oldschool@tubes.com wrote:> The fuses are 7/8 inch long and are supposed to be SFE 0.5 amp / 250V. >Or better... these: https://www.ebay.com/itm/5pcs-GMA-0-5A-Ceramic-500mA-Fast-Blow-Fuse-0-5-Amp-250v-5x20mm-UsFreeShip/271497805149
Need fuses for Multimeter
Started by ●January 30, 2018
Reply by ●January 30, 20182018-01-30
Reply by ●January 30, 20182018-01-30
On Tuesday, January 30, 2018 at 8:30:35 PM UTC-5, Phil Allison wrote:> olds...@tubes.com wrote: > > ---------------------------------- > > > > > > > >Copied from the internet. > > > > > >This fuse is known by the Garner Bender part of GF-0306 and it is rated > > >at 500mA, 250V fast blow. It is also known as F500mA, 250V. > > >Amazon carries it: www.amazon.com/Littelfuse-500mA-Fast-Blow- > > >Fuse/dp/B000PHCTP2 > > >And Ebay: > > >www.ebay.com/itm/5x-F500mAL250V-F500mA-250V-F500m-L250V-F500mL250V- > > >cartridge-GLASS-fuse-5X20mm-/151136253242 > > >Or do a search on Google for "F500mA 250V fuse". The are easily and > > >readily available. > > > > > >End of copy. > > > > > >That fuse is probably a metric size fuse. > > > > > > > > > > Could you be kind enough to tell me where you found an online "book" for > > this meter? I no longer have the paper version. > > > > http://ec1.images-amazon.com/media/i3d/01/A/man-migrate/MANUAL000034172.pdf > > > ** The fuse is a common, 20 x 5 mm, 0.5A fast blow - it only protects the low milliamp ranges. > > IME, the resistor in the lowest Ohms rage is the most likely to get accidentally blown when using an analog meter. > > Digital multimeters are vastly more rugged than analogues ones, even the simplest 3.5 digit types can tolerate 240VAC on the ohms ranges and are damn near drop proof. > > > .... PhilYes, but there are things you can do with an analog voltmeter that you can't do with a digital one. There is still a usefulness for both. My preference today is a Fluke 179.
Reply by ●January 30, 20182018-01-30
On Tuesday, January 30, 2018 at 3:56:38 PM UTC-5, olds...@tubes.com wrote:> > The fuses are 7/8 inch long and are supposed to be SFE 0.5 amp / 250V.For meters, it's important to use the right fuse. You want one that will definitely OPEN when required to save your life, and stay OPEN afterwards. That usually means a sand-filled ceramic, fast-blow type. RadioShack never had these (to my knowledge). But they are defunct anyway. Try www.digikey.com and save yourself the headache and hassle of searching local retailers for fuses. Even Walmart doesn't carry many of the automotive fuses that you might expect them to. (Ditto for car bulbs too.)
Reply by ●January 30, 20182018-01-30
On Tuesday, January 30, 2018 at 3:56:38 PM UTC-5, olds...@tubes.com wrote:> I have a GB Instruments multimeter (GMT -19A). > I've had this meter for years and it's always worked fine. > > It came with 2 fuses. One was installed in the fuse holder inside by the > batteries. The other is a spare fuse which was in a plastic clip on the > other side of the batteries, and meant to be a spare. > > The fuses are 7/8 inch long and are supposed to be SFE 0.5 amp / 250V. > > I have gone to several hardware stores, an automotive parts store, and a > home improvement center. No one carries this amperage fuse, at least not > in that length (SFE). I thought I'd use a 1 amp if nothing else, but I > cant even find those. > > For now, I found a 9 amp that fits, and am using that, but I know that > is not going to protect the meter. > > I dont buy much online, and only use Ebay when I do. I thought Ebay > surely would have them, but I was wrong. Ebay has SFE fuses, but only in > larger amp sizes. Seems 7.5 amp and higher are common. > > (I searched ebay using these words "sfe 1 amp fuse" ) > > * Now I know why I miss Radio Shack, they usually had stuff like this. > > Does anyone know where I might find these fuses? (Even a 1 amp size). > > No, I am NOT willing to go to one of those places that have a large > minimum order, or charge $10 or more to ship a small item like this. > After all, multimeters like this only cost around $25. > > One thing I did find, is at a local hardware store they do have a few > boxes of AGA 1 amp. Those are a little short though, but I was wondering > about slipping a tiny piece of copper tubing over one end.... > > Without having one of them in front of me, I am not sure what the actual > length is for a AGA type. But a website lists them as 5/8" so I assume > that's correct. I also learned that the AG means "ALL GLASS". > > [ I do wonder if I might still find these using other wording, on ebay. > I really would expect Ebay to have this... ] But what wording???I recently had to replace a DMM fuse. Mine was 5x20mm, which might fit yours. Home Depot has them, 5x20mm, 500mA, 2/$4. Cheers, James Arthur
