sludge. Igniting it at the air
vent is most unlikely to cause an explosion (I've never heard of
that happening), but the recommended procedure is to bleed the
gas into an upturned glass/bottle (H2 floats upwards) and then
ignite that. You may otherwise have difficulty in closing the air
vent after it has turned into a blow-torch (see Youtube).

If hydrogen, the gas in the upturned glass will light with a pop and burn upwards.

It does ignite. (Someone else mentioned hydrogen sulphide, but
there's no eggy smell. Once the gas is all out & water starts to
squirt, there's a non-eggy "chemical" smell, which I assume is the
inhibitor.)

How much do I need to worry about this, & what should I ask the
plumbers to do? (The boiler is due for an annual service in 2 months
anyway.)

BTW, I just drew a small sample from the drain at the bottom of the
heating system: the water looked clean, had the same non-eggy chemical
smell, & had a pH of 7 to 8.