..so,for the first 2 years,my comet kiln worked perfectly...then the socket
burnt out,replaced it(always ised a professional electrician)thos time,socket
switches got hardrr and harder to switch on,then the socket stopped working
again,replaced the whole unit...now its happened again...the socket is about
20 ft via armoured cable to the house,the kiln room isnt damp...the kilns
fine,but the plug gets a bit hot(when it worked)the electrician seems to be
baffled...'must be your kiln'...but i know nothing about electrics so cant
argue the toss!can ANYONE help...its driving me mad....

--
for full context, visit https://www.homeownershub.com/uk-diy...s-1287410-.htm

On Tue, 15 May 2018 03:14:02 GMT, Lea Goldberg
m wrote:

.so,for the first 2 years,my comet kiln worked perfectly...then the socket
burnt out,replaced it(always ised a professional electrician)thos time,socket
switches got hardrr and harder to switch on,then the socket stopped working
again,replaced the whole unit...now its happened again...the socket is about
20 ft via armoured cable to the house,the kiln room isnt damp...the kilns
fine,but the plug gets a bit hot(when it worked)the electrician seems to be
baffled...'must be your kiln'...but i know nothing about electrics so cant
argue the toss!can ANYONE help...its driving me mad....

Well if it baffled your professional electrician, there's your
problem.

What subnormal idiot thought that a damp kiln room could have any
bearing on socket condition/ temperature 20 feet away?

AB

On 15/05/2018 06:24, Archibald Tarquin Blenkinsopp wrote:
On Tue, 15 May 2018 03:14:02 GMT, Lea Goldberg
m wrote:

.so,for the first 2 years,my comet kiln worked perfectly...then the socket
burnt out,replaced it(always ised a professional electrician)thos time,socket
switches got hardrr and harder to switch on,then the socket stopped working
again,replaced the whole unit...now its happened again...the socket is about
20 ft via armoured cable to the house,the kiln room isnt damp...the kilns
fine,but the plug gets a bit hot(when it worked)the electrician seems to be
baffled...'must be your kiln'...but i know nothing about electrics so cant
argue the toss!can ANYONE help...its driving me mad....

Well if it baffled your professional electrician, there's your
problem.

What subnormal idiot thought that a damp kiln room could have any
bearing on socket condition/ temperature 20 feet away?


And just because a professional electrician was used it doesn't mean
that the socket wasn't replaced by the cheapest he could source rather
than the best quality available.

A plug/socket getting hot is a sign of inadequate low resistance
connection or it being under-rated.

What socket are you writing about. A standard 13A socket/plug? (Although
I can't see how you would fit a plug to an amoured cable). Is the switch
heavy duty as used for a electric oven?


--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk

There appears to be two versions of the Comet Kiln, the ECO which draws 3kW which should be fine using a 13A plug in a standard socket. The other is a 5.5kW model for which a plug and socket is totally inadequate. There should be a ratings plate somewhere on the kiln check the wattage, although I would have thought your professional electrician would have checked that first.

On 15/05/2018 07:57, Tricky Dicky wrote:
There appears to be two versions of the Comet Kiln, the ECO which draws 3kW which should be fine using a 13A plug in a standard socket. The other is a 5.5kW model for which a plug and socket is totally inadequate. There should be a ratings plate somewhere on the kiln check the wattage, although I would have thought your professional electrician would have checked that first.

Richard

Good point.

The other thing I would suggest even for the 3 kW model is to get your
sparks to fit a "cooker" type breaker switch and then an industrial type
plug and socket like this:

https://uk.rs-online.com/web/p/produ...E&gclsrc=aw.ds

(This is what I did in a friend's business unit after he was getting
short life even from MK plugs and sockets that were running with a high
duty factor).

---
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On 15/05/2018 08:29, newshound wrote:
On 15/05/2018 07:57, Tricky Dicky wrote:
There appears to be two versions of the Comet Kiln, the ECO which
draws 3kW which should be fine using a 13A plug in a standard socket.
The other is a 5.5kW model for which a plug and socket is totally
inadequate. There should be a ratings plate somewhere on the kiln
check the wattage, although I would have thought your professional
electrician would have checked that first.

Richard

Good point.

The other thing I would suggest even for the 3 kW model is to get your
sparks to fit a "cooker" type breaker switch and then an industrial type
plug and socket like this:

https://uk.rs-online.com/web/p/produ...E&gclsrc=aw.ds


(This is what I did in a friend's business unit after he was getting
short life even from MK plugs and sockets that were running with a high
duty factor).

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus


Or wire it straight in - as you would do with a cooker.
My big glass-fusing kiln (7kw or thereabouts) has its own cable straight
back to the consumer unit, a big isolating switch on the workshop wall,
and the same 'big cable' wired direct into the contactors.

