What causes a fuse to blow?

Last night I had to replace the fuse in my bucking transformer. My VTA ST70, PH14, SP14 and my tube buffer are all plugged into a power strip which is plugged into the bucking trans. which is plugged into a manual reset GFCI.

The system was working fine the night before and nothing had been touched or moved. I just turned on the system last night and no power.

After checking everything else out, I got to the fuse in the bucker and it was obviously fried. I replaced it and all seems to be fine now.

I'm not a tech so I'm just curious whether this could just be a fluke fuse failure or something to worry about?

Thanks in advance for your opinions.

Fuses are actually wearing parts, and age out over time. You have not given us any details on loads as compared to fuse ratings, but if they are close, the aging process will be even faster. Also, could be a spike or surge.  If it happens again, check everything with an ammeter.

Thanks. The fuse is a 4 amp 250 volt as recommended by the guy who designed my bucker. When I first set it up I asked here if it was stout enough for the VTA pieces and was assured it was all good. BUT....I have upgraded to a separate phono pre-amp since then. (SP/PH 10 to an SP 14 and Ph 14 and the Yaqin buffer).
Anyway, it's been working fine for about a year with the new gear so I guess it was just a worn out fuse.

Dave_in_Va wrote:Last night I had to replace the fuse in my bucking transformer. My VTA ST70, PH14, SP14 and my tube buffer are all plugged into a power strip which is plugged into the bucking trans. which is plugged into a manual reset GFCI.

The system was working fine the night before and nothing had been touched or moved. I just turned on the system last night and no power.

After checking everything else out, I got to the fuse in the bucker and it was obviously fried. I replaced it and all seems to be fine now.

I'm not a tech so I'm just curious whether this could just be a fluke fuse failure or something to worry about?

Thanks in advance for your opinions.

As all connected devices will turn on at THE SAME MOMENT a high peak current will occur.
Larger set's of computers are sequenced to turn on, not at the same moment but gradually.

Installing delays will reduce peak current providing it's not the same delay in all devices.

Thanks.
I don't turn on everything at once......PH 14, then the SP 14 and then the ST 70.

Forgot to switch it from BLOW to SUCK?

Not to forget, they work both ways. Maybe you took a surge through the wall. Storms or switching problems at the power company ...

DO resist the urge to put a larger or slow blow fuse in ...

I mentioned this on another thread, but a blown fuse can continue to conduct if it flashes just right. Prolly worth checking every once in awhile. Fluke puts two fuses in their meters for just that reason.

THAT, for the record, is why one does not purchase or use fuses from dubious sources. Littlefuse, Bussman, Gould - you get the picture.

Peter W. wrote:THAT, for the  record, is why one does not purchase or use fuses from dubious sources. Littlefuse, Bussman, Gould - you get the picture.

Peter, are those good guys or bad guys?

Those are the Good Guys.

Thanks, Peter,
I'm going to be re-tubing next week and there's always a lame duck in the bunch, esp. with NOS, so it's always nice to have a stash of fuses in hand.

Dave, is all well with that fuse problem?? If you suggest I can bring my Fluke clamp-on and we can do a load test next week.

Dale

Dale Stevens wrote:Dave, is all well with that fuse problem??  If you suggest I can bring my Fluke clamp-on and we can do a load test next week.

Dale

Good idea! And though all of this, I neglected to ask what kind of 4A fuse is being used. I am of the personal belief that slow-blow (NOT actual time-delay) fuses are the invention of the devil designed to protect real-estate, somewhat and destroy equipment regularly.

DUAL-ELEMENT fuses are the way to go. They act as fast fuses after the initial surge, and may be tailored closely to the load.

I keep a metered variac for this purpose - very accurate, very useful.

http://www.byan-roper.org/steve/_Media/img_0306-2.jpeg  Not mine, but the same model.

The new fuse is working fine.