Instructables

Holder for a Glass Fuse

Picture of Holder for a Glass Fuse
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This is a free multimeter I got at Harbor Freight with a coupon. It came as a surprise, but there is a fuse inside.

See the second photo. Details about the fuse are included on the back of the meter's case, but it is easy to miss them. See the yellow arrow. The fuse is 0.5A at 250 volts. The size is 5mm x 20mm.

See the third photo. This is the fuse in the factory supplied holders.

See the fourth photo. The factory fuse holders are more flimsy than any I have ever before seen. When the fuse is removed, the holders move. The holder on the right feels especially loose and marginal. If they were made of heavier material, I would simply resolder them. But, I want to replace them. (I could just solder the fuse to leads, but I want replacement of a blown fuse not to require a soldering iron.)
 
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Step 1: First steps

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Cut two sections of brass tube the length of the end caps on the glass fuse.

See the second photo. Ream away rough edges and clean the inside of the brass tube with a round file.

Tools
  • Tubing cutter
  • Round file
  • Soldering iron and solder
  • Small scissors
  • Pair of pliers
  • Heat source (hair dryer, match, etc.)
Materials
  • 9/32 O.D. brass tubing
  • Heat shrink tubing

Step 2: Fitting the tubing

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I found I needed to remove nearly one-fourth of the circumference of the brass tubing so it could fit snugly around the end cap on the glass fuse. I used a small stainless steel scissors.

See the second photo. I used a pair of pliers to make the tubing fit the fuse. It was still a little loose, so I crimped the tubing just a little without the fuse to get a closer fit. Caution: These little glass fuses are delicate. I broke one by pushing too hard on it.
tutdude9810 months ago
Nice instructable Phil
What if i use slow instead of fast fuse? fast fuse will blow just when i put 260 ma on 250 ma fuse i need to replace them and if i will use slow fuse i can put maybe 300 ma before it will actually blow
Phil B (author)  tutdude9810 months ago
Thank you for looking and commenting. I think I am not really qualified to give you a reliable answer. I do not know what parameters the circuit's designer had to consider in his selection of a slow blow versus a fast blow fuse, or vice-versa. I suppose you could try it and hope the device passes the "smoke test."
arkangel197510 months ago
Oh wow I think I paid too much for mine... about .99 cents.... LOL

On the up side pretty good for a buck except its margin of error seems to vary 1-4.5 "points" depending on the settings (as compared to my 4 year old fluke)
Phil B (author)  arkangel197510 months ago
Well, do not feel to bad. I paid $15 for one that looks exactly like this one, except that one has fewer features and is black. But, I needed it in that place at that time. It would be hard to beat a Fluke.
explosivemaker10 months ago
Finally had to get a 9V charger since mine kept running out of power...the irony.
bobzjr10 months ago
Phil, Even as bad as I am with solder, I think I could pull this one off. Thanks for sharing. I have that meter too - somewhere in my garage.
Phil B (author)  bobzjr10 months ago
Bob,

I used a little 15 Watt pencil point soldering iron for attaching the leads to the circuit board. That helped a lot. If I had not disturbed the fuse all would likely be well for all time. I would like to try a fuseholder with the thin brass sheet I mentioned sometime.

Thanks.
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