Kilns and standard plug-type connectors don't mix - and, as they're
often left running, unattended - it's worthwhile doing the job properly
and safely.

alan_m wrote:

On 15/05/2018 06:24, Archibald Tarquin Blenkinsopp wrote:
On Tue, 15 May 2018 03:14:02 GMT, Lea Goldberg
m wrote:

.so,for the first 2 years,my comet kiln worked perfectly...then the
socket burnt out,replaced it(always ised a professional
electrician)thos time,socket switches got hardrr and harder to switch
on,then the socket stopped working again,replaced the whole unit...now
its happened again...the socket is about 20 ft via armoured cable to
the house,the kiln room isnt damp...the kilns fine,but the plug gets a
bit hot(when it worked)the electrician seems to be baffled...'must be
your kiln'...but i know nothing about electrics so cant argue the
toss!can ANYONE help...its driving me mad....

Well if it baffled your professional electrician, there's your
problem.

What subnormal idiot thought that a damp kiln room could have any
bearing on socket condition/ temperature 20 feet away?


And just because a professional electrician was used it doesn't mean
that the socket wasn't replaced by the cheapest he could source rather
than the best quality available.

A plug/socket getting hot is a sign of inadequate low resistance
connection or it being under-rated.

What socket are you writing about. A standard 13A socket/plug? (Although
I can't see how you would fit a plug to an amoured cable). Is the switch
heavy duty as used for a electric oven?

I assume the 20ft cable is from the house supply to the socket in the
kiln room - and therefore almost certainly irrelevant to the problem.
Why not wire the kiln directly into a fused connection box with an two
pole switch? The socket is failing either because it and/or the plug
are cheap and nasty, or because of pervasive damp and corrosion.



--

Roger Hayter

newshound wrote:

On 15/05/2018 07:57, Tricky Dicky wrote:
There appears to be two versions of the Comet Kiln, the ECO which draws
3kW which should be fine using a 13A plug in a standard socket. The
other is a 5.5kW model for which a plug and socket is totally
inadequate. There should be a ratings plate somewhere on the kiln check
the wattage, although I would have thought your professional electrician
would have checked that first.

Richard

Good point.

The other thing I would suggest even for the 3 kW model is to get your
sparks to fit a "cooker" type breaker switch and then an industrial type
plug and socket like this:


https://uk.rs-online.com/web/p/produ...e=Y&cm_mmc=UK-
PLA-DS3A-_-google-_-PLA_UK_EN_Connectors-_-Power_Connectors%7CIndustrial
_Power_Connectors-_-PRODUCT+GROUP&matchtype=&gclid=EAIaIQobChMIja_et5i H2
wIVWc-yCh0b5AUTEAYYASABEgI9d_D_BwE&gclsrc=aw.ds

(This is what I did in a friend's business unit after he was getting
short life even from MK plugs and sockets that were running with a high
duty factor).

---
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Probably a good idea, but why does he need a plug and socket for the
kiln anyway?

--

Roger Hayter

Its quite obvious that something in that circuit is underrated for the
current being drawn, and once some plastic bit starts to melt you get poor
and poorer contact, even arcing in the end, completely trashing the socket.
If a plug is getting warm that is a good bit of diagnostic help. The pin
that is getting hot is obviously doing so due to underrated connections.
Look in the plug or whatever it is that plugs into the socket which gets
damaged. it is entirely possible that the body of the plug is unaffected if
its a higher melting point plastic.
I had an issue like this with one of those so called plug in mechanical
timers, the one where you put pins in holes. When I opened it up the short
bit of brass from the live pin to the switch had been riveted to either end
and this had oxidised and heated up the pin as a result. Load of rubbish.
I only had a 3K fan heater on it!
Brian

--
----- -
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please!
"Archibald Tarquin Blenkinsopp" wrote in
message ...
On Tue, 15 May 2018 03:14:02 GMT, Lea Goldberg
m wrote:

.so,for the first 2 years,my comet kiln worked perfectly...then the
socket
burnt out,replaced it(always ised a professional electrician)thos
time,socket
switches got hardrr and harder to switch on,then the socket stopped
working
again,replaced the whole unit...now its happened again...the socket is
about
20 ft via armoured cable to the house,the kiln room isnt damp...the kilns
fine,but the plug gets a bit hot(when it worked)the electrician seems to
be
baffled...'must be your kiln'...but i know nothing about electrics so cant
argue the toss!can ANYONE help...its driving me mad....

Well if it baffled your professional electrician, there's your
problem.

What subnormal idiot thought that a damp kiln room could have any
bearing on socket condition/ temperature 20 feet away?

AB

On 15/05/2018 08:39, Adrian Brentnall wrote:
On 15/05/2018 08:29, newshound wrote:
On 15/05/2018 07:57, Tricky Dicky wrote:
There appears to be two versions of the Comet Kiln, the ECO which
draws 3kW which should be fine using a 13A plug in a standard socket.
The other is a 5.5kW model for which a plug and socket is totally
inadequate. There should be a ratings plate somewhere on the kiln
check the wattage, although I would have thought your professional
electrician would have checked that first.

Richard

Good point.

The other thing I would suggest even for the 3 kW model is to get your
sparks to fit a "cooker" type breaker switch and then an industrial
type plug and socket like this:

https://uk.rs-online.com/web/p/produ...E&gclsrc=aw.ds


(This is what I did in a friend's business unit after he was getting
short life even from MK plugs and sockets that were running with a
high duty factor).

