Fuse: fast blown vs slow blown

I didn't know that.

How about this one?

--Winston :)

** Cos you know f*ck all about anything.

** Standard glass (fast) fuse by the look of it.

.... Phil

(...)

It's a continuing problem. Watta ya gonna do. :)

It must be ~36 times safer than a commodity GMA fuse in a multimeter application, yes?

Fluke wouldn't overcharge for that part either, surely.

--Winston

** The price is very steep.

But I expect the fuse IS safe when used in the Fluke DMMs it is specified for.

The scenario with a 0.125A fuse is nothing like the one with the 10A range fuse.

Typical 0.125A rated fast fuses have resistances of 8 to 10 ohms - which limits the fault current to a value the fuse can easily break.

A 10 amp fuse may well have a resistance of only a few milliohms, so the fault current is only limited by the resistance of the DMM's leads.

A current of 40 amps is easy enough for a small fuse to break, while one of over 4000 amps is not.

Capice?

.... Phil

(...)

We agree.

Both the 'Fluke' brand and the commodity brand are safe, I suspect.

It wouldn't shock me to learn both kinds are sourced from the same place.

We agree on that, too.

--Winston

** Yawnnnnnnnnnnnn....

** Nothing shocks a f****it like you.

** GIANT Yawwnnnnnnnnnnnnnnnnnnn

Piss off wanker.

... Phil

Coz you are in USA, not Hong Kong (ex-UK colony)! :)

-- @~@ Might, Courage, Vision, SINCERITY. / v \ Simplicity is Beauty! May the Force and farces be with you! /( _ )\ (x86_64 Ubuntu 9.10) Linux 2.6.39 ^ ^ 14:44:01 up 6 days 23:46 0 users load average: 1.00 1.01 1.05 ???! ???! ???! ???! ???! ???! ????? (CSSA):

"Man-wai Chang"

** Hey - rice muncher.

I am in Sydney, Australia.

BS1362 fuses are used in professional dimmers imported from the UK.

.... Phil

Hello, wheat muncher!

How do you tell they were really BS1362 without any printing on the fuse? So its look is unique among all fuses?

-- @~@ Might, Courage, Vision, SINCERITY. / v \ Simplicity is Beauty! May the Force and farces be with you! /( _ )\ (x86_64 Ubuntu 9.10) Linux 2.6.39 ^ ^ 17:59:01 up 7 days 3:01 0 users load average: 0.97 1.03 1.04 ???! ???! ???! ???! ???! ???! ????? (CSSA):

could be as dangerous as using a nail instead,

--
?? 100% natural

e

which

of

Nice post a couple levels up.

Meters like the Flukes are "Category" rated - 1, 2, 3. When working on high capacity services, like 1000A 480V, you really want a cat 1 meter. You won't wind up wearing it as in your previous post. The problem is not just the meter. Arc in meter causes vaporized meter leads that turns into an arc between busbars - very dangerous.

In addition to the nominal voltage you have the hazard of transients that could start an arc which will then sustain at the nominal voltage. In the US, OSHA may also take strong exception to using a meter without the right cat rating.

One of the hazards in high capacity services is available fault current, which can be 200,000A. Fuses have a rating for available fault current. The fix is to use "current limiting" fuses. For high currents they have a clearing time of under 1/4 cycle. You handle a

200,000A available location by the fuse clearing before the current increases to anything near that value. The earlier Fluke fuse is certainly current limiting. The fuse opens before the meter leads turn to plasma.

The fuse in the later link is a mere 250V - not likely a cat 1 meter. But a glass 250V GMA fuse in a meter may exceed the fault current rating for the fuse. One of the fuses in my Fluke is 0.44A and is almost certainly current limiting.

-- bud--

(...)

Thanks!

I learned about 'flashover' only very recently. Once you know about it, it's obvious.

So *that's* the '40,000 A' number in the 11A fuse ratings. I always wondered about those stunningly huge numbers.

I pointed to that fuse to show that Fluke were not undercharging for replacement parts. :) That fuse is in a 'hobby / light industrial' instrument.

That's the same package as the 11 A fuse I originally mentioned.

Ironically, I popped it measuring automotive electrical stuff. (Note to self: Don't leave meters on the bench with the probes connected to measure current!) :)

Lesson learned.

--Winston

(...)

You are so beautiful when you are angry, Phil.

--Winston :)

no, he's not angry, he's being Phil.

Jamie

I see.

--Winston

Ignore Phil. He's mentally ill, and off his medication most of the time.

--
It's easy to think outside the box, when you have a cutting torch.

** Ignore Terrell.

He's a rabid psychopath, wheelchair bound and lives in the Florida everglades in a caravan.

He knows he is gonna die a horrible death.

And it cannot come too soon for me.

... Phil

I really mis-interpreted his sentence. Apology is necessary! :)

-- @~@ Might, Courage, Vision, SINCERITY. / v \ Simplicity is Beauty! May the Force and farces be with you! /( _ )\ (x86_64 Ubuntu 9.10) Linux 2.6.39 ^ ^ 16:22:01 up 8 days 1:24 0 users load average: 1.02 1.07 1.12 ???! ???! ???! ???! ???! ???! ????? (CSSA):

The physics books I read did NOT talk about this danger. So were all the physics teachers that taught me. Maybe I fell asleep when they talked about this. In short, the "art" of choosing the right multimeter for the right job was not covered by the physics course material of my school time.

It's really lucky that I was never hurt so far when playg with hobby circuits...

--
   @~@   Might, Courage, Vision, SINCERITY.
  / v \  Simplicity is Beauty! May the Force and farces be with you!
/( _ )\ (x86_64 Ubuntu 9.10)  Linux 2.6.39
   ^ ^   16:27:01 up 8 days 1:29 0 users load average: 1.01 1.06 1.11
???! ???! ???! ???! ???! ???!
????? (CSSA):
http://www.swd.gov.hk/tc/index/site_pubsvc/page_socsecu/sub_addressesa