Electrical code Compliance - How good is ETL safety certification?

Author

How good is ETL safety certification?

larry moe 'n curly

2005-12-14, 10:21 am

I see appliances being sold now that lack UL or CSA approval markings
and instead are only ETL certified.

How good is ETL certification compared to those from UL and CSA?

Does ETL require actual sample products to be submitted for testing, or
are they like CE and let manufacturers work on the honor system (I have
a CE approved multimeter rated for use at up to 500V, but its fuses are
rated for only 250V, unlike a UL-approved Fluke).

Are coffee makers required to be made of fire resistant plastic by any
of the safety certification organizations? If so, which ones?

I'm asking all this because I noticed that an ETL-approved drip coffee
maker had only a bimetal thermostat to turn off the current while an
older UL-approved coffee maker also had two thermal fuses in series..

Dan Hollands

2005-12-14, 1:21 pm

In the late 80's law was passed to allow other than specification writing
agencies to do testing to specifications such as UL

See http://www.labconco.com/company/sta...certs/etl.shtml for more
details.

Of course one really has to know what specifications the product is being
certified to.

There are a multitude of UL and IEC specifications that cover different
products and product applications.

Dan

--
Dan Hollands
1120 S Creek Dr
Webster NY 14580
585-872-2606
dhollan3@rochester.rr.com
www.QuickScoreRace.com
"larry moe 'n curly" <larrymoencurly@my-deja.com> wrote in message
news:1134568031.597554.72250@z14g2000cwz.googlegroups.com...
>I see appliances being sold now that lack UL or CSA approval markings
> and instead are only ETL certified.
>
> How good is ETL certification compared to those from UL and CSA?
>
> Does ETL require actual sample products to be submitted for testing, or
> are they like CE and let manufacturers work on the honor system (I have
> a CE approved multimeter rated for use at up to 500V, but its fuses are
> rated for only 250V, unlike a UL-approved Fluke).
>
> Are coffee makers required to be made of fire resistant plastic by any
> of the safety certification organizations? If so, which ones?
>
> I'm asking all this because I noticed that an ETL-approved drip coffee
> maker had only a bimetal thermostat to turn off the current while an
> older UL-approved coffee maker also had two thermal fuses in series..
>

Leo Yaus

2005-12-14, 2:21 pm

ETL certification is valid. Whether to use UL or CSA or ETL is a matter of
cost, schedule, customer service, and factory location (proximity of facotry
to service provider affects FUS [follow-up service] costs).
ETL would require samples and documentation.
CE is just a mark, not an organization. ETL (like UL and many others) can
provide services permitting usage of the CE mark.
Your meter rated at 500V but having 250V fuses is not odd. These fuses are
for overcurrent protection, and 250V is the highest nominal value for
commonly available replacement fuses.
Coffee makers require flame retardant plastic (94-V0 or V1). Standard is
EN60335?
Thermostat versus two thermal fuses is an individual manufacturer's design
consideration. Either of these or other protection methods are valid as
long as all of these test in the standard(s) can be met.

"larry moe 'n curly" <larrymoencurly@my-deja.com> wrote in message
news:1134568031.597554.72250@z14g2000cwz.googlegroups.com...
>I see appliances being sold now that lack UL or CSA approval markings
> and instead are only ETL certified.
>
> How good is ETL certification compared to those from UL and CSA?
>
> Does ETL require actual sample products to be submitted for testing, or
> are they like CE and let manufacturers work on the honor system (I have
> a CE approved multimeter rated for use at up to 500V, but its fuses are
> rated for only 250V, unlike a UL-approved Fluke).
>
> Are coffee makers required to be made of fire resistant plastic by any
> of the safety certification organizations? If so, which ones?
>
> I'm asking all this because I noticed that an ETL-approved drip coffee
> maker had only a bimetal thermostat to turn off the current while an
> older UL-approved coffee maker also had two thermal fuses in series..
>

larry moe 'n curly

2005-12-14, 6:21 pm

Leo Yaus wrote:

> Your meter rated at 500V but having 250V fuses is not odd. These fuses are
> for overcurrent protection, and 250V is the highest nominal value for
> commonly available replacement fuses.

Is there a chance that a fuse with a too low a voltage rating can
explode violently enough to pierce through the case? I noticed that
the 600V fuse in a Fluke meter was enclosed in woven fabric, possibly
for such a rupture.

> Coffee makers require flame retardant plastic (94-V0 or V1). Standard is
> EN60335?
> Thermostat versus two thermal fuses is an individual manufacturer's design
> consideration. Either of these or other protection methods are valid as
> long as all of these test in the standard(s) can be met.

I thought a coffee maker would be required to have a backup means of
shutting off the current in case the bimetal thermostat failed because
back in the 1970s or 1980s there was a big lawsuit against GE when
thermostats in some of its coffee makers failed and caused fires.