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus


Or wire it straight in - as you would do with a cooker.
My big glass-fusing kiln (7kw or thereabouts) has its own cable straight
back to the consumer unit, a big isolating switch on the workshop wall,
and the same 'big cable' wired direct into the contactors.

Kilns and standard plug-type connectors don't mix - and, as they're
often left running, unattended - it's worthwhile doing the job properly
and safely.

Yes, good point about wiring in direct. I used plugs and sockets for my
friend because they are in heater supplies switched by temperature
controllers. This way, if either a heater or a controller fails, working
items can be switched over to a spare device.

But perhaps worth remembering if you have something more portable like a
big welder, which you might want to put away.

newshound was thinking very hard :
Yes, good point about wiring in direct. I used plugs and sockets for my
friend because they are in heater supplies switched by temperature
controllers. This way, if either a heater or a controller fails, working
items can be switched over to a spare device.

Your first step, ought to be to check the actual current drawn or check
the rating plate on the back of the kiln. If it is just over the 13
amps, likely it would not blow the plug top fuse, but damage the plug
and socket over time.

One solution for the 'just over 13amps' is to swap the plug and socket
for a 16amp blue plug and socket. These are unfused, so the MCB would
need to be changed if necessary for a 16amp if it is not already a
16amp.

On 15/05/2018 08:39, Adrian Brentnall wrote:
snip

Kilns and standard plug-type connectors don't mix - and, as they're
often left running, unattended - it's worthwhile doing the job properly
and safely.


And the OP may need to watch the implications for her insurance of
anything which departs from the regs/manufacturer's requirements. And
double and redouble that if she is using it commercially and has
employees who use or are around the kiln, run courses where people use
it, ...


--
Robin
reply-to address is (intended to be) valid

In article ,
Lea Goldberg m wrote:
.so,for the first 2 years,my comet kiln worked perfectly...then the
socket burnt out,replaced it(always ised a professional electrician)thos
time,socket switches got hardrr and harder to switch on,then the socket
stopped working again,replaced the whole unit...now its happened
again...the socket is about 20 ft via armoured cable to the house,the
kiln room isnt damp...the kilns fine,but the plug gets a bit hot(when it
worked)the electrician seems to be baffled...'must be your kiln'...but i
know nothing about electrics so cant argue the toss!can ANYONE
help...its driving me mad....

Despite being rated at 13 amps, most sockets and plugs aren't happy to
carry that for very long periods. They are a domestic connector and really
for intermittent use at full capacity. As with a kettle or washing machine
etc. Hence things like 13 amp water heaters normally not plugged in, but
hard wired. Same sort of thing with storage rads.

Even more so if cooling to the socket/plug is restricted in any way.

The answer is to go for an industrial 16 amp plug and socket - if indeed
it has to have a plug/socket arrangement.

--
*Thank you. We're all refreshed and challenged by your unique point of view

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

On 15/05/2018 06:24, Archibald Tarquin Blenkinsopp wrote:
On Tue, 15 May 2018 03:14:02 GMT, Lea Goldberg
m wrote:

.so,for the first 2 years,my comet kiln worked perfectly...then the socket
burnt out,replaced it(always ised a professional electrician)thos time,socket
switches got hardrr and harder to switch on,then the socket stopped working
again,replaced the whole unit...now its happened again...the socket is about
20 ft via armoured cable to the house,the kiln room isnt damp...the kilns
fine,but the plug gets a bit hot(when it worked)the electrician seems to be
baffled...'must be your kiln'...but i know nothing about electrics so cant
argue the toss!can ANYONE help...its driving me mad....

Well if it baffled your professional electrician, there's your
problem.

What subnormal idiot thought that a damp kiln room could have any
bearing on socket condition/ temperature 20 feet away?


I read it as the socket/plug is next to the kiln where the socket is at
the (shed?) end of the 20ft of armoured cable.


--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk

On 15/05/2018 11:17, Dave Plowman (News) wrote:
In article ,
Lea Goldberg m wrote:
.so,for the first 2 years,my comet kiln worked perfectly...then the
socket burnt out,replaced it(always ised a professional electrician)thos
time,socket switches got hardrr and harder to switch on,then the socket
stopped working again,replaced the whole unit...now its happened
again...the socket is about 20 ft via armoured cable to the house,the
kiln room isnt damp...the kilns fine,but the plug gets a bit hot(when it
worked)the electrician seems to be baffled...'must be your kiln'...but i
know nothing about electrics so cant argue the toss!can ANYONE
help...its driving me mad....

Despite being rated at 13 amps, most sockets and plugs aren't happy to
carry that for very long periods. They are a domestic connector and really
for intermittent use at full capacity. As with a kettle or washing machine
etc. Hence things like 13 amp water heaters normally not plugged in, but
hard wired. Same sort of thing with storage rads.

Even more so if cooling to the socket/plug is restricted in any way.