Reply by ●January 30, 20182018-01-30
In article <23527dl231cg98hlo4578ick8gm18gpie4@4ax.com>, oldschool@tubes.com says...> Your fuse may have a F on it,but probaly not the whole SFE. > > > >Copied from the internet. > > > >This fuse is known by the Garner Bender part of GF-0306 and it is rated > >at 500mA, 250V fast blow. It is also known as F500mA, 250V. > >Amazon carries it: www.amazon.com/Littelfuse-500mA-Fast-Blow- > >Fuse/dp/B000PHCTP2 > >And Ebay: > >www.ebay.com/itm/5x-F500mAL250V-F500mA-250V-F500m-L250V-F500mL250V- > >cartridge-GLASS-fuse-5X20mm-/151136253242 > >Or do a search on Google for "F500mA 250V fuse". The are easily and > >readily available. > > > >End of copy. > > > >That fuse is probably a metric size fuse. > > > > > > Could you be kind enough to tell me where you found an online "book" for > this meter? I no longer have the paper version. > >Look here : http://ec1.images-amazon.com/media/i3d/01/A/man- migrate/MANUAL000034172.pdf The - after man at the end of the line is suspose to be there.
Reply by ●January 31, 20182018-01-31
mpm wrote: ---------- olds...@tubes.com wrote:> > > > > The fuses are 7/8 inch long and are supposed to be SFE 0.5 amp / 250V. > > > For meters, it's important to use the right fuse. >** Use the one the maker specifies. An "SFE 0.5 amp / 250V" is a common, clear glass, single wire strand, fast acting fuse.> You want one that will definitely OPEN when required to save your life, > and stay OPEN afterwards. >** Never rely on a fuse to save you from electrocution.> That usually means a sand-filled ceramic, fast-blow type. >** Such fuses are often specified for situations where fault currents can be VERY large and result in damage to the leads and PCB tracks of a multimeter. The "olds" cheap and cheerful analog meter has an unfused 10 amp range which is a bit of a hazard if he likes poking about with automotive batteries OR 3-phase power. If he prods across a 120 or 230VAC supply, the fuse or breaker in the circuit will blow or trip. If he prods across a 12V auto battery, the leads will smoke and burn and maybe go open circuit. He will then need to get some new leads. However, if he prods across 208/415 VAC, the same leads will explode violently and send hot copper flying about - unless a HRC fuse like you refer to is fitted. Obviously, the GMT-19A meter is not suited or rated for "high energy" circuit use nor is the "olds" himself. .... Phil
Reply by ●January 31, 20182018-01-31
On Tue, 30 Jan 2018 22:38:16 -0500, Ralph Mowery <rmowery28146@earthlink.net> wrote:>> Your fuse may have a F on it,but probaly not the whole SFE. >> > >> >Copied from the internet. >> > >> >This fuse is known by the Garner Bender part of GF-0306 and it is rated >> >at 500mA, 250V fast blow. It is also known as F500mA, 250V. >> >Amazon carries it: www.amazon.com/Littelfuse-500mA-Fast-Blow- >> >Fuse/dp/B000PHCTP2 >> >And Ebay: >> >www.ebay.com/itm/5x-F500mAL250V-F500mA-250V-F500m-L250V-F500mL250V- >> >cartridge-GLASS-fuse-5X20mm-/151136253242 >> >Or do a search on Google for "F500mA 250V fuse". The are easily and >> >readily available. >> > >> >End of copy. >> > >> >That fuse is probably a metric size fuse. >> > >> > >> >> Could you be kind enough to tell me where you found an online "book" for >> this meter? I no longer have the paper version. >> >> > >Look here : > >http://ec1.images-amazon.com/media/i3d/01/A/man- >migrate/MANUAL000034172.pdf > > >The - after man at the end of the line is suspose to be there. >Thanks. It's nice having a manual for it again. I lost a lot of manuals for older stuff, because I had them in a garage and mice decided they were something to chew up. PDF files are better than paper.... The meter does not say the fuse size inside the case, except 0.5 A and 250 V. It's probably a year or more since I needed a fuse and used what I had on hand, which was a SFE 9 A. It fits, but it looks like it did widen the prongs on the fuse holder.I only noticed the wrong size fuse and remembered using the wrong size the other day, when I replaced the batteries in it. One thing I do not understand. In a store I found some other fuses that were about the same size as the SFE. It may have been AGW, but I dont remember for sure. They were 1A fuses rated at 32 volts. They were made out of glass, with the metal ends, just like the fuses rated at 250V. Why would a fuse like that not work at 250 V, or 100 V or any voltage above 32 V? I'm sure the glass container and metal ends would not fall apart. And isn't the element inside just a piece of very thin wire whose gauge is determined by the amperage? So, why wouldn't that fuse work at a (reasonable) voltage over 32 V? (Or up to 250 V)? I'm sure there is a reason, but I sure can not see why? Everything looks identical.