SQLit

2005-12-14, 7:21 pm

"larry moe 'n curly" <larrymoencurly@my-deja.com> wrote in message
news:1134596475.002546.160650@z14g2000cwz.googlegroups.com...
>
> Leo Yaus wrote:
>
are[color=darkred]
>
> Is there a chance that a fuse with a too low a voltage rating can
> explode violently enough to pierce through the case? I noticed that
> the 600V fuse in a Fluke meter was enclosed in woven fabric, possibly
> for such a rupture.
>
is[color=darkred]
design[color=darkred]
>
> I thought a coffee maker would be required to have a backup means of
> shutting off the current in case the bimetal thermostat failed because
> back in the 1970s or 1980s there was a big lawsuit against GE when
> thermostats in some of its coffee makers failed and caused fires.

Back up>>>> your joking. I have had it with most of the coffee makers on
the market. I plug them in in the morning and unplug them when done. Tired
of the crappy el-cheapo stuff. If it aint plugged in it certainly will not
hurt anything.

SQLit

2005-12-14, 10:21 pm

Spindler of Kittens

2005-12-15, 12:21 pm

"larry moe 'n curly" <larrymoencurly@my-deja.com> wrote in message
news:1134596475.002546.160650@z14g2000cwz.googlegroups.com...
:
: Leo Yaus wrote:
:
: > Your meter rated at 500V but having 250V fuses is not odd. These
fuses are
: > for overcurrent protection, and 250V is the highest nominal value
for
: > commonly available replacement fuses.
:
: Is there a chance that a fuse with a too low a voltage rating can
: explode violently enough to pierce through the case? I noticed that
: the 600V fuse in a Fluke meter was enclosed in woven fabric,
possibly
: for such a rupture.
:
: > Coffee makers require flame retardant plastic (94-V0 or V1).
Standard is
: > EN60335?
: > Thermostat versus two thermal fuses is an individual
manufacturer's design
: > consideration. Either of these or other protection methods are
valid as
: > long as all of these test in the standard(s) can be met.
:
: I thought a coffee maker would be required to have a backup means of
: shutting off the current in case the bimetal thermostat failed
because
: back in the 1970s or 1980s there was a big lawsuit against GE when
: thermostats in some of its coffee makers failed and caused fires.

I've had the delightful experience (~1980) of being in a computer lab
next to an office where someone left one of those things going, when
they left for the day. An unforgettable experience...by the time we
could smell the smoke in the lab, the office was completely engulfed
in flames.

Are they really any safer, now? Seeing the efforts big business has
been making to remove government oversight where it can, I'm not
terribly confident about that.

TKM

2005-12-15, 9:21 pm

"Spindler of Kittens" <misleart@ameritech.net> wrote in message
news:5cgof.38489$Zv5.25477@newssvr25.news.prodigy.net...
> "larry moe 'n curly" <larrymoencurly@my-deja.com> wrote in message
> news:1134596475.002546.160650@z14g2000cwz.googlegroups.com...
> :
> : Leo Yaus wrote:
> :
> : > Your meter rated at 500V but having 250V fuses is not odd. These
> fuses are
> : > for overcurrent protection, and 250V is the highest nominal value
> for
> : > commonly available replacement fuses.
> :
> : Is there a chance that a fuse with a too low a voltage rating can
> : explode violently enough to pierce through the case? I noticed that
> : the 600V fuse in a Fluke meter was enclosed in woven fabric,
> possibly
> : for such a rupture.
> :
> : > Coffee makers require flame retardant plastic (94-V0 or V1).
> Standard is
> : > EN60335?
> : > Thermostat versus two thermal fuses is an individual
> manufacturer's design
> : > consideration. Either of these or other protection methods are
> valid as
> : > long as all of these test in the standard(s) can be met.
> :
> : I thought a coffee maker would be required to have a backup means of
> : shutting off the current in case the bimetal thermostat failed
> because
> : back in the 1970s or 1980s there was a big lawsuit against GE when
> : thermostats in some of its coffee makers failed and caused fires.
>
> I've had the delightful experience (~1980) of being in a computer lab
> next to an office where someone left one of those things going, when
> they left for the day. An unforgettable experience...by the time we
> could smell the smoke in the lab, the office was completely engulfed
> in flames.
>
> Are they really any safer, now? Seeing the efforts big business has
> been making to remove government oversight where it can, I'm not
> terribly confident about that.

UL isn't government. From my experience (mostly residential lighting
equipment), I haven't noticed any relaxation of standards for fire or
electrical safety. If anytthing, It has been just the opposite.
Competition appears to be good for UL. Manufacturers have options including
ETL and CSA (Canadian Standards Association) and others so there are
alternatives. That helps costs and speed of testing. They all test to the
same standards. Some lighting equipment standards are now tri-national (US,
Canada and Mexico).

