Good evening folks - thoughts/advice please
… is there a British Standard for these types of fuses ?
… how would using them in circuit sit regarding BS7671 ?
Regards
Habs
Good evening folks - thoughts/advice please
… is there a British Standard for these types of fuses ?
… how would using them in circuit sit regarding BS7671 ?
Regards
Habs
In days past such thing were used a lot inside TV sets and similar, and the glass bodied ones had a disappointing failure mode, where the end caps stayed in the holder, and the glass had to be swept out of the set with a dustpan and brush. Nowadays the glass bodied ones sometimes pop up inside things like laptop power supplied, and are one step up on the PCB weak link, but there is no expectation that they will be changed once blown, as the unit is sealed, and being sealed, the glass can be allowed to explode, and the unit remains safe. It does not sound nice but it is an acceptable design to allow the outer casing to catch the bits.
The other things to watch with really low values are failure on in-rush - they are a lot friskier than say 13A plug style fuses, especially the ‘F’ (flink = fast,nimble) type let through is reassuringly low, and the significant element resistance, less of an issue on 230V..
Do not try to fuse your load too closely unless you use the ‘T’ (träge = slow, sluggish, lazy) type. Thanks DIN.
more generally
| DIN Marking | Description |
| FF | Very Fast Acting Fuse (Flink Flink) |
| F | Fast Acting Fuse (Flink) |
| M | Medium Acting Fuse (Mitteltrage) |
| T | Slow Acting Fuse (Trage) |
| TT | Very Slow Acting Fuse (Trage Trage) |
 | Slow Acting Fuse |
In days past such thing were used a lot inside TV sets and similar, and the glass bodied ones had a disappointing failure mode, where the end caps stayed in the holder, and the glass had to be swept out of the set with a dustpan and brush. Nowadays the glass bodied ones sometimes pop up inside things like laptop power supplied, and are one step up on the PCB weak link, but there is no expectation that they will be changed once blown, as the unit is sealed, and being sealed, the glass can be allowed to explode, and the unit remains safe. It does not sound nice but it is an acceptable design to allow the outer casing to catch the bits.
The other things to watch with really low values are failure on in-rush - they are a lot friskier than say 13A plug style fuses, especially the ‘F’ (flink = fast,nimble) type let through is reassuringly low, and the significant element resistance, less of an issue on 230V..
Do not try to fuse your load too closely unless you use the ‘T’ (träge = slow, sluggish, lazy) type. Thanks DIN.
more generally
| DIN Marking | Description |
| FF | Very Fast Acting Fuse (Flink Flink) |
| F | Fast Acting Fuse (Flink) |
| M | Medium Acting Fuse (Mitteltrage) |
| T | Slow Acting Fuse (Trage) |
| TT | Very Slow Acting Fuse (Trage Trage) |
| Slow Acting Fuse |