On Tue, 23 Nov 2010 11:31:59 -0600, bud--
wrote:

wrote:
On Mon, 22 Nov 2010 10:02:11 -0600, bud--
wrote:

wrote:
As far as the UL is concerned, they don't really care because it is
NOT a safety issue. Can't cause a fire or any other damage
Maybe you are thinking of CSA.

You think UL has no concern about fuses opening in ways they are not
designed to open?

They want them to open to clear a fault.

UL also does not want fuses to fail in hazardous ways
Arcing and intermittently being open are hazardous.

Arcing at an alleged fracture point?

The arc is very tiny and totally enclosed - definitely not a safety
issue

The size of the arc is determined by the current. Arcs can generate a
lot of heat. And cause fires or deteriorate nearby connections.

OK Bozo - if there was any amount of current involved - read that as
anything aproaching even a fraction of the current the fuse is rated
for, it would NOT be intermittent - the fuse link would "fuse" - which
means melt - and open completely from the heat of the arc.

And in a cartridge fuse,(mains) the arc extinguishing filler would
look after it in short order. In automotive fuses it is MUCH more
common because of the vibration issue.
As a mechanic I found DOZENS of fuses that had simply fractured - and
MANY of them were intermittent.

Absolutely no way it could escalate into a fire safety issue.

You are just being an ass - admit it.

I haven't seen it. I spent years doing residential, commercial,
industrial service work.
I've seen a few - more in low voltage DC automotive fuses than mains
or branch circuit fuses - but I have had 2 plug fuses fail in my own
house over the last 29 years that were NOT overloads or shorts.

Can't rmember for sure, but I think both were either Buss or Gould

So for power wiring we are only talking about plug fuses. Allegedly
only 2 have failed.
2 have failed in MY panel over 30 years.

I can remember my dad mentioning several situations when he was
working as an electrician where the fuse had "failed" - not "blown"
and the neon testers used widely in the day to check for power showed
power - but a 15 watt bulb would not light.
His recommendation was if you found one fuse failed in that way in a
customer's panel, and all the fuses were the same brand - and looked
to possibly have been installed at the same time, to replace them all.
He figured a bad batch. I suspect it was temperature
cycling/vibration or whatever, possibly combined with a bad batch