TKM

Spindler of Kittens

2005-12-16, 5:21 pm

"TKM" <nomail@no.net> wrote in message
news:w_nof.159404$qk4.109524@bgtnsc05-news.ops.worldnet.att.net...
:
: "Spindler of Kittens" <misleart@ameritech.net> wrote in message
: news:5cgof.38489$Zv5.25477@newssvr25.news.prodigy.net...
: > "larry moe 'n curly" <larrymoencurly@my-deja.com> wrote in message
: > news:1134596475.002546.160650@z14g2000cwz.googlegroups.com...
: > :
: > : Leo Yaus wrote:
: > :
: > : > Your meter rated at 500V but having 250V fuses is not odd.
These
: > fuses are
: > : > for overcurrent protection, and 250V is the highest nominal
value
: > for
: > : > commonly available replacement fuses.
: > :
: > : Is there a chance that a fuse with a too low a voltage rating
can
: > : explode violently enough to pierce through the case? I noticed
that
: > : the 600V fuse in a Fluke meter was enclosed in woven fabric,
: > possibly
: > : for such a rupture.
: > :
: > : > Coffee makers require flame retardant plastic (94-V0 or V1).
: > Standard is
: > : > EN60335?
: > : > Thermostat versus two thermal fuses is an individual
: > manufacturer's design
: > : > consideration. Either of these or other protection methods
are
: > valid as
: > : > long as all of these test in the standard(s) can be met.
: > :
: > : I thought a coffee maker would be required to have a backup
means of
: > : shutting off the current in case the bimetal thermostat failed
: > because
: > : back in the 1970s or 1980s there was a big lawsuit against GE
when
: > : thermostats in some of its coffee makers failed and caused
fires.
: >
: > I've had the delightful experience (~1980) of being in a computer
lab
: > next to an office where someone left one of those things going,
when
: > they left for the day. An unforgettable experience...by the time
we
: > could smell the smoke in the lab, the office was completely
engulfed
: > in flames.
: >
: > Are they really any safer, now? Seeing the efforts big business
has
: > been making to remove government oversight where it can, I'm not
: > terribly confident about that.
:
: UL isn't government.

Never said they were. UL doesn't make the laws, you know? What I'm
saying, is that big business always has, and always will try to make
an endrun around the rules, if it seems profitable, especially if it
looks like no one will ever catch them.

: From my experience (mostly residential lighting
: equipment), I haven't noticed any relaxation of standards for fire
or
: electrical safety. If anytthing, It has been just the opposite.
: Competition appears to be good for UL. Manufacturers have options
including
: ETL and CSA (Canadian Standards Association) and others so there are
: alternatives. That helps costs and speed of testing. They all test
to the
: same standards. Some lighting equipment standards are now
tri-national (US,
: Canada and Mexico).

Even if UL or some other agency has tested the products, there is
still room for poor QA...and some people cheat, when it comes to
keeping to the standards, too. Just because something you're familiar
with doesn't appear to have any problems, doesn't mean there aren't
any, either.