The answer is to go for an industrial 16 amp plug and socket - if indeed
it has to have a plug/socket arrangement.

There is also a 32 amp, which is perhaps better if it is protected by a
32A MCB, as an earlier poster pointed out. Of course you should be using
30 Amp cable too. (Sorry about the URL)

https://www.tlc-direct.co.uk/Product...yABEgL4z_D_BwE

---
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On Tuesday, 15 May 2018 04:14:04 UTC+1, Lea Goldberg wrote:
.so,for the first 2 years,my comet kiln worked perfectly...then the socket
burnt out,replaced it(always ised a professional electrician)thos time,socket
switches got hardrr and harder to switch on,then the socket stopped working
again,replaced the whole unit...now its happened again...the socket is about
20 ft via armoured cable to the house,the kiln room isnt damp...the kilns
fine,but the plug gets a bit hot(when it worked)the electrician seems to be
baffled...'must be your kiln'...but i know nothing about electrics so cant
argue the toss!can ANYONE help...its driving me mad....

possibilities:
the kiln draws more than 13A, maybe due to some turns of the heating wire being crossed.
plug or socket not of best quality
fuse not completely clean or not best quality

Also as said, plugs & sockets don't do well running at 13A for long times. Try an FCU.


NT

On 15/05/2018 11:17, Dave Plowman (News) wrote:
In article ,
Lea Goldberg m wrote:
.so,for the first 2 years,my comet kiln worked perfectly...then the
socket burnt out,replaced it(always ised a professional electrician)thos
time,socket switches got hardrr and harder to switch on,then the socket
stopped working again,replaced the whole unit...now its happened
again...the socket is about 20 ft via armoured cable to the house,the
kiln room isnt damp...the kilns fine,but the plug gets a bit hot(when it
worked)the electrician seems to be baffled...'must be your kiln'...but i
know nothing about electrics so cant argue the toss!can ANYONE
help...its driving me mad....

Despite being rated at 13 amps, most sockets and plugs aren't happy to
carry that for very long periods. They are a domestic connector and really
for intermittent use at full capacity. As with a kettle or washing machine
etc. Hence things like 13 amp water heaters normally not plugged in, but
hard wired. Same sort of thing with storage rads.

Indeed. 3kW is pushing it on a standard plug and socket for a near
continuous load. They are fine for intermittent loads like kettles.

ISTR there is a revision that recommends no portable appliances with
load 2.4kW due to the fragile nature of nominally 13A plug and sockets.

Even more so if cooling to the socket/plug is restricted in any way.

The answer is to go for an industrial 16 amp plug and socket - if indeed
it has to have a plug/socket arrangement.

+1

Or hardwired fused spur like a hot water cylinder immersion heater.

--
Regards,
Martin Brown

On Tue, 15 May 2018 11:40:25 +0100, newshound
wrote:

There is also a 32 amp, which is perhaps better if it is protected by a
32A MCB, as an earlier poster pointed out. Of course you should be using
30 Amp cable too. (Sorry about the URL)

https://www.tlc-direct.co.uk/Product...yABEgL4z_D_BwE


That could prove a bit of a shock hazard as it's the wrong gender.

Try

https://www.tlc-direct.co.uk/Products/MKK9233BLU.html

--

On 15/05/2018 11:58, Martin Brown wrote:
On 15/05/2018 11:17, Dave Plowman (News) wrote:

snipped

Despite being rated at 13 amps, most sockets and plugs aren't happy to
carry that for very long periods. They are a domestic connector and
really
for intermittent use at full capacity. As with a kettle or washing
machine
etc. Hence things like 13 amp water heaters normally not plugged in, but
hard wired. Same sort of thing with storage rads.

Indeed. 3kW is pushing it on a standard plug and socket for a near
continuous load. They are fine for intermittent loads like kettles.

ISTR there is a revision that recommends no portable appliances with
load 2.4kW due to the fragile nature of nominally 13A plug and sockets.

I can't see anything official (and I didn't try that hard) but a
supporting data point is fan heaters. Usually 2kW max, sometimes a
little more, but I've not seen 3kW.

Cheers
--
Clive

On 15/05/2018 13:01, Clive Arthur wrote:
On 15/05/2018 11:58, Martin Brown wrote:
On 15/05/2018 11:17, Dave Plowman (News) wrote:

snipped

Despite being rated at 13 amps, most sockets and plugs aren't happy to
carry that for very long periods. They are a domestic connector and
really
for intermittent use at full capacity. As with a kettle or washing
machine
etc. Hence things like 13 amp water heaters normally not plugged in, but
hard wired. Same sort of thing with storage rads.

Indeed. 3kW is pushing it on a standard plug and socket for a near
continuous load. They are fine for intermittent loads like kettles.

ISTR there is a revision that recommends no portable appliances with
load 2.4kW due to the fragile nature of nominally 13A plug and sockets.

I can't see anything official (and I didn't try that hard) but a
supporting data point is fan heaters.Â* Usually 2kW max, sometimes a
little more, but I've not seen 3kW.

I don't know where it is in what legislation but it came up in
conversation with a sparks doing some alterations at out VH.

