"David Hansen" wrote in message
...

Any fuse holder will have a rated maximum voltage.


So now you know what caused the OP's failure....

On Tue, 15 Apr 2008 13:40:10 +0200 someone who may be "Clive"
wrote this:-

So now you know what caused the OP's failure....

Nice try.


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

In article ,
David Hansen wrote:
On Tue, 15 Apr 2008 08:55:31 +0100 someone who may be charles
wrote this:-

an ordinary 1.25" cartridge fuse

What's one of those?

CPC part number: FS01458 etc.

http://cpc.farnell.com says there is no such part.

sorry, it is FF01458.


To be of any use to people the OP should have given some useful
information, such as the current rating and (perhaps) the breaking
capacity of the fuse. The physical sizes of fuses are not useful.

If the intention was to be a little more coy then whether the
dimension quoted was the length or diameter would have been useful.

--
From KT24 - in "Leafy Surrey"

Using a RISC OS computer running v5.11

On Tue, 15 Apr 2008 13:46:18 +0100 someone who may be charles
wrote this:-

http://cpc.farnell.com says there is no such part.

sorry, it is FF01458.

Thanks.

Voltage rating, AC:250V
Current, fuse rating:10A
Current, breaking capacity AC:200A


If I had inherited equipment which included a 3 kV DC supply
charging a cubic metre or so of capacitors via a couple of dozen
ordinary 200 V bulbs in series then I would have thought about such
a fuse and then replaced it with something suitable.

We don't know precisely what caused the fuse to operate, but we do
know that the fuse was unable to break the current which was flowing
at the time.



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

"
The physical size of the fuse IS important when you are considering
spark-gaps etc, which is what caused the dramatic failure in this case.

Incorrect. What is important in this respect is the breaking
capacity of the fuse. Different designs of fuse, with the same
physical dimensions, are able to reliably break different currents.


Not incorrect, some fuses have fillers in the tube to help prevent arcing at
EHT voltages. Fuses will normally have a voltage rating as well as a current
rating and type (fast blow, anti surge etc.)

Jeff

"Jeff" wrote in message
. com...

"
The physical size of the fuse IS important when you are considering
spark-gaps etc, which is what caused the dramatic failure in this case.

Incorrect. What is important in this respect is the breaking
capacity of the fuse. Different designs of fuse, with the same
physical dimensions, are able to reliably break different currents.


Not incorrect, some fuses have fillers in the tube to help prevent arcing
at EHT voltages. Fuses will normally have a voltage rating as well as a
current rating and type (fast blow, anti surge etc.)

Jeff


Even these little household fuses are filled with sand to do exactly that
job.

On Tue, 15 Apr 2008 18:18:08 +0100 someone who may be "Jeff"
wrote this:-

The physical size of the fuse IS important when you are considering
spark-gaps etc, which is what caused the dramatic failure in this case.

Incorrect. What is important in this respect is the breaking
capacity of the fuse. Different designs of fuse, with the same
physical dimensions, are able to reliably break different currents.


Not incorrect, some fuses have fillers in the tube to help prevent arcing at
EHT voltages.

Incorrect. The "fillers" (and indeed the nature of the fuse element)
are one of the determinants of the breaking capacity.

EHT is not a term which is defined in the usual sources. Perhaps you
could tell us what your definition is?

Fuses will normally have a voltage rating as well as a current
rating and type (fast blow, anti surge etc.)

The voltage was stated in the CPC information I was eventually able
to quote. Readers may have noted that none of the information was
for DC.


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

"David Hansen" wrote in message
...
On Tue, 15 Apr 2008 18:18:08 +0100 someone who may be "Jeff"
wrote this:-

The physical size of the fuse IS important when you are considering
spark-gaps etc, which is what caused the dramatic failure in this case.

Incorrect. What is important in this respect is the breaking
capacity of the fuse. Different designs of fuse, with the same
physical dimensions, are able to reliably break different currents.


Not incorrect, some fuses have fillers in the tube to help prevent arcing
at
EHT voltages.

Incorrect. The "fillers" (and indeed the nature of the fuse element)
are one of the determinants of the breaking capacity.


Incorrect, filling a fuse body with sand provides additional protection
against arcing in an overcurrent situation.

"Clive" wrote in message
...

"David Hansen" wrote in message
...
On Tue, 15 Apr 2008 18:18:08 +0100 someone who may be "Jeff"
wrote this:-

The physical size of the fuse IS important when you are considering
spark-gaps etc, which is what caused the dramatic failure in this
case.

Incorrect. What is important in this respect is the breaking
capacity of the fuse. Different designs of fuse, with the same
physical dimensions, are able to reliably break different currents.


Not incorrect, some fuses have fillers in the tube to help prevent
arcing
at
EHT voltages.

Incorrect. The "fillers" (and indeed the nature of the fuse element)
are one of the determinants of the breaking capacity.


Incorrect, filling a fuse body with sand provides additional protection
against arcing in an overcurrent situation.


Only partially incorrect; the filler will have an effect on the breaking
current of the wire due to added thermal capacity, but that is not its
primary purpose, which is to prevent arcing. (the wire is gauge and
composition is modified to compensate for the filler).

Jeff

On Wed, 16 Apr 2008 08:54:23 +0200 someone who may be "Clive"
wrote this:-

Incorrect, filling a fuse body with sand provides additional protection
against arcing in an overcurrent situation.

Glad we got there in the end. The fuse failed to break the current.
The mechanism by which it failed to break the current was that an
arc formed, which is the way fuses which fail to break the current
fail.

We don't know why the fuse operated and failed to break the current.
It may just have expired through old age, or there may have been a
large current flowing for some reason. However, this does not change
the fact that the fuse failed to break the current. If it had broken
the current then there would have been no arc.

Circuit breakers can fail to break the current in the same way. They
can also fail to break the current because the contacts don't move
or don't move far enough.

Also, as I have said before, the fuse referred to on the web site
does not appear to be specified for DC use. It will be able to break
some current, but its capacity to break DC current is going to be
rather less then breaking AC.



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