TKM

2005-12-21, 11:21 am

"Spindler of Kittens" <misleart@ameritech.net> wrote in message
news:HDFof.42587$Zv5.28093@newssvr25.news.prodigy.net...
> "TKM" <nomail@no.net> wrote in message
> news:w_nof.159404$qk4.109524@bgtnsc05-news.ops.worldnet.att.net...
> :
> : "Spindler of Kittens" <misleart@ameritech.net> wrote in message
> : news:5cgof.38489$Zv5.25477@newssvr25.news.prodigy.net...
> : > "larry moe 'n curly" <larrymoencurly@my-deja.com> wrote in message
> : > news:1134596475.002546.160650@z14g2000cwz.googlegroups.com...
> : > :
> : > : Leo Yaus wrote:
> : > :
> : > : > Your meter rated at 500V but having 250V fuses is not odd.
> These
> : > fuses are
> : > : > for overcurrent protection, and 250V is the highest nominal
> value
> : > for
> : > : > commonly available replacement fuses.
> : > :
> : > : Is there a chance that a fuse with a too low a voltage rating
> can
> : > : explode violently enough to pierce through the case? I noticed
> that
> : > : the 600V fuse in a Fluke meter was enclosed in woven fabric,
> : > possibly
> : > : for such a rupture.
> : > :
> : > : > Coffee makers require flame retardant plastic (94-V0 or V1).
> : > Standard is
> : > : > EN60335?
> : > : > Thermostat versus two thermal fuses is an individual
> : > manufacturer's design
> : > : > consideration. Either of these or other protection methods
> are
> : > valid as
> : > : > long as all of these test in the standard(s) can be met.
> : > :
> : > : I thought a coffee maker would be required to have a backup
> means of
> : > : shutting off the current in case the bimetal thermostat failed
> : > because
> : > : back in the 1970s or 1980s there was a big lawsuit against GE
> when
> : > : thermostats in some of its coffee makers failed and caused
> fires.
> : >
> : > I've had the delightful experience (~1980) of being in a computer
> lab
> : > next to an office where someone left one of those things going,
> when
> : > they left for the day. An unforgettable experience...by the time
> we
> : > could smell the smoke in the lab, the office was completely
> engulfed
> : > in flames.
> : >
> : > Are they really any safer, now? Seeing the efforts big business
> has
> : > been making to remove government oversight where it can, I'm not
> : > terribly confident about that.
> :
> : UL isn't government.
>
> Never said they were. UL doesn't make the laws, you know? What I'm
> saying, is that big business always has, and always will try to make
> an endrun around the rules, if it seems profitable, especially if it
> looks like no one will ever catch them.
>
> : From my experience (mostly residential lighting
> : equipment), I haven't noticed any relaxation of standards for fire
> or
> : electrical safety. If anytthing, It has been just the opposite.
> : Competition appears to be good for UL. Manufacturers have options
> including
> : ETL and CSA (Canadian Standards Association) and others so there are
> : alternatives. That helps costs and speed of testing. They all test
> to the
> : same standards. Some lighting equipment standards are now
> tri-national (US,
> : Canada and Mexico).
>
> Even if UL or some other agency has tested the products, there is
> still room for poor QA...and some people cheat, when it comes to
> keeping to the standards, too. Just because something you're familiar
> with doesn't appear to have any problems, doesn't mean there aren't
> any, either.

Of course. But there are data. Injuries and deaths from electrical shock
and fires for one. These have remained just about constant even though the
population has increased and has become less aware of electrical hazards (my
view). The CPSC opened an investigation of electrical/lighting fires last
year and is even paying a $50 "bounty" to fire departments to file reports.
Nothing significant so far.

What I see as the main problem at the moment is fake and counterfeited UL
(and other) marks placed on products, mostly imported, that haven't been
inspected or built to standards. Major manufacturers are paying extra to
CSA, for example, to do "dock" inspections overseas to ensure that what's in
the container is what they ordered including proper standards marking.

But where does the fake stuff end up -- on the internet, in "dollar" stores?
I don't know.

TKM

not i

2005-12-21, 12:21 pm

On Wed, 14 Dec 2005 11:53:11 -0600, "Leo Yaus" <Leo.Yaus@salom.com>
wrote:

>ETL certification is valid. Whether to use UL or CSA or ETL is a matter of
>cost, schedule, customer service, and factory location (proximity of facotry
>to service provider affects FUS [follow-up service] costs).
>ETL would require samples and documentation.
>CE is just a mark, not an organization. ETL (like UL and many others) can
>provide services permitting usage of the CE mark.
>Your meter rated at 500V but having 250V fuses is not odd. These fuses are
>for overcurrent protection, and 250V is the highest nominal value for
>commonly available replacement fuses.

Many 600 volt fuses are available. The meter I use has 600 volt fuses
and they are readily available in the area I live.

>Coffee makers require flame retardant plastic (94-V0 or V1). Standard is
>EN60335?
>Thermostat versus two thermal fuses is an individual manufacturer's design
>consideration. Either of these or other protection methods are valid as
>long as all of these test in the standard(s) can be met.
>
>"larry moe 'n curly" <larrymoencurly@my-deja.com> wrote in message
>news:1134568031.597554.72250@z14g2000cwz.googlegroups.com...
>

larry moe 'n curly

2005-12-22, 2:21 am

not i wrote:

> Many 600 volt fuses are available. The meter I use has 600 volt fuses
> and they are readily available in the area I live.

Are 600V fuses that are no more than 3/4" long? That's all the room
there is for a fuse in my meter.

Dave Plowman (News)

2005-12-22, 6:21 am

In article <1134568031.597554.72250@z14g2000cwz.googlegroups.com>,
larry moe 'n curly <larrymoencurly@my-deja.com> wrote:
> Does ETL require actual sample products to be submitted for testing, or
> are they like CE and let manufacturers work on the honor system (I have
> a CE approved multimeter rated for use at up to 500V, but its fuses are
> rated for only 250V, unlike a UL-approved Fluke).

How do you rate a fuse for voltage? It would be a peculiar design that
would flash over between terminals even at 500 volts.

--
*There are two sides to every divorce: Yours and shit head's*

Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.

Michael A. Terrell

2005-12-22, 7:21 am

"Dave Plowman (News)" wrote:
>
> How do you rate a fuse for voltage? It would be a peculiar design that
> would flash over between terminals even at 500 volts.

