Quite so.

As you mention bombs...


When fusing ordnance one defines the currents for electric fuses as


An "All fire" current  above which all devices should detonate, any that do not are dud.


A "No fire" current below which no  devices detonate,  any fuses that do should not have passed factory inspection before the thing was assembled with the main charge.


Something safely less than the No fire current is used to put the "primed" lights on  and give confidence the circuit is intact.


Something quite a bit more than the All fire current is used when the buttons are pressed.


There is indeed a range of currents, in many cases more than an order of magnitude in fact,  which you should try and avoid dwelling on, that are totally indeterminate, as not all devices have exactly the same thickness of fuse element, or the same mass of primer to heat up. If for any reason you do you supply a current in the indeterminate range you may have an unexpected event after an unknown delay.?

The penalty of getting it wrong may not be as bad with our sort of fuses and breakers , but the physics and variation in manufacture means the same ideas apply - certainly some devices will survive a current higher than the one printed on it, but how many - well who can say.

In some case we do not care. Inside a lot of domestic electronic kit, fuses are used that are thin glass walled efforts,  the mains short circuit current is likely to not just melt the wire but also destroy the glass tube. But if the outer enclosure provides shrapnel and blast containment we might not care, so long as the current is interrupted, so we can use a fuse with an apparently inadequate maximum rupture rating. (if you try and repair the thing, you need to remove the shards of glass or ceramic and so on carefully before restarting, and take great care if powering up open top )

Mike.

Quite so.

As you mention bombs...


When fusing ordnance one defines the currents for electric fuses as


An "All fire" current  above which all devices should detonate, any that do not are dud.


A "No fire" current below which no  devices detonate,  any fuses that do should not have passed factory inspection before the thing was assembled with the main charge.


Something safely less than the No fire current is used to put the "primed" lights on  and give confidence the circuit is intact.


Something quite a bit more than the All fire current is used when the buttons are pressed.


There is indeed a range of currents, in many cases more than an order of magnitude in fact,  which you should try and avoid dwelling on, that are totally indeterminate, as not all devices have exactly the same thickness of fuse element, or the same mass of primer to heat up. If for any reason you do you supply a current in the indeterminate range you may have an unexpected event after an unknown delay.?

The penalty of getting it wrong may not be as bad with our sort of fuses and breakers , but the physics and variation in manufacture means the same ideas apply - certainly some devices will survive a current higher than the one printed on it, but how many - well who can say.

In some case we do not care. Inside a lot of domestic electronic kit, fuses are used that are thin glass walled efforts,  the mains short circuit current is likely to not just melt the wire but also destroy the glass tube. But if the outer enclosure provides shrapnel and blast containment we might not care, so long as the current is interrupted, so we can use a fuse with an apparently inadequate maximum rupture rating. (if you try and repair the thing, you need to remove the shards of glass or ceramic and so on carefully before restarting, and take great care if powering up open top )

Mike.