Interrupt ratings are in amps, not volts. The 11A/1000V fuse in Fluke handhelds has an interrupt rating of 20,000 amps.
They're more expensive than the 3AGs (or 5x20s) found in cheap meters. Beware of the cheap ones if measuring AC circuits, and don't believe their CAT ratings. A 1000V CAT II meter needs to have an 84 A interrupt rating at its rated voltage. The test source is 1000 V/12 ohms. A standard 3AG has a 200 A (5x20s have 80 A) rating at 250 VAC. So, when you see a
cheap meter with a CAT II rating, a 750 VAC setting, and it uses 3AG fuse, they're lying to you. If it's a 5x20 fuse, it's not even safe at 250V, forget about 750V.
Even a low end Fluke is CAT III/1000V, which requires a minimum 4000 A interrupt rating. But the fuses are $10, not $1.