Really? Then try a 32 volt automotive fuse at 500 volts. PS, make
sure you can pull the plug or kill the main braker before you grab the
fire extingisher.

--
Been there, Done that, I've got my DD214 to prove it.

Michael A. Terrell
Central Florida

Dave Plowman (News)

2005-12-22, 9:21 am

In article <43AA7EC9.717D7A11@earthlink.net>,
Michael A. Terrell <mike.terrell@earthlink.net> wrote:

[color=darkred]
> Really? Then try a 32 volt automotive fuse at 500 volts. PS, make
> sure you can pull the plug or kill the main braker before you grab the
> fire extingisher.

Really? Even an 1 1/4" 'automotive' fuse?

--
*Why is it considered necessary to screw down the lid of a coffin?

Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.

Bud--

2005-12-22, 2:21 pm

Dave Plowman (News) wrote:
> In article <43AA7EC9.717D7A11@earthlink.net>,
> Michael A. Terrell <mike.terrell@earthlink.net> wrote:
>
>
>
>
>
>
> Really? Even an 1 1/4" 'automotive' fuse?
>

The US old style glass tube automotive fuses when burned open won't
flash over at 500 volts. But if connected to a 500 volt circuit, when
they open the melting metal will likely vaporize and the conductive
plasma created will continue the conduction. The energy released would
likely cause the fuse to explode - not acceptable for most users. On
high available current circuits the plasma could go end to end causing
conduction for a relatively long period. The arc can vaporize more metal
feeding the plasma. This can cause a large explosion with flying shrapnel.

US fuses have not only a voltage rating but a rating for the maximum
current the fuse will interrupt. If the circuit has an available fault
current higher than the fuse interrupt rating the fuse can also explode,
even though the fuse is used within its voltage rating. I expect you
have the same thing over the pond.

Multimeters are rated for where in a power circuit they can be used,
like downstream from a panel (lower avalilable fault current) or on
service wires (high available fault current). This is based on the
design as in the paragraph above. I believe this is an IEC standard.

bud--

Rich Grise

2005-12-22, 2:21 pm

On Thu, 22 Dec 2005 09:04:55 +0000, Dave Plowman (News) wrote:

> In article <1134568031.597554.72250@z14g2000cwz.googlegroups.com>,
> larry moe 'n curly <larrymoencurly@my-deja.com> wrote:
>
> How do you rate a fuse for voltage? It would be a peculiar design that
> would flash over between terminals even at 500 volts.

"Voltage Rating
The maximum voltage at which a fuse is designed to operate. Exceeding
the voltage rating of a fuse impairs its ability to clear an overload or
short circuit safely. Fuse can be used at any voltage below the fuse
voltage rating; a 250V fuse can be used in 125V circuits. Voltage
ratings are assumed to be for AC unless specifically labeled as DC."

-- http://www.circuitprotection.ca/fus...l#VoltageRating

Cheers!
Rich

Bud--

2005-12-22, 2:21 pm

Bud-- wrote:
> Dave Plowman (News) wrote:
>
>
> The US old style glass tube automotive fuses when burned open won't
> flash over at 500 volts. But if connected to a 500 volt circuit, when
> they open the melting metal will likely vaporize and the conductive
> plasma created will continue the conduction. The energy released would
> likely cause the fuse to explode - not acceptable for most users. On
> high available current circuits the plasma could go end to end causing
> conduction for a relatively long period. The arc can vaporize more metal
> feeding the plasma. This can cause a large explosion with flying shrapnel.
>
> US fuses have not only a voltage rating but a rating for the maximum
> current the fuse will interrupt. If the circuit has an available fault
> current higher than the fuse interrupt rating the fuse can also explode,
> even though the fuse is used within its voltage rating. I expect you
> have the same thing over the pond.
>
> Multimeters are rated for where in a power circuit they can be used,
> like downstream from a panel (lower avalilable fault current) or on
> service wires (high available fault current). This is based on the
> design as in the paragraph above. I believe this is an IEC standard.
>

More particularly related to voltage:
When a fuse opens there will be an arc. The arc will have a voltage
across it. 32 volts will not support a very long arc. 500 volts will
suport a much longer arc and will be a lot harder to extinguish. As fuse
material is vaporized (as opposed to just ionized air) the resistance of
the arc will go down and an arc with a voltage drop of 500 volts across
it will increase and be even harder to extinguish.

Spehro Pefhany

2005-12-22, 3:21 pm

On Thu, 22 Dec 2005 12:09:38 +0000 (GMT), the renowned "Dave Plowman
(News)" <dave@davenoise.co.uk> wrote:

>In article <43AA7EC9.717D7A11@earthlink.net>,
> Michael A. Terrell <mike.terrell@earthlink.net> wrote:
>
>
>
>Really? Even an 1 1/4" 'automotive' fuse?

