I’m planning on building a fuse into my midibox, I like to be sure 
Does anybody have an idea at what kind of current the fuse should snap?
aa weell I put a 1A… just in case of some thing go really wrong..
to calculate good value :
mesure the current flow under 5V, and if you have 220V input (like in europe), then muliply the current by 5/220… I think I’m right, but not sure! 
Wont the rectifier be fried long before 1A is reached?
yes… 1A under 220 makes about 44A under 5V 
but if there’s a short circuit… ;D
ghehe LOL.
You’re right, when I have all my module I will put a 250mA fuse on the 220 sector! it will be safer!!
I think i’m going to use something like a 2,5A fuse in the 5v area.
huumm yes, but don’t forget to put a fuse for the 220… it’s a protection, if there’s a short after the transformer!!!
I will be using a wall-adapter, so i cant modify that
I always check the current like that: I dont switch on (the fuse holder is right behind the switch and shortened) and measure the current between the both pins of the switch (so the MB comes on).
Then I just put all LEDs on, the luminence of the LCD to the max and so on and take the current as a basic number. Meaning: If I read like 200-300 mA I use a 500 mA Fuse, if I read 500-800 then 1A and so on.
I always put the fuse behind the wall-adapter, as the most adapters already have short-protection inside.
Hope that helps somehow.
oh yes it help! I must be stupid, but mesuring the current on the switch is a great idea!.. (I make diy stuff for about 4years now.. ;D.. then I must be stupid!)
Erm, imho we have 230 and not 220 Volts, right? Just for the calculations…
Fuses are cool. 8)