Sounds like you have bad short, check your wires for any rubbing or chafing against metal. If the key is not turned on, it most likely would be battery power blowing the fuse.
Google your machine make and model include service manual in the search. you should be able to download a wiring diagram for you machine.
As a precaution disconnect your battery to stop any further damage until you find the cause.
Let me know how you make out.