The interrupting capacity of a typical 1.25" Fast-Acting 3AG fuse at
250V is MUCH lower than at 125VAC. They will interrupt 10kA at 125V,
but only more like THIRTY-FIVE amps at 250V. Check out the data
sheets.

Put them in a situation where they can see thousands of amperes fault
current @240V and they can and often do EXPLODE, rupturing the glass
and sending fragments everywhere.

Of course the 20mm types are worse again.

That's why Fluke multimeters use a much larger fuse.

During failure of the 3AG type fuses, the melted metal ionizes inside
the fuse and allows an arc to form directly from one end cap to the
other, which has very low impedance (low voltage drop, but lots of
watts for such a small enclosed space).

Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

Ralph Mowery

2005-12-22, 3:21 pm

"Dave Plowman (News)" <dave@davenoise.co.uk> wrote in message
news:4ddd2baf50dave@davenoise.co.uk...
> In article <1134568031.597554.72250@z14g2000cwz.googlegroups.com>,
> larry moe 'n curly <larrymoencurly@my-deja.com> wrote:
>
> How do you rate a fuse for voltage? It would be a peculiar design that
> would flash over between terminals even at 500 volts.
>
>
All fuses (of any qulaity) are rated for a maximum voltage. Also not usualy
in big letters they will have a maximum current they can inturrupt. While
looking at the physical size of them, they all look the same. I don't know
what the differance is in them, but there must be. I was in a class put on
by one of the fuse makers. They said that at one time one of the selling
points for so many differant kinds of fuses it that they are made for a
specific purpose. Now they have reversed the thinking (selling point) that
one fuse will replace many fuses that are similar.

It is really interisting to watch the Fluke meter film on using the wrong
fuse in a circuit.
Nice demonstration of what can hapen if you hook you meter across the
circuit while in a current or ohm range when you really mean to measuer the
voltage.

At work I look in the cabinet with fuses and see about 10 differant fuses
that are almost the same size and ratings. Some will have slightly
differant tips on them so you can not use them in the some fuse holders.
Really bad to have to stock so many differant kinds.

Rich Grise

2005-12-22, 4:21 pm

On Thu, 22 Dec 2005 13:33:39 -0500, Spehro Pefhany wrote:

> On Thu, 22 Dec 2005 12:09:38 +0000 (GMT), the renowned "Dave Plowman
> (News)" <dave@davenoise.co.uk> wrote:
>
>
> The interrupting capacity of a typical 1.25" Fast-Acting 3AG fuse at
> 250V is MUCH lower than at 125VAC. They will interrupt 10kA at 125V,
> but only more like THIRTY-FIVE amps at 250V. Check out the data
> sheets.
>
> Put them in a situation where they can see thousands of amperes fault
> current @240V and they can and often do EXPLODE, rupturing the glass
> and sending fragments everywhere.
>
> Of course the 20mm types are worse again.
>
> That's why Fluke multimeters use a much larger fuse.
>
> During failure of the 3AG type fuses, the melted metal ionizes inside
> the fuse and allows an arc to form directly from one end cap to the
> other, which has very low impedance (low voltage drop, but lots of
> watts for such a small enclosed space).
>

I have a couple of fuse stories. :-)

One is, I've seen 32V fuses used in a 240V circuit explode and blow
the cap off the holder, half-way across the factory floor.

One time, in the USAF, some guy in the shop ordered a 15A fuse, but
somebody made a typo in the stock number or something, because they
sent a 15A, 15,000V fuse. It was just like a standard 3AG, but it
was about 3" in diameter and about 12" long. The ends were copper,
and it was filled with sand. Nobody knew what to do with it, so we
took it apart. Inside, down the middle of the sand, was a ceramic
rod which looked like it had been extruded through an asterisk-
shaped die. Wrapped in a very loose helix around this (like,
looser than one turn per diameter) were five very fine silvery-
colored wires, the fuse element itself. The glass tube had about
about a 3/8" wall. It was quite fascinating. The sand, I guess,
was just plain old ordinary sand.

It was kinda kewl. :-)

Cheers!
Rich

Michael A. Terrell

2005-12-22, 11:21 pm

"Dave Plowman (News)" wrote:
>
> In article <43AA7EC9.717D7A11@earthlink.net>,
> Michael A. Terrell <mike.terrell@earthlink.net> wrote:
>
>
> Really? Even an 1 1/4" 'automotive' fuse?
>
> --
> *Why is it considered necessary to screw down the lid of a coffin?
>
> Dave Plowman dave@davenoise.co.uk London SW
> To e-mail, change noise into sound.

http://www.bussmann.com/ & http://www.littelfuse.com/ have a lot of
information on the proper use of fuses.
--
Been there, Done that, I've got my DD214 to prove it.

