Ceramic Fuse Black Line

A ceramic fuse however shows no damage upon visual inspection.

Ceramic fuse black line.

A homeowner can determine if a glass fuse in blown by performing a visual inspection and looking for a break in the thin wire and a brown discoloration in the center of the fuse. The presence of a ceramic fuse ensures that an electrical surge is unable to harm the inner components of the microwave. It s easy to tell if a glass fuse is blown. To check a ceramic fuse use an ohmmeter or continuity tester.

Blade fuses are sometimes physically difficult to pull out but most vehicles come with a fuse puller tool that is located inside one of the fuse boxes or attached to a fuse box lid. It worked fine until i open the microwave door it blows every fuse i put in it. Testing a ceramic fuse is the only way to tell if the fuse has blown. So i took it apart and saw that the fuse had a black line going around the fuse.

So i bought fuses and replaced the old one. Unlike glass fuses those ceramic fuses called current limiting fuses are very fast acting filled with sand that melts into glass shall a fault occur which is an insulator thus opening the electrical circuit. Product title 14qbp20csb microwave ceramic slow blow fuse 20 amp. What does this mean.

Are they just made like that. It will show scorch marks and the filament will be melted. It may be a glass fuse with a filament or a ceramic fuse.