I have a 3kW fan heater and it has cooked a plug and socket not quite to
the point of failure but more than I was comfortable with one cold day.
Enough to significantly discolour and distort the plastic casings.

--
Regards,
Martin Brown

On Tue, 15 May 2018 11:31:11 +0100, alan_m
wrote:

On 15/05/2018 06:24, Archibald Tarquin Blenkinsopp wrote:
On Tue, 15 May 2018 03:14:02 GMT, Lea Goldberg
m wrote:

.so,for the first 2 years,my comet kiln worked perfectly...then the socket
burnt out,replaced it(always ised a professional electrician)thos time,socket
switches got hardrr and harder to switch on,then the socket stopped working
again,replaced the whole unit...now its happened again...the socket is about
20 ft via armoured cable to the house,the kiln room isnt damp...the kilns
fine,but the plug gets a bit hot(when it worked)the electrician seems to be
baffled...'must be your kiln'...but i know nothing about electrics so cant
argue the toss!can ANYONE help...its driving me mad....

Well if it baffled your professional electrician, there's your
problem.

What subnormal idiot thought that a damp kiln room could have any
bearing on socket condition/ temperature 20 feet away?


I read it as the socket/plug is next to the kiln where the socket is at
the (shed?) end of the 20ft of armoured cable.

Correct, I misunderstood when reading the original.

The problem should be pretty damned obvious though to anyone with a
basic idea of electrical work.

Socket burnt out means nothing until inspection, it may simply be a
loose cable.

It could be a cheap nasty socket with a sliver of bent brass carrying
the 13A. BS marks seem to get onto anything with square pins these
days.

Current information summary, socket burnt, replaced by "professional"

Went again, Ditto

Went again, overheating, Electrician baffled

1. Inspection of the defective items should be more than enough to
indicate the reasons for the problem.

2, Instead of being "baffled" if the "electrician" measured the
current drawn, then it would remove one item of uncertainty.


Personally I would suggest that the major problem is the choice of
electrician.

AB

On Tue, 15 May 2018 03:50:51 -0700 (PDT), wrote:

On Tuesday, 15 May 2018 04:14:04 UTC+1, Lea Goldberg wrote:
.so,for the first 2 years,my comet kiln worked perfectly...then the socket
burnt out,replaced it(always ised a professional electrician)thos time,socket
switches got hardrr and harder to switch on,then the socket stopped working
again,replaced the whole unit...now its happened again...the socket is about
20 ft via armoured cable to the house,the kiln room isnt damp...the kilns
fine,but the plug gets a bit hot(when it worked)the electrician seems to be
baffled...'must be your kiln'...but i know nothing about electrics so cant
argue the toss!can ANYONE help...its driving me mad....

possibilities:
the kiln draws more than 13A, maybe due to some turns of the heating wire being crossed.
plug or socket not of best quality
fuse not completely clean or not best quality

Also as said, plugs & sockets don't do well running at 13A for long times. Try an FCU.


NT


Only if you buy Cheap.

The type of socket wasn't stated.



BS1363-2:1995 requires for double socket outlets that both socket
outlets have loads applied via test plugs, 1 test plug having a load
of 14 amps whilst the other has a load of 6 amps, making a total load
of 20 amps on the cable supplying the double socket outlet. The double
socket outlet is then subjected to this loading for a minimum
continuous period of 4 hours or longer until stability is reached with
a maximum duration of 8 hours (stability being taken as less than 1
degC rise within 1 h). The test is passed if neither the terminals /
terminations, nor the accessible external surface, increase in
temperature by more than 52 degC.


AB

In article ,
Clive Arthur wrote:
I can't see anything official (and I didn't try that hard) but a
supporting data point is fan heaters. Usually 2kW max, sometimes a
little more, but I've not seen 3kW.

I've got a 3Kw one here as a standby. Is pretty old, though. Made of steel
rather than plastic.

--
*I don't suffer from insanity; I enjoy every minute of it.

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

In article ,
Archibald Tarquin Blenkinsopp wrote:
Socket burnt out means nothing until inspection, it may simply be a
loose cable.

It could be a cheap nasty socket with a sliver of bent brass carrying
the 13A. BS marks seem to get onto anything with square pins these
days.

Those original MK surface mount 13 amp sockets (and the matching plug)
used to cook too. As anyone who's removed them when re-wiring will have
found. Usually plenty scorch marks.

--
*A picture may be worth a thousand words, but it uses up a thousand times more memory.

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

In article ,
Archibald Tarquin Blenkinsopp wrote:
Only if you buy Cheap.

The type of socket wasn't stated.



BS1363-2:1995 requires for double socket outlets that both socket
outlets have loads applied via test plugs, 1 test plug having a load
of 14 amps whilst the other has a load of 6 amps, making a total load
of 20 amps on the cable supplying the double socket outlet. The double
socket outlet is then subjected to this loading for a minimum
continuous period of 4 hours or longer until stability is reached with
a maximum duration of 8 hours (stability being taken as less than 1
degC rise within 1 h). The test is passed if neither the terminals /
terminations, nor the accessible external surface, increase in
temperature by more than 52 degC.

