Fuse: fast blown vs slow blown

[Phil Allison]

"Michael A. Terrell"

Man-wai Chang wrote:

** 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

 

[Man-wai Chang]

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

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!
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[Man-wai Chang]

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.

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
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[Man-wai Chang]

could be as dangerous as using a nail instead,

Good analogy!

--
@~@ 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
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[Phil Allison]

Michael A. Terrell"
Man-wai Chang wrote:


** Ignore the Terrell fuckwit..

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

He knows he is gonna die a horrible death.

And it cannot come too soon for me.




.... Phil

 

[Phil Allison]

"Man-wai Chang"

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.

** So fucking what ???

Did your physics course cover making Dim Sims ??

Or the Chinese Revolution by " Ou Flung Dung " ??



..... Phil

 

[Phil Allison]

"Man-wai Chang"

Good analogy!

** Shame you are not an analogy to anything human.




..... Phil

 

[Michael A. Terrell]

Phil Allison wrote:

Michael A. Terrell"
Man-wai Chang wrote:

** Ignore the Terrell fuckwit..

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

Liar. I do use a cane becasue of a bad knee. I live in a three
bedroom house, with a 1200 square foot shop building. I also have a one
bedroom cottage on my property. I am over one hundred of miles from the
Everglades as well.

You live in a tiny, crappy apartment filled with old stereos, and
mutilated toasters.

He knows he is gonna die a horrible death.

Is there any pleasant death? That is, other than when a loser like
you goes away?

And it cannot come too soon for me.

Not going to happen, Phil. Unless you steal enough money to carry out
your death threats.

Anyone who is on any electronics newsgroup for very long sees what a
shrieking psychopath you are when you're off your medication.


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

 

[Phil Allison]

"Michael A. Terrell

Phil Allison wrote:

** Ignore the Terrell fuckwit..

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

He knows he is gonna die a horrible death.

And it cannot come too soon for me.


Not going to happen, Phil.

** You are one sick man.

Mentally and physically.

A raving criminal psychopath of the gutless scumbag kind.

You imminent death will be cause for great celebration.




...... Phil

 

[Jamie]

Man-wai Chang wrote:

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.


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...

don't feel so bad, it used to be an accepted practice to use your index

finger and thumb as a go-no-go voltage test.. I know some one that has
one of the first NEC or what ever they called it back then, books, with
that statement in it.

Jamie

 

[Phil Allison]

"Jamie the fuckwit radio ham"
Man-wai Chang = Dim as he Sim

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...

** So fucking what ???

Did your physics course cover making Dim Sims ??

Or the Chinese Revolution by " Ou Flung Dung " ??

You pathetic Wang Ker !!!




..... Phil

 

[Man-wai Chang]

Did your physics course cover making Dim Sims ??
Or the Chinese Revolution by " Ou Flung Dung " ??
You pathetic Wang Ker !!!

When are you going to write a book on circuitries?

--
@~@ 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
^ ^ 22:34:02 up 8 days 7:36 0 users load average: 1.09 1.05 1.05
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[Phil Allison]

"Man-wai Chang" <toylet.toylet@gmail.com>

** See the reference to shit head.

When are you going to write a book on circuitries?

** When are you going to stick you fat head up a dead dragon's arse ??

BTW:

Still no idea what Confucius meant by:

" The quick brown fox jumps over the lazy dog "

Wang Kerr.


.... Phil

 

[Man-wai Chang]

** When are you going to stick you fat head up a dead dragon's arse ??

dragon? you meant this one: http://sites.google.com/site/changmw/

Still no idea what Confucius meant by:
" The quick brown fox jumps over the lazy dog"

That's not a chinese idiom as far as I knew.... you have the chinese words?

--
@~@ 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
^ ^ 00:14:01 up 8 days 9:16 0 users load average: 1.04 1.14 1.12
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[Smitty Two]

In article <is8d6d$alq$1@dont-email.me>,
Man-wai Chang <toylet.toylet@gmail.com> wrote:

** When are you going to stick you fat head up a dead dragon's arse ??

dragon? you meant this one: http://sites.google.com/site/changmw/

Still no idea what Confucius meant by:
" The quick brown fox jumps over the lazy dog"

That's not a chinese idiom as far as I knew.... you have the chinese words?

It's a typing exercise. Contains every letter of the alphabet. Stop
taking Phil seriously.

 

[Man-wai Chang]

It's a typing exercise. Contains every letter of the alphabet. Stop
taking Phil seriously.

Thanks. I wonder whether he/she met a REAL dragon before!

