ferrariboy150 wrote:okay so get some 4 gauge.. and there should be two fuses on it? one near the battery, and one near the amp?
Yes, exactly. Somewhere around the TI line, PG quit putting internal fuses in the amps. So, in order to protect the amp itself, you need to externally fuse it.
Okay, 8g is a little better, but still not good enough. 8g is capable of carrying about 50 amps. At this point, with a 60 amp fuse in it, the cable can and will start a fire before the fuse can blow. You would be advised to wait to run it for when you get the larger wire. These are BIG BIG BIG "IFS", but IF you put a 50amp fuse in the wire and get rid of the 60a one, IF you do not run the amp at anything more than low to low mid volumes, and IF you keep the bass boost turned all of the way down and your loudness control on the deck off, and all signal processing flat, THEN you should be relatively safe until you get bigger power and ground wires. If you blow the 50a fuse, turn the subs down, don't put in a larger fuse. If the power or ground wire gets warm at all, turn it down or stop using it.
The reason that you can damage an amp running undersized power wire is simply this: The wire is rated to carry a certain amount of current for it's size because it has resistance. The larger the wire, the lower the resistance. If you try to pull more current than the wire can support, the voltage will drop to maintain the current needed. The voltage drop can be very significant. More than a 5 volts in bad cases. The amp can still run at reduced voltage, however, it will try to draw even more current to make up for it. Increased current causes increased temperature. Eventually the amplifier will destroy itself trying to draw enough current to do it's job properly. That is, if it doesn't melt the power wire and catch the whole vehicle on fire first.
Now, on to wiring it. There should be a fuse or circuit breaker as close to the battery as possible. It should be rated for a little less current than the gauge of wire can support. 4 gauge is typically good for somewhere around 130a. It should be fused at the battery with a fuse value of approximately 125a. This protects the whole length of wire from the fuse back to the amplifiers. If the insulation breaks on the wire, or something cuts it and it shorts to the vehicle, then the fuse will blow and keep you from catching your wheels on fire. It needs to be as close to the battery as possible because the short piece of wire from the battery to the fuse holder will not be protected. This wire should be as short as it can be, and as well routed and protected as possible so it doesn't get pinched, chaffed or broken.
At the amplifier end, the 80a fuse is to protect the amp from similar scenarios to what I outlined above. If something goes wrong internally in the amp, the fuse will blow before it can cause a catastrophic end. If the amp is trying to draw more current because of an inadequate ground, or undersized wire, it will blow the fuse as well. If you roll w/o it, and a channel fails in the amp, the internal damage will be 100x worse than it would be with the fuse.
The ground wire is equally important. It must be the same size or larger than the power wire. What goes in must also go back out.
Another thing you could do to get by for now until you get larger power wire, is this: You could wire your subs in series, giving you an equivalent of an 8 ohm load to the amp. The amp will likely only put out 2-300 watts RMS in this scenario, but I think the power wire would be adequate temporarily.
Later,
Jason