A double socket with two plugs taking a total 20 amps might well run
cooler than a single at 13 amps. More 'air' around it.

--
*There are 3 kinds of people: those who can count & those who can't.

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

On Tuesday, 15 May 2018 13:01:12 UTC+1, Clive Arthur wrote:
On 15/05/2018 11:58, Martin Brown wrote:
On 15/05/2018 11:17, Dave Plowman (News) wrote:

snipped

Despite being rated at 13 amps, most sockets and plugs aren't happy to
carry that for very long periods. They are a domestic connector and
really
for intermittent use at full capacity. As with a kettle or washing
machine
etc. Hence things like 13 amp water heaters normally not plugged in, but
hard wired. Same sort of thing with storage rads.

Indeed. 3kW is pushing it on a standard plug and socket for a near
continuous load. They are fine for intermittent loads like kettles.

ISTR there is a revision that recommends no portable appliances with
load 2.4kW due to the fragile nature of nominally 13A plug and sockets.

I can't see anything official (and I didn't try that hard) but a
supporting data point is fan heaters. Usually 2kW max, sometimes a
little more, but I've not seen 3kW.

Cheers

You've not done much looking then.

On Tuesday, 15 May 2018 13:33:10 UTC+1, Archibald Tarquin Blenkinsopp wrote:
On Tue, 15 May 2018 03:50:51 -0700 (PDT), tabbypurr wrote:
On Tuesday, 15 May 2018 04:14:04 UTC+1, Lea Goldberg wrote:

.so,for the first 2 years,my comet kiln worked perfectly...then the socket
burnt out,replaced it(always ised a professional electrician)thos time,socket
switches got hardrr and harder to switch on,then the socket stopped working
again,replaced the whole unit...now its happened again...the socket is about
20 ft via armoured cable to the house,the kiln room isnt damp...the kilns
fine,but the plug gets a bit hot(when it worked)the electrician seems to be
baffled...'must be your kiln'...but i know nothing about electrics so cant
argue the toss!can ANYONE help...its driving me mad....

possibilities:
the kiln draws more than 13A, maybe due to some turns of the heating wire being crossed.
plug or socket not of best quality
fuse not completely clean or not best quality

Also as said, plugs & sockets don't do well running at 13A for long times. Try an FCU.


NT


Only if you buy Cheap.

The type of socket wasn't stated.



BS1363-2:1995 requires for double socket outlets that both socket
outlets have loads applied via test plugs, 1 test plug having a load
of 14 amps whilst the other has a load of 6 amps, making a total load
of 20 amps on the cable supplying the double socket outlet. The double
socket outlet is then subjected to this loading for a minimum
continuous period of 4 hours or longer until stability is reached with
a maximum duration of 8 hours (stability being taken as less than 1
degC rise within 1 h). The test is passed if neither the terminals /
terminations, nor the accessible external surface, increase in
temperature by more than 52 degC.


AB

you're missing the point. They deteriorate over time.


NT

On 15/05/2018 13:33, Archibald Tarquin Blenkinsopp wrote:

The test is passed if neither the terminals /
terminations, nor the accessible external surface, increase in
temperature by more than 52 degC.

This will be a one off laboratory test and not necessarily
representative of the equivalent same test (operation of a kiln)
repeated over regular period over years.

It's much like the mpg figures that car manufactures publish but then in
small print tell you that they are not real world figures. And, just
look how clean diesel cars are!

An increase of 52C from an ambient of, say, 20C takes the temperature to
72C. I would expect prolonged use at 72C to degrade the performance in a
relatively short time. There may also be a problem of screw terminals
and thermal cycling where the temperature regularly changes by 50C.


--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk

On 15/05/2018 13:50, Dave Plowman (News) wrote:
In article ,
Archibald Tarquin Blenkinsopp wrote:
Socket burnt out means nothing until inspection, it may simply be a
loose cable.

It could be a cheap nasty socket with a sliver of bent brass carrying
the 13A. BS marks seem to get onto anything with square pins these
days.

Those original MK surface mount 13 amp sockets (and the matching plug)
used to cook too. As anyone who's removed them when re-wiring will have
found. Usually plenty scorch marks.


Anyone who has done some DIY electrical work and purchased no-name
plugs/sockets from the sheds probably knows that they can be vastly
inferior to MK branded products. If MK can burn what hope is there for
an inferior product?



--
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On Tue, 15 May 2018 13:53:30 +0100, "Dave Plowman (News)"
wrote:

In article ,
Archibald Tarquin Blenkinsopp wrote:
Only if you buy Cheap.

The type of socket wasn't stated.



BS1363-2:1995 requires for double socket outlets that both socket
outlets have loads applied via test plugs, 1 test plug having a load
of 14 amps whilst the other has a load of 6 amps, making a total load
of 20 amps on the cable supplying the double socket outlet. The double
socket outlet is then subjected to this loading for a minimum
continuous period of 4 hours or longer until stability is reached with
a maximum duration of 8 hours (stability being taken as less than 1
degC rise within 1 h). The test is passed if neither the terminals /
terminations, nor the accessible external surface, increase in
temperature by more than 52 degC.

