Running the right gauge wire is vital if you want to get reliable power to your amp. Seems simple, right?
Here’s the trick: avoiding excessive heat (and yes, wires can get hot) and voltage drop is the enemy. The best way to do that is to run half of the wires max power rating. To figure that out:
- Look at the length of the wire run. Remember to account for the entire circuit. That means the full distance that power and ground wires travel.
- Once you know that, check with the manufacturer to determine the maximum amperage the wire can handle. Let’s say you have a 20’ run, including both power and ground wire.
- Now, look at the recommended fuse size for each of your amps. Add them up. Let’s say for example that your total is 300 amps.
- If a 1/0 AWG wire can carry a maximum of 300 amps of draw 20 feet, then you would need 2 runs to appropriately carry that amount of current.
If you have a battery up front wired into your system, you have to account for an additional 60-70 amps worth of current draw for the vehicle’s day-to-day operation. It’s important to note that this is always true – whether you have CCA or OFC wire, Lithium or AGM batteries. Many people running 4 AWG power wire have issues powering their amps for this very reason. If you do the math, that’s often about half of the power an average 4 AWG power wire can take, which means you have virtually no room left to account for your amp’s power demands.
The last part to account for is the quality of the ground. Your best option is almost always going to be the alternator case. This means the foot or ground stud if available. Most motor mounts are unreliable as a ground, as are the panels of the car (especially unibody) since adhesives are often used instead of welds. Poor conductivity equals heat, and system noise. You want neither.
There are those who get the cheapest wire, as if it’s an afterthought – a simple check box to tick off after you’ve spent your real budget on speakers amps, etc… To those people, I’d ask you to picture this: say you buy a sports car. It handles like it belongs in F1. It accelerates so hard you’d swear it has a jet engine. Would you fuel it with the cheapest gas you could find? No. Never. Wires are the same way.
Running the right gauge and quantity of wire through your system can make all the difference. Your amplifiers stay at their proper operating temperature, you don’t add line noise to the system, and you get the power you need, when you need it.