Michael A. Terrell
Central Florida

Pooh Bear

2005-12-23, 12:21 am

Spehro Pefhany wrote:

> On Thu, 22 Dec 2005 12:09:38 +0000 (GMT), the renowned "Dave Plowman
> (News)" <dave@davenoise.co.uk> wrote:
>
>
> The interrupting capacity of a typical 1.25" Fast-Acting 3AG fuse at
> 250V is MUCH lower than at 125VAC. They will interrupt 10kA at 125V,
> but only more like THIRTY-FIVE amps at 250V. Check out the data
> sheets.
>
> Put them in a situation where they can see thousands of amperes fault
> current @240V and they can and often do EXPLODE, rupturing the glass
> and sending fragments everywhere.
>
> Of course the 20mm types are worse again.
>
> That's why Fluke multimeters use a much larger fuse.
>
> During failure of the 3AG type fuses, the melted metal ionizes inside
> the fuse and allows an arc to form directly from one end cap to the
> other, which has very low impedance (low voltage drop, but lots of
> watts for such a small enclosed space).

Fuses to the IEC specs have a rupture current rating.

L = low breaking capacity.
H= high breaking capacity.

E.g T300mAL meaning T = time delay ( 'slo blo' )300mA - Low breaking
capacity.

Graham

Pooh Bear

2005-12-23, 12:21 am

Rich Grise wrote:

> On Thu, 22 Dec 2005 13:33:39 -0500, Spehro Pefhany wrote:
>
>
> I have a couple of fuse stories. :-)
>
> One is, I've seen 32V fuses used in a 240V circuit explode and blow
> the cap off the holder, half-way across the factory floor.
>
> One time, in the USAF, some guy in the shop ordered a 15A fuse, but
> somebody made a typo in the stock number or something, because they
> sent a 15A, 15,000V fuse. It was just like a standard 3AG, but it
> was about 3" in diameter and about 12" long. The ends were copper,
> and it was filled with sand. Nobody knew what to do with it, so we
> took it apart. Inside, down the middle of the sand, was a ceramic
> rod which looked like it had been extruded through an asterisk-
> shaped die. Wrapped in a very loose helix around this (like,
> looser than one turn per diameter) were five very fine silvery-
> colored wires, the fuse element itself. The glass tube had about
> about a 3/8" wall. It was quite fascinating. The sand, I guess,
> was just plain old ordinary sand.
>
> It was kinda kewl. :-)

A lot of those measures are about arc extinguishing.

Must be tricky @ 15kV though !

Graham

Rich Grise

2005-12-23, 1:21 am

On Fri, 23 Dec 2005 03:58:11 +0000, Pooh Bear wrote:
> Rich Grise wrote:
....
>
> A lot of those measures are about arc extinguishing.
>
> Must be tricky @ 15kV though !
>
> Graham

I think it'd be fun to blow one and watch! To see if it actually
melts the sand, and how that ceramic form would stand up, and stuff
like that.

Unfortunately, this is the sport of the kind of kings who have a
15 KV 20A power supply lying around in the junque box. ;-P

Cheers!
Rich

Jasen Betts

2005-12-23, 5:21 am

> How do you rate a fuse for voltage? It would be a peculiar design that
> would flash over between terminals even at 500 volts.

when the little cylinder is full of metal vapor it takes less than 500 volts
to maintain the arc for a few seconds especially if that voltage is DC.

Bye.
Jasen

John M. Hansen

2005-12-23, 9:21 am

Working in a plant with a two line three phase 13,200 volt 200 amp
supply,
We used mostly circuit breakers, but there were fuses on the auxiliary
supplies
that provided power to the transformers that controlled the switchgear.
When these fuses blew, the sand did not melt. It simply quenched the
arc.
The ceramic did not melt either, but it might show 'stains. from the melting
fuzewire.
Occasionally - if the cause were not obvious, we would take the fuse
apart
to see what had made it blow.
Best wishes, and Merry Christmas,
John M Hansen

> I think it'd be fun to blow one and watch! To see if it actually
> melts the sand, and how that ceramic form would stand up, and stuff
> like that.
>
> Unfortunately, this is the sport of the kind of kings who have a
> 15 KV 20A power supply lying around in the junque box. ;-P
>
> Cheers!
> Rich
>

Don Klipstein

2005-12-24, 1:21 pm

In <Ewdqf.177576$qk4.80791@bgtnsc05-news.ops.worldnet.att.net>, TKM wrote:

>What I see as the main problem at the moment is fake and counterfeited UL
>(and other) marks placed on products, mostly imported, that haven't been
>inspected or built to standards. Major manufacturers are paying extra to
>CSA, for example, to do "dock" inspections overseas to ensure that
>what's in the container is what they ordered including proper standards
>marking.
>
>But where does the fake stuff end up -- on the internet, in "dollar"
>stores? I don't know.

