wytnucls, you're still getting it wrong.
You banged on about the UT71E not going to have anything happen to it if you measure amps. Okay.
But did you know what happens if you attempt to measure voltage with the leads in amps? BOOM! If it was 600V? Your supposedly very safe glass fuse BLOWS UP! I have seen glass fuses break into two even with a ultra fast trip breaker (Yes, i have one, i paid good money for that, they trip in 10mS)
600V IS FLOWING THROUGH THE DAMN FUSE!
Okay then, what's the normal procedure of measuring amps? Break up a circuit right? So technically isn't the circuit's FULL voltage flowing through the fuse?
Do you know fuses are safely rated for the voltage before they ARC over even after breaking? Did you know a BS1362 style fuse whether glass or ceramic is 32VDC?
YES. 32VDC. 250VAC. What happens if you have 100amps at 600V flowing through the fuse? BOOM IT GOES and it shatters violently.
What's worse if it doesn't shatter, it will arc over and possibly meltdown your meter and well your hand too if the extremely loud pop doesn't scare you yet
But after that possibly causing a huge fire due to overheated glass from the plasma in the arc
You know why the safety folks are banging on about CAT ratings? This is the REASON. That's why i'm not too sure about anything UNI-T, but i can certainly the both the fuses in the UT61E to HRC fuse and sockets (like monkeh did, props to him) and install MOVs, i'm all set.
If CAT ratings were supposed to be with what? 100A breaking current fuses? If It wasn't neccesary fluke wouldn't bother and all meters will jeopardise somebody's life around the globe every second.
8000V across 2ohms is 40kA and you should know that.
You seem to bang on about not needing HRC fuses, but the truth is, your life depends on it. If you do say "below 50V" What happens if the seemingly not dangerous 32V circuit HAS a potential 500amps flowing through it? BOOM! Glass fuses shatter easily.
The breakover voltage for air might be 1kV/inch but you're wrong if you think the fuse will not arc from end to end, WHEN THEY BREAK they are effectively a few mm apart and that is a recipe for ultimate disaster, that's why you need big or really long fuses
Big fuse = more distance to separate the bondwires and well more sand
Long fuse = They might be held very tight, so if they break they just go off to the other end bu they have less breaking current
MORE CURRENT = FATTER ARC, MORE VOLTAGE = LONGER ARC
Alas, not all BS1362 ceramic fuses are safe. Some of them DO not have sand and thus are not 6kA (or so)
And some glass fuses are probably good for 20amps breaking current MAX
https://www.eevblog.com/forum/product-reviews-photos-and-discussion/beware-the-price-of-some-fluke-fuse-replacement/msg114936/#msg114936