Need help finding unusual multimeter fuse

E

ErichS

New member
Got this multimeter from circuitspecialists.com a while back but they don't sell them anymore.

http://www.p-mastech.com/products/04_dm/ms8218.html

Blew the current tester fuse last night. The replacement fuse spec is 630ua, 500V ceramic cartridge. I can't find this anywhere in the US (I found them on a UK website but shipping is ~$18!).

I've found 250v versions in the US but I don't know if that would be sufficient - I suppose they used 500v for a reason. I also found a 600v version, but usually you don't want to use an over-spec fuse.

Anybody know if either the 250v or 600v would be suitable in this application, or where I might find a 500v fuse like this?

Thanks
Erich
 
ErichS said:
I suppose they used 500v for a reason. I also found a 600v version, but usually you don't want to use an over-spec fuse.
Erich
Click to expand...

the reason they use a high voltage here is simply that some people do high voltage work... typical B+ voltages in tube amps can run 500V easily... the spec you dont want to over do is not voltage here but rather current... think of it as voltage is the pressure in a hose... current is the shear volume of water... make sense??? check mouser and or digikey...
 
Thanks for the replies M1Fanatic and Dementedchord.

The fuse size is 6x30mm. (630ma, not ua as I originally posted)

I had previously checked Mouser, Digikey, and Newark (and numerous other places) and they only stock the 250V version. Although Mouser and Digikey both list a 400v version as a non-stock item.

dementedchord said:
the reason they use a high voltage here is simply that some people do high voltage work... typical B+ voltages in tube amps can run 500V easily... the spec you dont want to over do is not voltage here but rather current... think of it as voltage is the pressure in a hose... current is the shear volume of water... make sense??? check mouser and or digikey...
Click to expand...

So using a 600v version does not risk damage to the meter if I were to measure current in a high voltage circuit? I do use this meter to check B+ and for setting Bias current on my tube amps, one of which is a 79 twin with B+ ~470v!
 
M1Fanatic said:
I'd use this one if I couldn't find the original.

http://www.testpath.com/Items/Fuse-630mA-600V-6x32mm-Ceramic-Pkg-of-4-122-085.htm

You probably already looked at this one. As was mentioned, it's the current you need worry about.
Click to expand...

M1, I really appreciate you looking around for me. Yep, that was the 600v one I referenced.

Dementedchord, it's actually $18 for a pack of 4, so it's a steel right?:D

There is also a 500mA, 600v version on that site for only 7$ for 4 but I guess I loose 130mA headroom - don't really know if that is an issue either.

Thanks again for the replies
 
ErichS said:
Got this multimeter from circuitspecialists.com a while back but they don't sell them anymore.

http://www.p-mastech.com/products/04_dm/ms8218.html

Blew the current tester fuse last night. The replacement fuse spec is 630ua, 500V ceramic cartridge. I can't find this anywhere in the US (I found them on a UK website but shipping is ~$18!).

I've found 250v versions in the US but I don't know if that would be sufficient - I suppose they used 500v for a reason. I also found a 600v version, but usually you don't want to use an over-spec fuse.

Anybody know if either the 250v or 600v would be suitable in this application, or where I might find a 500v fuse like this?

Thanks
Erich
Click to expand...

You mean to tell me those guys at MASTECH TECH SUPPORT won,t send you a fuse for a multimeter you purchased recently? You cn,t get one from them directly?
 
The votage rating is for flashover. In other words, if a fuse rated at 250V pops while measuring a 500V circuit, there could be additional arcing for a few microseconds while more of the fusible material burns away. I've used 250V fuses in similar circumstance many times, and you'll definitely be good to go with the 600V rated one.

EDIT: Is this it?
 
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