I have been gaining this impression that dollar stores get a lot of
stuff that is fake in one way or another.
I have had a dollar store compact fluorescent lamps burn out in an
uncomfortably spectacular manner a few minutes after I started running it.
Also I have heard of others having spectacular failures of dollar store
compact fluorescent lamps, including one that went "pop" 3 times
in the process of burning out.

And also fakes in matters other than safety - how about those
flashlights that say they never need batteries - shake to recharge? In my
expereince, the $2 dollar-store version (in 2 different packages now yet!)
has a fake magnet, a shorted coil, and non-rechargeable "coin style"
batteries.

Maybe I will send the FTC a dollar store compact fluorescent lamp that
produces somewhere around 30% of its claimed light output, in its package
that claims 1580 lumens and "light of a 100 watt bulb". I have yet to see
a dollar store compact fluorescent lamp meet a light output claim. Some
dollar store compact fluorescent lamps also claim "soft warm white light"
but actually glow a bluish "daylight" color.

- Don Klipstein (don@misty.com)

Don Klipstein

2005-12-24, 1:21 pm

In article <4ddd2baf50dave@davenoise.co.uk>, Dave Plowman (News) wrote:
>In article <1134568031.597554.72250@z14g2000cwz.googlegroups.com>,
> larry moe 'n curly <larrymoencurly@my-deja.com> wrote:
>
>How do you rate a fuse for voltage? It would be a peculiar design that
>would flash over between terminals even at 500 volts.

Vaporized metal can sustain an arc that long (I am assuming length
of an AGC style fuse) with even less voltage than that. Try seeing how
long an arc you can draw with an arc welder at merely 30-40 volts or so,
and then imagine what 500 or even 250 volts can do. I once had an arc
almost an inch long between 12 AWG copper wires with only 2-3 amps at 120
volts during an experiment trying to see the spectrum of a copper vapor
arc.

Also, fuses often have a lower voltage rating for DC than for AC.

- Don Klipstein (don@misty.com)

Don Klipstein

2005-12-24, 2:21 pm

In article <4ddd3c983fdave@davenoise.co.uk>, Dave Plowman (News) wrote:
>In article <43AA7EC9.717D7A11@earthlink.net>,
> Michael A. Terrell <mike.terrell@earthlink.net> wrote:
>
>
>Really? Even an 1 1/4" 'automotive' fuse?

May work OK with AC voltage that high, especially if it is a lower
current fuse - but it has not been tested and certified to be reliably
safe/effective in such use. May even usually work OK. May work OK when
you try it, and then your luck may run out sometime later if that fuse is
somewhere other than under your eyes or sometime when you (or worse still
others) don't know where the power disconnect and the fire extinguisher are.

- Don Klipstein (don@misty.com)

Joerg

2005-12-24, 9:21 pm

Hello Don,

> Maybe I will send the FTC a dollar store compact fluorescent lamp that
> produces somewhere around 30% of its claimed light output, in its package
> that claims 1580 lumens and "light of a 100 watt bulb". I have yet to see
> a dollar store compact fluorescent lamp meet a light output claim. Some
> dollar store compact fluorescent lamps also claim "soft warm white light"
> but actually glow a bluish "daylight" color.
>

I don't buy at Dollar stores but I did buy a six-pack of CFL for under
$6 at Home Depot. So that's under a dollar a pop. They work great,
unlike many of the more expensive ones I had. The light is spectrally
more filament-like and they start instantly, just like a bulb.

Merry Christmas, Joerg

http://www.analogconsultants.com

Joerg

2005-12-24, 9:21 pm

Hello Don,

> Vaporized metal can sustain an arc that long (I am assuming length
> of an AGC style fuse) with even less voltage than that. Try seeing how
> long an arc you can draw with an arc welder at merely 30-40 volts or so,
> and then imagine what 500 or even 250 volts can do. I once had an arc
> almost an inch long between 12 AWG copper wires with only 2-3 amps at 120
> volts during an experiment trying to see the spectrum of a copper vapor
> arc.
>
> Also, fuses often have a lower voltage rating for DC than for AC.
>

It is also a matter of energy to be absorbed. A 1A fuse blowing in a 24V
circuit because the current gradually sauntered towards 2A is one thing,
the same fuse in a 240V mains circuit experiencing a sudden dead short
on the other side is quite another. The breaker for such circuits can be
designed for 16A or more depending on where you are in Europe.

I've had fuses spewing their glass and sand all over the place and
leaving nasty scorch marks. I don't think running fuses above their
maximum voltage rating is a good idea. If a manufacturer does it anyway
and something happens the lawyers will be all over them.

Regards, Joerg

http://www.analogconsultants.com

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