Hey all, I know I haven't been on here for ages. Truth is I did some time and I had to sell EVERYTHING! I'm not happy but anyway, I have a problem. My check charging system light came on and so I looked under my hood and I found this:
I am wondering what may have caused this, the fuse seems to not be blown and there doesn't seem to be any other problems in the wiring or anything else.
looks like it shorted to bare chassis metal and the heat melted the structure. Sometimes the cable feels stiff, but when it's subjected to engine heat, it can soften up and become pliable, and move around, or droop and come into contact with things. I've seen that happen a lot of wiring going to the alternator or chassis ground points under the hood. People route wire and think it looks good but they leave slack in it, so when it heats up and gets soft, it's not secured to anything, and droops down onto the intake, exhaust manifold, etc, the insulation melts, you get a short, and a blown fuse and/or chunk of melted goop and a small fire.
The more I look at this, I see just the plastic housing over the connection point melted, which can also be a result of a poor connection causing heat build up from high current draw through too-small wire (or a bad connection point having the same effect) It could also have happened from extreme engine compartment heat if that fuse was close to a heat source.
I had this happen i was running 4 gauge wiring with 1200rms and the wire would melt by the fuse every month or so i would have to cut it and reinsert it.. Changed it to 0 gauge wire and haven't had the problem since...
Julian, that would be an example of a bottle neck in current flow causing a build-up of heat at the weakest point in the circuit (where the wire joins the fuse holder, and is connected together with an allen screw, typically) and one reason I really have a strong preference for soldered connections when dealing with high current connections.
On a side note, when you're using 0 gauge wire, you will typically need an upgraded electrical system to supply that much current (bigger alternator) for others thinking about this sort of an upgrade. The amp may be able to produce 1200 watts (120A of current draw) or more, and the wire may be rated to handle it (250+A for 0 gauge) but if the alternator is only rated at 90A for example, that's all you'll be able to feed anything, and the car itself requires a good portion of that current for other things.
