What is the difference beatween 250V marced FUSE and 1000V?

[sorin]

what is the difference between  250V and 1000V  marked FUSE?
maybe the minimum separation distance when the fuse blow...

[Wytnucls]

'The voltage rating of the fuse must be greater than or equal to the circuit voltage.
Because the fuse has such low resistance, the voltage rating becomes critical only when the fuse is trying to open.
The fuse must be able to open quickly, extinguish the arc after the fuse element has melted and prevent the system open-circuit voltage from restriking across the open fuse element.' (Cooper Bussmann)

[ejeffrey]

Yes. When operating normally the voltage over the fuse will obviously be small.  The fuse rating is the maximum voltage the fuse is rated to interrupt.

[sorin]

thanks both for answer;
I'm not asking why is important the rated voltage on a fuse "To prevent arc you need just a distance of a couple of mm."
The question is why (I mean in mechanics construction) fuses with same physical dimension are rated with different voltage
what is different in 1000v fuse??

[Wytnucls]

Have a look at this:

[Neilm]

Nice video - showing real sized fuses for a change.

what is different in 1000v fuse??

Firstly 1000V fuses are generally bigger. As mentioned in the video, the fuses are filled with sand. The higher breaking capacity fuses will have different sand in them which will quench the extra energy. This is why glass fuses are not used in reputable multi-meters. They don't have sand in them and as the fuse vaporises a high energy source will have enough behind it to continue the arc through the vapourised metal

Neil

[sorin]

see this