Odd value 20mm 700v 250mA Ceramic fuse finding

[OwenM]

Hi there

I have a super cheap DMM that I can use and abuse without worry and the mA scale fuse has gone. I have no idea why, I don't think I've ever even used that before on this particular meter. Anyway, its a 700v 250mA ceramic in the 20mm package and I can't find them ANYWHERE. I can find that rating but only in the larger 32mm and 38mm packages. Anyone know anywhere I may be able to get one from?

I suppose I'm unlikely to be measuring current near 600v with this meter anytime soon, but would rather the correct fuse of course. I could probably just use the 10A current mode on my meter as thats normally close enough for what I need, but anyway, if anyone knows off hand a source for this odd size/rating then that would be cool!

EDIT - doing two things at once, its 250mA but I still can't find one!

[Enzo]

A quick trip to Mouser and in 20mm size fuses at 250ma (0.25A) I find 8 choices in ceramic, and 39 choices in glass.

I don't know your favorite (favourite?) supplier in teh UK, but 250ma 20mm fuse should not be a rare item.

Check the big parts houses, and start with "fuse 20mm" and use the search parameters to narrow it down from there.

[OwenM]

A quick trip to Mouser and in 20mm size fuses at 250ma (0.25A) I find 8 choices in ceramic, and 39 choices in glass.

I don't know your favorite (favourite?) supplier in teh UK, but 250ma 20mm fuse should not be a rare item.

Check the big parts houses, and start with "fuse 20mm" and use the search parameters to narrow it down from there.

Thanks for the reply! I think the tricky aspect is the 700v rating, I've tried looking for 1000v rating too thinking that may be a bit more common, but once you narrow down a search to 250mA 20mm ceramic fuse on the uk mouser the highest voltage they offer as a filter-option is 250v... The highest voltage rating they offer for any ampage of 20mm fuses full stop is 600v ac and 500 dc...

Hehe, I appreciate the extra 'u' for me across the pond

[The Dude]

Frankly, I'd have no problem using a 250V fuse in that application- same as many other meters use.

[g1]

What is make and model of meter?
It's possible the fuse has a fake rating.

[Leo_Gnardo]

Frankly, I'd have no problem using a 250V fuse in that application- same as many other meters use.

Same here, and I wouldn't worry about the ceramic body either. They may have chosen that with a nod to safety. Who wants to shake tiny shards of glass out of your mini DVM? I'm sure a standard glass body fuse would work just fine.

[J M Fahey]

Inside a *cheap* DMM?

Then those must be 700V PMPO

I would use a 250V standard fuse there.

[OwenM]

Thanks guys, 250v it is then!

g1 it's a Tacklife dm08!

[Jazz P Bass]

Not too sure if this is a misprint in the manual.
100V max???

[OwenM]

Not too sure if this is a misprint in the manual.
100V max???

Yeah, the whole thing is somewhat 'non pro', the manual seems to have been knocked together in an evening... A few pages on it says max voltage 600v but I'm still bloody cautious when using this thing!

[vintagekiki]

I would use a 250V standard fuse there.

Just so
Overload protection: Standard Fast blows Fuse (5 x 20 mm)
uA/mA Range: F250mA
10A Range: F10A

https://manuall.co.uk/tacklife-dm08-multimeter/

[g1]

"NCV/OVERLOAD PROTECTION:When the detected voltage is greater than 90V (RMS), the flashlight will flash and the buzzer alarm,when a short-circuit accident accur, the double explosion-proof ceramic fuses will quickly blow, which will greatly reduce the risk of safety"

I can't find 'double explosion-proof' in the fuse selectors at any of the electronics suppliers. Must be double-secret.

[vintagekiki]

I can't find 'double explosion-proof' in the fuse selectors at any of the electronics suppliers. Must be double-secret.

About 'double explosion-proof'
Safe Ceramic fuse inside are filled with fine quartz sand, which extinguishes the spark that can be formed by burning the calibrated fuse wire.

[Helmholtz]

Fuses are not only rated for current (performance) and voltage (safety) but also for breaking current capacity (safety) , where required.
https://en.wikipedia.org/wiki/Breaking_capacity

[OwenM]

"NCV/OVERLOAD PROTECTION:When the detected voltage is greater than 90V (RMS), the flashlight will flash and the buzzer alarm,when a short-circuit accident accur, the double explosion-proof ceramic fuses will quickly blow, which will greatly reduce the risk of safety"

I can't find 'double explosion-proof' in the fuse selectors at any of the electronics suppliers. Must be double-secret.

I also like 'reduce the risk of safety' ie. reduce the risk of being safe. Additionally I only use double explosion proof equipment across my whole household, finding a double explosion proof whisk was a bit of a headache but nice to know I am half as likely to suffer severe explosion in my day to day business.

In other news, I put in the new fuse and it blew as soon as I tried to use the mA testing range, 2 more down and I see why the fuse was blown even though I don't recall using that feature on the DMM since I bought it! The 10A range is showing me the device I'm testing is running at about 2mA of current so I think theres a junk pile around here somewhere that this thing will be finding a home in in the not too distant future. Took the opportunity to order a fluke and my other midrange DMM will now serve as the backup once this one is kicked out the back door!