A double socket with two plugs taking a total 20 amps might well run
cooler than a single at 13 amps. More 'air' around it.

On the face of it yes.

The areas of the socket dissipating power will not be the conductors,
they will be the interface or the relatively high resistance between
the male and female prongs.

Two plugs will dissipate more than a single unit of twice the current
[generally speaking].


AB

On Tue, 15 May 2018 14:42:38 +0100, alan_m
wrote:

On 15/05/2018 13:33, Archibald Tarquin Blenkinsopp wrote:

The test is passed if neither the terminals /
terminations, nor the accessible external surface, increase in
temperature by more than 52 degC.

This will be a one off laboratory test and not necessarily
representative of the equivalent same test (operation of a kiln)
repeated over regular period over years.

It's much like the mpg figures that car manufactures publish but then in
small print tell you that they are not real world figures. And, just
look how clean diesel cars are!

An increase of 52C from an ambient of, say, 20C takes the temperature to
72C. I would expect prolonged use at 72C to degrade the performance in a
relatively short time. There may also be a problem of screw terminals
and thermal cycling where the temperature regularly changes by 50C.

Not really a problem to diagnose, yellowing of the surrounding area
should be enough to take any "competent" electrician out of his
bafflement.

My point is, that whatever the hardware in use, if the post is an
accurate record, then the electrician was unfit for purpose.

3kW kilns are sold on the basis that they can be supplied via a 13A
plug, they are not 3kW on a permanent basis, they are reasonably well
insulated anyway.

If the thing was over 3kW even a domestic electrician should be
capable of verifying the fact.


AB

On Tue, 15 May 2018 06:28:17 -0700 (PDT), wrote:

On Tuesday, 15 May 2018 13:01:12 UTC+1, Clive Arthur wrote:
On 15/05/2018 11:58, Martin Brown wrote:
On 15/05/2018 11:17, Dave Plowman (News) wrote:

snipped

Despite being rated at 13 amps, most sockets and plugs aren't happy to
carry that for very long periods. They are a domestic connector and
really
for intermittent use at full capacity. As with a kettle or washing
machine
etc. Hence things like 13 amp water heaters normally not plugged in, but
hard wired. Same sort of thing with storage rads.

Indeed. 3kW is pushing it on a standard plug and socket for a near
continuous load. They are fine for intermittent loads like kettles.

ISTR there is a revision that recommends no portable appliances with
load 2.4kW due to the fragile nature of nominally 13A plug and sockets.

I can't see anything official (and I didn't try that hard) but a
supporting data point is fan heaters. Usually 2kW max, sometimes a
little more, but I've not seen 3kW.

Cheers

You've not done much looking then.

They can be found, I have a few. 2kW isn't enough for an average room
in winter.

3kW are around but can be expensive, the cheaper end of the range are
festooned with noisy and sticking fans.


I tend to wonder if the reason that there are not so many is because
of the thermal overload/ plastic shell combination.

I have overloads trip farlt often, in obstacle free surroundings. They
have a limited trip life too. After half a dozen trip events, the
springiness of the trip seems to go, preventing the fan heater working
permanently.


I dropped a 250 degree thermal fuse across one, this blew also.

I might have to do some checks to see if a higher rating is practical.

AB

Dave Plowman wrote:

A double socket with two plugs taking a total 20 amps might well run
cooler than a single at 13 amps. More 'air' around it.

but the test isn't 2x10A, it's 14A+6A

On Tue, 15 May 2018 13:13:15 +0100, Martin Brown
wrote:

On 15/05/2018 13:01, Clive Arthur wrote:
On 15/05/2018 11:58, Martin Brown wrote:
On 15/05/2018 11:17, Dave Plowman (News) wrote:

snipped

Despite being rated at 13 amps, most sockets and plugs aren't happy to
carry that for very long periods. They are a domestic connector and
really
for intermittent use at full capacity. As with a kettle or washing
machine
etc. Hence things like 13 amp water heaters normally not plugged in, but
hard wired. Same sort of thing with storage rads.

Indeed. 3kW is pushing it on a standard plug and socket for a near
continuous load. They are fine for intermittent loads like kettles.

ISTR there is a revision that recommends no portable appliances with
load 2.4kW due to the fragile nature of nominally 13A plug and sockets.

I can't see anything official (and I didn't try that hard) but a
supporting data point is fan heaters.* Usually 2kW max, sometimes a
little more, but I've not seen 3kW.

I don't know where it is in what legislation but it came up in
conversation with a sparks doing some alterations at out VH.

I have a 3kW fan heater and it has cooked a plug and socket not quite to
the point of failure but more than I was comfortable with one cold day.
Enough to significantly discolour and distort the plastic casings.

You know that "cheapest first" option you get in the listings on
Ebay.................................. :-)



I play at PAT testing from time to time, I always strip and examine
the failiures, a lot of the cheaper multiway sockets fail due to
discolouration. The conductors are not exactly very generous on size
or contact area.

