What are some basic guidelines for the size power wire you need to supply amps? IE

X guage = 200 Watts
X guage = 300 Watts
And so on...

Also what about inline fuses?

I have a 300 watt amp that says use 10 guage wire and a 30 amp inline fuse.
I've also got another 250 watt amp, that I don't know much about the specs, can I just plop that on the same power line as the 300? Or do I need to run a separate line or get bigger wire?

Would appriciate the info!

 

The wattage rating of the amp is useless when trying to determine the proper wire size. Wattage ratings are all over the map because they're not measured in any sort of standardized fashion. You need to look at the current draw of the amp, which can still get fishy, because other than your sub amp, it's not likely that any of them will ever reach their maximum potential. But, you have to assume that they will, and choose wire size accordingly.

Consult this link when trying to determine wire size, but keep in mind that the "wattage" category is
http://www.eatel.net/~amptech/elecdisc/wire.htm

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The formula for current (Amps) is I=V/R
I-current
V-volts
R-Resistance

For wattage I*V=W
W-wattage

Running 12 volts in a car is bad news, that is why all the future vehicles will have 48 volt systems, not to mention all military vehicles are 24v. The answer to this is simple. Every wire has a certain resistance, the smaller the wire, the larger the resistance. More so for lower voltages. The lower the voltage drops on the battery due to heavy amp draw, the more current it draws to make up fot it. That can quickly lead to melting and startin fires with the wiring. So use the biggest wires you can afford, without going to 0 guage wire, unless you are running multiple amps. If you have a battery in the back then you don't need as large of a wire. Keep in mind that the ground wire size is just as important. I don't have exact numbers on me for the amoount of wattage/wire guage, but typically the larger the voltage, the more wattage potential.Look at plug wires. They flow about 35'000v at about .200A. That means 7000 watts. In a 12-14v system it would mean it would flow 500 amps, obviously not the case.

 

Use 4 gauge and be done.

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86 T/A 5.0 A4 & 2.77 gear
15.62 @ 86 mph
93 Civic 1.6L
13.5 @ 100 mph

 

Im using 8 guage wire for my 700 Watt amp and everything works just fine. Its competition wire too so it has little resistence compared to most wire. 4 guage is good but its really big and harder to hide in the molding if u r goin from the car battery to the back.

 

Im using 8 in mine. I have 2 sets running from my batter (1 for each amp) and its perfect. If your really worried about power and all, get a cap for your amp. It will help dramatically.

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What brand amp is it? What size fuse does it have on the side?

BTW, whoever told you that your "competition" wire has less resistance than other wire should have sold you a bridge to go with it.



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The IROC Homepage
<A HREF="http://www.rit.edu/~jli4307/camaro" TARGET=_blank>
View the restoration of an 85 IROC</A>
Custom Thirdgen Subwoofer Enclosures
"I didn't know a bored out Ford could go so slow" -Shenandoah

 

No particular brand of wire has more or less resistance than any other...wire is wire, unless it's made of something that conducts better than copper, such as solid gold. All you're paying for is looks and flexability (ease of installation), which are still important aspects of an install. But you can buy wire from Home Depot or the stereo shop, and they'll have just the same amount of resistance.

- Mike

 

Gold is a WORSE conductor than copper, matter of fact it is the WORST of all used!
Gold is just very resistant to oxidation.
Silver is the best, just look at and forlift battery plug. The contacts are silver plated for a reason.

 

Material Resistivity:
Aluminum 2.82e-8
Gold 2.44e-8
Copper 1.70e-8
Silver 1.59e-8

You're right copper is less resistive than gold, silver being the best...I was probably thinking of gold's resistance to oxidation. All are better than aluminum however, which is sometimes used.

- Mike

[This message has been edited by Mike92RS (edited November 06, 2001).]