Reply by ●January 31, 20182018-01-31
On Wednesday, January 31, 2018 at 4:01:12 AM UTC-5, olds...@tubes.com wrote: ...> One thing I do not understand. > In a store I found some other fuses that were about the same size as the > SFE. It may have been AGW, but I dont remember for sure. They were 1A > fuses rated at 32 volts. They were made out of glass, with the metal > ends, just like the fuses rated at 250V. > > Why would a fuse like that not work at 250 V, or 100 V or any voltage > above 32 V?The glass fuse can explode. Also, with an automotive rating of only 32 volts, there is no guarantee that once the fuse blows, the resulting molten metal (deposited who knows where within the glass envelope, assuming it did not burst) may not separate enough to eliminate a continuous arc of current. It is also possible (with enough molten material) to re-form a conductive path afterwards. Either situation: Not good. Lesson: There's more to fuses than meets the eye. Always use the right fuse for the application! And as Phil mentioned, don't rely on a fuse to safe you from electrocution. They help, but your brain and common sense helps a lot more. (As do engineering safeguards, such as shipping products with the correct fuses in the first place, and specifying the replacement fuse prominently on the device.)
Reply by ●January 31, 20182018-01-31
olds...@tubes.com wrote: -------------------------> > One thing I do not understand. > In a store I found some other fuses that were about the same size as the > SFE. It may have been AGW, but I dont remember for sure. They were 1A > fuses rated at 32 volts. They were made out of glass, with the metal > ends, just like the fuses rated at 250V. > > Why would a fuse like that not work at 250 V, or 100 V or any voltage > above 32 V? I'm sure the glass container and metal ends would not fall > apart. And isn't the element inside just a piece of very thin wire whose > gauge is determined by the amperage? So, why wouldn't that fuse work at > a (reasonable) voltage over 32 V? (Or up to 250 V)? > > I'm sure there is a reason, but I sure can not see why? Everything looks > identical. > >** In normal use, a fuse has a low voltage across it until the conductor inside heats enough to melt and break the circuit. What happens in the next few microseconds depends if the load is *inductive* or not and if the supply is *AC or DC* and how many amps the supply can deliver into a short circuit. A fuse that is marked 32V is suitable for use in 12V & 24V DC automotive circuits. Means it can handle inductive loads ( solenoids and motors) at the moment of breaking PLUS break DC current in the hundreds of amps without arcing end to end. A fuse marked 100V, 120V or 250V is suitable for domestic AC appliances but not as an automotive fuse. Many such fuses are only rated to break 10 times their marked current value and rely on installed supply fuses / breakers to open in short circuit situations. ..... Phil
Reply by ●January 31, 20182018-01-31
On Wednesday, 31 January 2018 09:01:12 UTC, olds...@tubes.com wrote:> One thing I do not understand. > In a store I found some other fuses that were about the same size as the > SFE. It may have been AGW, but I dont remember for sure. They were 1A > fuses rated at 32 volts. They were made out of glass, with the metal > ends, just like the fuses rated at 250V. > > Why would a fuse like that not work at 250 V, or 100 V or any voltage > above 32 V? I'm sure the glass container and metal ends would not fall > apart. And isn't the element inside just a piece of very thin wire whose > gauge is determined by the amperage? So, why wouldn't that fuse work at > a (reasonable) voltage over 32 V? (Or up to 250 V)? > > I'm sure there is a reason, but I sure can not see why? Everything looks > identical.A 32v fuse on 240v is likely to arc over on breaking, then surrounding materials feed the arc to keep it conducting. You get a fireball instead of a break. NT
