While searching for fuse holders in the web, I found an infinity of pages like this, where the rating of the fuse holder is e.g.:
"10A/250V AC, 15A/125V AC" (it is an example, values do not matter).
I can't figure out what is the meaning these ratings: For the current rating, I can understand that the fuse holder can support at most e.g. 10A, since the contact between the fuse and the fuse holder has a small resistance that generates heat when crossed by big currents. But in this case, this rating should depend only on the current and not on the potential, so why a potential of 125V in the example above allows the larger current 15A?
Moreover, the spec "AC" for the fuse holder is rather strange: what has a fuse holder to do with AC or DC ?
Electronic – spec of a fuse holder
currentfuses
Related Solutions
The "speed", rupture capability, and voltage spec of a fuse are each separate traits that aren't necessarily related. They will be specified according to the nature of the application.
Many cheap multimeters (i.e. <50$us) will only have glass fuses, because they're cheaper. But 'high rupture' capability (the ability to break a circuit up to a rated voltage, when a high fault current is flowing) is important in a multimeter (and in a circuit breaker), especially in a DC scenario, because DC >40V can easily form an arc and continue the current flow, even though the fuse has blown.
For the "20A" fuse in your meter, a HRC type would be wise, and rated for the max V rating of your multimeter, and same speed as the original.
I would do it as with a socketed IC like you are describing.
- Fuse symbol to the schematic with a comment that its socketed.
- BoM for PCBA shows the socket for F7.
- [optional] The actual fuse is in the BoM for top assembly (or some higher subassembly). Plugging in the fuse is a separate operation. It's also possible that slightly different versions of the product may have different fuses.
Best Answer
Fuses first: -
Fuses do need/have a voltage rating - you wouldn't use a fuse that is only qualified for 125V on a 230V AC system. A fuse that is specified for only 125V AC may fail to "break" adequately at 250V AC. These are safety devices after all.
You'll probably also find that some fuses have a "high-rupture-current" rating too. This defines the sudden massive surge of current that may cause a lesser fuse to form a plasma inside the glass/ceramic tube and therefore still conduct and be unsafe.
Fuseholders: -
They have to handle the current and they have to not go unsafe on the voltage that may be placed across them.