For a 3kW heater, I would go MK or a similar known brand.

AB

"Archibald Tarquin Blenkinsopp" wrote in
message ...
For a 3kW heater, I would go MK or a similar known brand.

And ideally hard-wire it, as for a cooker. I've noticed 3-bar electric fire
plugs get quite warm, even on 2 bars (2 kW). Given the high current that
fires draw, I got into the habit of checking the plug every so often. On one
occasion I found that the neutral wire was down to just a few strands and
the insulation had melted so evidently that bit of narrower wire had got
rather hot. Of course if you cut that bit of wire off and start afresh, you
also have to do the other two wires to shorten them correspondingly.

When my oven stopped working, I removed it (the oven was separate from the
gas hob above it) and was surprised to see that the "Cooker" switch on the
wall simply switched a pair of 3-pin sockets. The oven was plugged into one
and the lighting mechanism for the gas hob went into the other. I'd expected
the oven to be hard-wired and that I'd have to do battle with ring-main
grade cable. As it is, it was just the 13A fuse that had blown so it was a
quick repair - the longest thing was working out how to unscrew and slide
the oven out of the worktop/cupboards into which it had been fitted by the
builders.

On Tue, 15 May 2018 15:48:59 +0100, "NY" wrote:

"Archibald Tarquin Blenkinsopp" wrote in
message ...
For a 3kW heater, I would go MK or a similar known brand.

And ideally hard-wire it, as for a cooker. I've noticed 3-bar electric fire
plugs get quite warm, even on 2 bars (2 kW). Given the high current that
fires draw, I got into the habit of checking the plug every so often. On one
occasion I found that the neutral wire was down to just a few strands and
the insulation had melted so evidently that bit of narrower wire had got
rather hot. Of course if you cut that bit of wire off and start afresh, you
also have to do the other two wires to shorten them correspondingly.

When my oven stopped working, I removed it (the oven was separate from the
gas hob above it) and was surprised to see that the "Cooker" switch on the
wall simply switched a pair of 3-pin sockets. The oven was plugged into one
and the lighting mechanism for the gas hob went into the other. I'd expected
the oven to be hard-wired and that I'd have to do battle with ring-main
grade cable. As it is, it was just the 13A fuse that had blown so it was a
quick repair - the longest thing was working out how to unscrew and slide
the oven out of the worktop/cupboards into which it had been fitted by the
builders.

From my experience, with good quality kit terminated correctly, 13A
isn't a problem on a domestic socket.

Any loose connection, or even crud on the pins of a plug will raise
the resistance to the point where damage to conductors occur's

Indeed some plugs seem to do well where the point of contact to the
fuse is merely at three spots stamped out of a sheet of copper or
brass.

One dodgy connection and overheating can and does occur. The plus
point is that it does not take a degree in thermodtnamics to pinpoint
the source.

AB

In article ,
Andy Burns wrote:
A double socket with two plugs taking a total 20 amps might well run
cooler than a single at 13 amps. More 'air' around it.

but the test isn't 2x10A, it's 14A+6A

I didn't say it was.

Heating of a connector happens because of resistance. The same resistance
will result in more heat with more current. Likely balancing things out in
a twin type with the same total current.

--
*I get enough exercise just pushing my luck.

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

On 15/05/2018 12:54, The Other Mike wrote:
On Tue, 15 May 2018 11:40:25 +0100, newshound
wrote:

There is also a 32 amp, which is perhaps better if it is protected by a
32A MCB, as an earlier poster pointed out. Of course you should be using
30 Amp cable too. (Sorry about the URL)

https://www.tlc-direct.co.uk/Product...yABEgL4z_D_BwE


That could prove a bit of a shock hazard as it's the wrong gender.

Try

https://www.tlc-direct.co.uk/Products/MKK9233BLU.html

Oops!

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In article ,
says...


Heating of a connector happens because of resistance. The same resistance
will result in more heat with more current.

The contact spring tension has to be a compremise between
insertion force versus contact force so why can't someone
devise a switched 13A socket which uses a cam arrangement to
increase the contact force, reducing resistance, when the
switch is moved to the on position?

(Personally, I prefer unswitched sockets but even when you
find them these days, they are more expensive than the
switched version!)


--

Terry

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On 15/05/2018 08:29, newshound wrote:
On 15/05/2018 07:57, Tricky Dicky wrote:
There appears to be two versions of the Comet Kiln, the ECO which
draws 3kW which should be fine using a 13A plug in a standard
socket. The other is a 5.5kW model for which a plug and socket is
totally inadequate. There should be a ratings plate somewhere on
the kiln check the wattage, although I would have thought your
professional electrician would have checked that first.

Richard

Good point.

The other thing I would suggest even for the 3 kW model is to get
your sparks to fit a "cooker" type breaker switch and then an
industrial type plug and socket like this:

https://uk.rs-online.com/web/p/produ...E&gclsrc=aw.ds
I would suggest that if you are fitting a socket like that a 32A one
might be better as they cost about the same.