--
@~@ 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
^ ^ 00:34:01 up 8 days 9:36 0 users load average: 1.10 1.08 1.09
不借貸! 不詐騙! 不援交! 不打交! 不打劫! 不自殺! 請考慮綜援 (CSSA):
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[bud--]

On Jun 1, 1:30 pm, Winston <Wins...@BigBrother.net> wrote:

bud-- wrote:

(...)

Nice post a couple levels up.

Thanks!

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.

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

Called arc-flash in US. The hazard isn't always obvious. One of the
smartest electricians I have run across wanted to measure the motor
current in a food plant. The motor starters were in a motor control
center, which is a frame with many motor starter modules - busbar feed
in back. He defeated the door interlock, opened the module door and
put a clamp-on ammeter on one of the contactor motor wires - all
absolutely routine. No one knows what happened - the guess was there
was a loose screw. In any case there was an arc-flash. He had bad
burns, some from vaporized copper condensing on his skin. He spent a
lot of time in the hospital with multiple plastic surgeries. But he
survived. You can be killed from burns, concussion from the explosion,
shrapnel.

These days to be OSHA compliant and make the same measurement you
might have to wear an arc-flash suit. OSHA interest in arc-flash is
relatively recent. Some related equipment issues are now in the US-
NEC.

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 thefuseclearing before the current
increases to anything near that value. The earlier Flukefuseis
certainly current limiting. Thefuseopens before the meter leads turn
to plasma.

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

A commonly available Bussmann FRN 20A fuse is "current limiting" and
rated for 200,000A available fault current. But much bigger.

--
bud--

 

[Rich Grise]

Phil Allison wrote:

"Man-wai Chang"

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.

** So fucking what ???

Did your physics course cover making Dim Sims ??

Or the Chinese Revolution by " Ou Flung Dung " ??

Cow Dung Flung?

http://www.youtube.com/watch?v=FQMbXvn2RNI
Pay particular attention at 3:40

Cheers!
Rich

 

[Rich Grise]

Jamie wrote:

Man-wai Chang wrote:

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.


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...

don't feel so bad, it used to be an accepted practice to use your index
finger and thumb as a go-no-go voltage test.. I know some one that has
one of the first NEC or what ever they called it back then, books, with
that statement in it.

The way I heard that was that with the one hand in the equipment

manipulating the probe, and the other hand in your pocket or tied behind
your back, that sometimes people will ground their thumb or more likely
little (pinkie) finger, so that when they _do_ get zapped, it only burns
their hand and doesn't go through their heart and cause fibrillation or
cardiac arrest.

Hope This Helps!
Rich

 

[Winston]

bud-- wrote:

On Jun 1, 1:30 pm, Winston<Wins...@BigBrother.net> wrote:

(...)

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

Called arc-flash in US.

Yes.

The hazard isn't always obvious.

I meant 'conceptually speaking'. At higher voltage levels,
a lot more objects look like conductors. At higher current
levels, a lot more objects *continue* to be conductors.
When we combine higher voltage with higher current, it is
amazing that more electricians aren't injured.

I spent my career working on the really low-power
end of the spectrum and never thought about high-power
hazards. I recently helped troubleshoot a 208 V
3 phase system and thought I was in the 'big leagues'!

Um. Turns out I wasn't.

One of the
smartest electricians I have run across wanted to measure the motor
current in a food plant. The motor starters were in a motor control
center, which is a frame with many motor starter modules - busbar feed
in back. He defeated the door interlock, opened the module door and
put a clamp-on ammeter on one of the contactor motor wires - all
absolutely routine. No one knows what happened - the guess was there
was a loose screw. In any case there was an arc-flash. He had bad
burns, some from vaporized copper condensing on his skin. He spent a
lot of time in the hospital with multiple plastic surgeries. But he
survived. You can be killed from burns, concussion from the explosion,
shrapnel.

That's one of those situations where living can be worse
than dying.

These days to be OSHA compliant and make the same measurement you
might have to wear an arc-flash suit. OSHA interest in arc-flash is
relatively recent. Some related equipment issues are now in the US-
NEC.

http://www.texsoinstruments.com/arc-flash-suits

I see that this company makes several suits that apparently
comply to NFPA 70E but only their most expensive is said to
protect against shrapnel and none are said to protect
against plasma (reasonably enough!).
I guess 'something' is better than nothing.

(...)

(Snip fuse 'fault current rating')

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


A commonly available Bussmann FRN 20A fuse is "current limiting" and
rated for 200,000A available fault current. But much bigger.

Whoa.

--Winston