HRC Fuses

[Kiriakos-GR]

Mains... mains... no, can't see mains there. Can anyone else?

I love practical facts as proofs , and so the trillions of electrical devices that we all have plugged on Mains 24/24 with glass fuses , does not explode .. does not receive dangerous  8000V pulses ... does not cause disasters and waves ...

And the permanent problem of mains its not the over-voltage ... the opposite bothers us !!  

And so I am less passionate about the ultimate standards , because I do not see them to have any effect in the real life !!

I have exchange lots of burned fuses from all sort of devices , there is nothing tragic in a burned fuse.
Some they will burn just the wire , and the glass stays clean.
Some they will burn and they will become smokey .
And that's it .

Lets take a breath and speak a bit about human ages and advices.

The parents as grownups  they usually enlarge the risks , so the fear to protect the Kids ,
because they are unable to understand the details.  
In this specific forum the members  age are not viewable , and so its common most people to think that they communicate with smaller persons in age , and they doing the known " parents example " so to protect them .
Recently we had even an example of one young kid who tried to measure an electrical fence !!

And so I suggest to all to define their communication protocol .
Father to son ?
Technician to  Technician ?
Chef Technician to  Technician ?
Master God of technicians to  every one ?

I am more confused than all of you as an non natural English speaking person,
because i am unable to detect easily at list , irony - flames - sarcasm - black humor ..
And I do have hard times to follow this conversation.  

And so I will say so far what I have understand.
cybergibbons you have right the glass fuses are faster ...

Uncle Vernon you are overreacting about how the fuses die , usually they die with not that's much noise.  

To all I believe that all those multimeter's that had become fireworks ,
had internal issues on the PCB , that's why they had turn to carbon that easy.
The PCB lines had less clearance than the clearance of an single glass fuse.
Or the PCB was bad quality , and by the heat become cont-active.

And so only the multimeter that lives on industrial environment needs to offer the " maximum " protection.
(what ever that is ) 

[Kiriakos-GR]

There is plenty of application other than meters that require a rapid HRC fuse.

I am dying to be informed about such examples !!

Because currently , I think that some one had set up an conspiracy by having as center the multimeter,
and the HRC Fuses as cheese , and the silly mouse will pay the what ever cost so to get them,
because of fear mostly.  

Like the sales men who trade health insurance contracts , that if you do not sign ,
all the disasters of the world , it will happen to you , the next day .  
( This is what their propaganda says at list )  

I still expect one reply , because this is the only portable example with HRC fuses that I have see so far !!

And as example that demands fast HRC only the Fluke DMM.

[Uncle Vernon]

And the permanent problem of mains its not the over-voltage ... the opposite bothers us !!  

In this part of the world  over-voltage can be a real problem. Our 240V mains (which are supposed to be now reduced to 230V) are routinely well above that figure 8pm Saturday and I'm seeing 250V. Certainly well out of a safe range for all the 220V equipment sold here. I Western Australia and remote parts of NSW it's not uncommon to see the mains reach 275V. And yes our neglected and quasi-privatised grid experiences plenty of brown-outs too. But non of this has too much bearing upon the results in a dead short situation.

I have exchange lots of burned fuses from all sort of devices , there is nothing tragic in a burned fuse.
Some they will burn just the wire , and the glass stays clean.
Some they will burn and they will become smokey .
And that's it .

But that is not always it, sure it's the most common outcome but there are plenty of times it is not the case. Hell more than a few of those garbage $50 meters don't even have fuses in-line with the current shunt. And I sure as hell don't want to be holding a meter inadvertently flashed across the mains with only a cheap glass fuse as any sort of safety margin.

And so I will say so far what I have understand.
cybergibbons you have right the glass fuses are faster ...

Nothing has been presented to suggest that a glass fuse will be the fastest thing to interrupt  potentially huge fault currents or that one would be capable of interrupting it at all.

Uncle Vernon you are overreacting about how the fuses die , usually they die with not that's much noise.  

No ever-reaction at all, the Cat III and Cat IV devices are designed to be as safe as possible during use and potential misuse. This includes using appropriate fuses for the application. All the guff about overloads of a few times has no bearing on what happen during situations where fault currents can be massive and where arcs are easily created. The HRC fuses selected by the manufacturer will be the best cost compromise solution that meets all the required ratings.

To all I believe that all those multimeter's that had become fireworks ,
had internal issues on the PCB , that's why they had turn to carbon that easy.
The PCB lines had less clearance than the clearance of an single glass fuse.
Or the PCB was bad quality , and by the heat become cont-active.

Agreed they are garbage that aren't suitable for even hobbyist use.

And so only the multimeter that lives on industrial environment needs to offer the " maximum " protection.
(what ever that is ) 

Not just in industrial environments, in any environment where mains or high energy sources are involved, however infrequent, and I'd advise hobbyist working with anything more than a couple of AA cells to consider using the same protection.
You can weld your probes onto conductors under a short! Any test instrument not rated for the environment can let go violently under severe overload.  Those HRC fuses in a quality meter ARE the quickest way of ensuring operator and device safety under in situations likely to cause fire or physical harm.

No amount of namby-pamby work method statements and procedures are going to help when the inevitable mistakes are made. Appropriate equipment with appropriate internal protection affords at least some protection when things go wrong. Whether it's to protect their users or to protect themselves from litigation, manufacturers of rated equipment have gone to a lot of effort to ensure minimisation of risk in the shortest possible time. On that basis, I will trust their judgement ahead of any random or selective reading of device specification under entirely different conditions.

The risks remain, call it over reaction if you wish.

[cybergibbons]

Nothing has been presented to suggest that a glass fuse will be the fastest thing to interrupt  potentially huge fault currents or that one would be capable of interrupting it at all.

No one has claimed it would be the fastest to act under huge fault currents. It's faster to act from 1 to 10 times overload.

[tom66]

Would it be possible to upgrade a multimeter's glass fuse and replace it with a HRC?

[cybergibbons]

Would it be possible to upgrade a multimeter's glass fuse and replace it with a HRC?

Yes, if you can find one in that size. It's not guaranteed to make the meter any safer though - if the meter manufacturer has skimped on the fuses, it's quite likely the PCB and rest of the design may not allow interruption of large fault currents.