wire size FYI

[Steven 10+ year member]

I know there is a big deal about wire sizes in car audio.

For systems over 200W modt people recommend a wire size of at least 6AWG.

My system puts out over 1500 watts and at times draws over 100amps from my battery, and I am using 10gauge wire. The voltage at my amps always reads the same as at my battery and the wire itself never even begins to heat up (at least not enough to feel through the insulation). technically if the hype about wire were as dire as people make it sound my car would've burnt to the ground months ago.

Now don't get me wrong, I still believe that the larger the wire the better, but running 00 gauge wire for a 1000Watt system is ridiculous. And obviously if you run 14G for a big system yes the wire will heat up and burn.

When it comes to wiring in a vehicle a good rule of thumb is to go with one size bigger than you need. If you need 10G, then buy 8G.

People have told me that if you use too small of wire then the resistance of the wire will cause a "severe" voltage drop. but what is a "severe" voltage drop. I've had people say that more than 2 volts is unacceptable while others say that more than 0.5 volts is reason enough to go up one size in wire. Well if voltage drop is so bad, then what happens when that big bass note comes along - the voltage in my car (with engine running) sometimes drops below 8 volts (measured both at the battery and at the amps). Thats over a 6volt drop - better increase my wire size to 000. B.S.

What do you guys recommend for wire sizes for different wattage systems?

e.g. 200watts, 500watts, 1000watts, 1500watts, 2000watts.

I would like to put together a car audio page but would like to learn somethings from the experts. ie. you guys

Car Audio is a very diverse world and everyone has different Ideas for what is good, bad, required, optional, etc.

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[Alaxan 5,000+ posts]

Now have you had that voltage meter held on there during the amp running hard? Not saying it is pointless, but it is important to use a proper gauge of wirirng for the amount of draw. I am running 4 high current amps right now and have a 0/1AWG wire comming into my D-block. It is important not to tell a new person to caraudio whom is asking questions about wire size too large or small and I do agree here, but there are degrees of overkill that some people want to spend the extra money on.

 

[Steven 10+ year member]

I'm not saying that wire size isn't important. It's just not anywhere near as serious as most people make it sound. More important things are:

#1. The install itself

#2. The ground connection

#3. keeping the Power and signal wires separate

#4. Your listening "attitude"

 

[chris229 10+ year member]

Originally posted by Steven I'm not saying that wire size isn't important. It's just not anywhere near as serious as most people make it sound. More important things are:

guess you could say i'm a guy who takes wire size very serious-------- cause at 100A with 10 gauge power wire that is a 2.03v drop. Plus resistance = heat

#1. The install itself

why worry about the install when you don't know how to supply power?

#2. The ground connection

why worry about the ground?? just ground the system to the car with the same gauge wire as the power wire

#3. keeping the Power and signal wires separate

trust me that is the last thing you need to worry about ----------- cause it's B.S

#4. Your listening "attitude"

true

 

[Steven 10+ year member]

I don't think you read my entire post.

Even during heavy pounding the voltage at the amps and at the battery remained the same. So there is NO voltage drop in the wire.

And why is running signal and power wires together not a bad idea. Most of us don't have fiber optic cables to transmit the signal to our amps, so we have to worry about inducted noise.

 

[chris229 10+ year member]

Originally posted by Steven I don't think you read my entire post.

Even during heavy pounding the voltage at the amps and at the battery remained the same. So there is NO voltage drop in the wire.

let me just jump in and say------------------ IMPOSSIBLE the laws of physic prevent it----------- unless you have invented the first room temp SUPERCONDUCTOR Beleive me you losing 2v @ 100A the math is simple

And why is running signal and power wires together not a bad idea. Most of us don't have fiber optic cables to transmit the signal to our amps, so we have to worry about inducted noise

I don't have optical signal cables either---- yea you do have to worry about inducted noise but not from the power wire. Think about this---- The best time for noise to get in the signal and be loud is when the signal is at its least---- S/N ratio this is the same time when the current in the power wire is at its least too. The amount of current is tied to the amount of signal going to the amp--------- so now do you see why?

 

[maylar 10+ year member]

Originally posted by Steven People have told me that if you use too small of wire then the resistance of the wire will cause a "severe" voltage drop. but what is a "severe" voltage drop. I've had people say that more than 2 volts is unacceptable while others say that more than 0.5 volts is reason enough to go up one size in wire. Well if voltage drop is so bad, then what happens when that big bass note comes along - the voltage in my car (with engine running) sometimes drops below 8 volts (measured both at the battery and at the amps). Thats over a 6volt drop - better increase my wire size to 000. B.S.

How much voltage drop is acceptable depends on the design of your equipment and the performance you want from it. Maybe you can tolerate distortion due to your amps going non-linear during peaks. Or if your amps have regulated power supplies, they might hold their output even when the input drops (within limits). But some amps will become unstable and oscillate if the power line impedance is too high. Most amps' output power is directly proportional to the input voltage. Maybe you don't care if you lose some. Most people do.
Wire gage has 2 aspects: safety and voltage drop. Safety is the wire heating up beyond 40 degrees above ambient (NEC codes). That is affected only by wire gage and the ~average~ current. The wire gages recommended for car audio are way overkill if you're looking at safety only.

But music has about a 5:1 peak-to-average ratio, and those peaks are important if you want a system that thumps and remains clean at high levels. That's where voltage drop becomes important.

BTW if your battery voltage is going to 8 volts, your alternator isn't long for this world.

 

[mattj 5,000+ posts]

Just go buy some OFC 1700+ strand 4 awg wiring and youll be fine.

 

[Steven 10+ year member]

OK. I got myself A more sensative voltmeter. YES there is voltage drop along the power wire. less than 0.01 volts, not exactly a problem

 

[Steven 10+ year member]

Also CHRIS229.

Even the amps idle current can induct a noise into the signal wires. most amps have an idle current between 500mA and 5A, that could induct a significant amount of noise into a system thats recieving 2-4volts of input

 

[rco8786 10+ year member]

Originally posted by chris229 trust me that is the last thing you need to worry about ----------- cause it's B.S true

Go run your power wire next to your RCAs

 

[rco8786 10+ year member]

Originally posted by chris229 let me just jump in and say------------------ IMPOSSIBLE the laws of physic prevent it----------- unless you have invented the first room temp SUPERCONDUCTOR Beleive me you losing 2v @ 100A the math is simple I don't have optical signal cables either---- yea you do have to worry about inducted noise but not from the power wire. Think about this---- The best time for noise to get in the signal and be loud is when the signal is at its least---- S/N ratio

this is the same time when the current in the power wire is at its least too. The amount of current is tied to the amount of signal going to the amp--------- so now do you see why?

Just to be annoying, but the laws of physics also prevent bumblebees from flying...

 

[Alaxan 5,000+ posts]

Originally posted by rco8786 Just to be annoying, but the laws of physics also prevent bumblebees from flying...

The laws of physics also disprove evolution, but it is still passed on as fact.

 

[maylar 10+ year member]

Originally posted by Steven Also CHRIS229.

 

Even the amps idle current can induct a noise into the signal wires. most amps have an idle current between 500mA and 5A, that could induct a significant amount of noise into a system thats recieving 2-4volts of input

********. You obviously have no idea what induced noise is and how it happens.

 

[chris229 10+ year member]

Originally posted by Steven OK. I got myself A more sensative voltmeter. YES there is voltage drop along the power wire. less than 0.01 volts, not exactly a problem

you did do the test correctly------------------------ there must be 100A flowing in the wire first