almost caught fire, electrical help!

i have a 1994 dodge shadow. the other day i was driving and my radio just randomly turned off. after i opened the door i noticed my dome light also didn't work. once i opened the hood i noticed that a 20awg wire coming from the battery was no longer spliced to a 14awg wire that provided power to both my radio and dome light. so i figured problem solved. i cut the wire's and tried to connect the splice just by twisting them together and using electrical tape. well when i tried that the 20awg wire would break as if someone snapped it like a twig. so then i figured just skip the 20awg wire and go with the 14 awg to the large amount of fusible links connected to hot straight from the battery. another bad idea. when i tried i got power to what i wanted to but some other cable( i have no idea what this cable was connected to, all i do know is that it's 20awg, the insulation showing color and tracer was burned off) turned red hot and almost caught fire. what i wanna know is if there's something i'm missing by splicing the 2 cables with a proper 16-14 connector the way it was origionally done or if there's a bad ground or what? i consider myself a pretty competent electrician(though i mostly work with lighting systems), but i'm just confused on this one. any help would be much appreciated. y'know, i want my radio back so i can listen to music, and don't want my car to catch fire at the same time.

you have a short somewhere in the system, and will continue to melt things until you find it and fix it. I definitely wouldn't go to a larger wire...they made the fusible links that size for a good reason....a reason you're discovering!

Finding shorts is never a fun situation, but you at least have some leads, you know its most likely to do with the circuits that involve the dome light and the radio. I'd bet its the radio...

actually, i don't have a short. the problem was that i wasn't propery connecting the fusible link wire to the 14g wire properly. you have to use a butt connecter, you cant just twist them together and use electrical tape. once i spliced it properly it worked just fine. i found out that fuseable link wire is quite different from normal copper wire. it actually works like a fuse where if the impedence of the connection breaks if exceeded. it's like an in-line fuse without the actual fuse. thank you though, i did think i had a short somewhere and spent too much time looking for a short that wasn't actually there. i just needed to not half-ass how i did the electrical and do it correctly.

fusible links are literally smaller than usual wire for a given load. They know how much amperage will kill X rating of wire, and normally build circuits to be very safe for the expected amperage. Fusible links on the other hand, they purposely use wire gauge that is right on the cusp of the likely amperage range of the circuit, so that it will melt and break without damaging the rest of the circuit.

So to reiterate, you have a short, thats why the fusible link melted/crumbled. Trust me on this.