Since I find myself wiring up a new case I find myself wondering - is there a good guide to fuses out there?
Suggestions for appropriate values and placement and whatnot?
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I have a 2A glass fuse between the 230V connector and the power switch. On my new psu, I have put 2 4A polyfuses right behind the 12VAC connectors.
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As @TimMJN implies there are two places for fuses, between the wall and the PSU, and between the PSU and the modules.
For the former, if you have a wall wart supply I’d say they’re not required. Otherwise, if your PSU transformer is supplying, let’s say, 1 A of current at 12 VAC and your wall voltage is 120 VAC then it should be drawing 100 mA of current — 1 A times 12 VAC / 120 VAC. But if something’s gone wrong, a short or whatever, the current will presumably be much higher, several amps. The fuse needs to be in that range.
But that’s steady state. When you first turn it on it’ll draw more. So… On my new case PSU I’ve used a 1 A slow blow glass fuse. 1 A to be well above ~100 mA (it may be more by the time case fills up) but below what a short would produce, and slow blow to accommodate the startup surge.
On the outputs of my wall wart PSUs I’ve used 1.1 A polyswitch fuses. I don’t have any on the new PSU, but it has overcurrent protection at 120% of rated power.
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