Determine Appropriate Wire Gauge

[ROE]

Use this chart to determine an appropiate wire guage. Thanks to Memphis Car audio for the creating the chart and scionxb for finding it.



This chart can also be downloaded in a PDF format from Memphis Car Audio:
http://memphiscaraudio.com/LiveImage...ocumentURL.pdf

To figure out which gauge wire to use, determine how many watts rms will be used per Power run. If you use a distribution block, you have to account for all of amps being used for the input power run. After you find the total watts rms, locate number on the chart that's just above your total. So if your total watts rms is 1600, use the 1800. Then figure out how long of power run you will need. You will now know the appropriate size gauge to use.

[scionxb]

yeeeeeeeeeeeaaaaaaaaahhhhh boy.

[TechSys]

Only thing I can see is no 2 AWG. It jumps from 1/0 to 4.

While looking at the chart and figuring out what wire you need, I'd advise to also think of any upgrades you may do in the future and get that wire. The reason for this is less install time, less having to re-run wire, and less problems/hassle.

That's just me probably.. I have always had 2guage or 1/0 even when running just 200watts. Didn't want to rip carpet out again.

[Phelix]

I agree, if you have the money to afford 1/0 or even 2/0 then I would definately throw that in first. (example) when I got back into the car audio scene a couple months ago, I had a local company install my system, and they charged me roughly 150.00 for the Amp wiring install/kit, and a couple weeks later, when I realized I was addicted to bass.. I find out that im going to have to install all new wiring since their amp kit was only 8ga.. Pretty p/o'd about that, but thus is life..

[Phelix]

I agree, if you have the money to afford 1/0 or even 2/0 then I would definately throw that in first. (example) when I got back into the car audio scene a couple months ago, I had a local company install my system, and they charged me roughly 150.00 for the Amp wiring install/kit, and a couple weeks later, when I realized I was addicted to bass.. I find out that im going to have to install all new wiring since their amp kit was only 8ga.. Pretty p/o'd about that, but thus is life..

[big p]

the watage doesnt go high enof

[big p]

the watage doesnt go high enof

[pieszbob1]

wow i barley made it in there with 2700

[pieszbob1]

wow i barley made it in there with 2700

[devs8]

why do they have all these liek odd numbers on the chart its confusing the **** out of me LOL!

[devs8]

why do they have all these liek odd numbers on the chart its confusing the **** out of me LOL!

[sorry_i_win]

Originally Posted by big p

the watage doesnt go high enof

agreed... what would you recommend for 4600W RMS? Would 2 runs of 0 gauge be enough? And is it a good idea to run the ground wires all the way back to the battery instead of using the chassis ground? I'm gonna be running 2 batteries in the hatch tho, so it shouldn't matter, but I was just curious.

[sorry_i_win]

Originally Posted by big p

the watage doesnt go high enof

agreed... what would you recommend for 4600W RMS? Would 2 runs of 0 gauge be enough? And is it a good idea to run the ground wires all the way back to the battery instead of using the chassis ground? I'm gonna be running 2 batteries in the hatch tho, so it shouldn't matter, but I was just curious.

[brad]

Hmm... This chart is very generalized imo

One brand of 1/0 might be able to safely carry more current than another brand. From welding cable to stinger pro, they might use different materials, diameters, productions methods, etc. Which in turn can affect ratings (im talking small differences though)

I would say your best bet is to see what the manufacturers rating is. They should also give what the resistance is per foot (or figure it out yourself with a dmm), that way you can calculate your maximum length with minimum voltage drop.

Just an idea

[Gebrochen]

Originally Posted by brad

Hmm... This chart is very generalized imo

One brand of 1/0 might be able to safely carry more current than another brand. From welding cable to stinger pro, they might use different materials, diameters, productions methods, etc. Which in turn can affect ratings (im talking small differences though)

I would say your best bet is to see what the manufacturers rating is. They should also give what the resistance is per foot (or figure it out yourself with a dmm), that way you can calculate your maximum length with minimum voltage drop.

Just an idea

When it comes to power wire, all copper wire of the same guage will carry approximately the same current as any other. It's all generally the same stuff with the differences being in strand count (which may make the wire *appear* to be larger) and insulation. I definitely would not EVER go by manufacturer's ratings on wire when deciding which one to buy. Use a chart from the audio pros. A current rating is a vague concept dependent on how they measure it and the marketing department that designs the packaging is likely to randomly over-inflate the numbers just to make it sell better than other wire of the same kind.

[brad]

Originally Posted by Gebrochen

When it comes to power wire, all copper wire of the same guage will carry approximately the same current as any other. It's all generally the same stuff with the differences being in strand count (which may make the wire *appear* to be larger) and insulation. I definitely would not EVER go by manufacturer's ratings on wire when deciding which one to buy. Use a chart from the audio pros. A current rating is a vague concept dependent on how they measure it and the marketing department that designs the packaging is likely to randomly over-inflate the numbers just to make it sell better than other wire of the same kind.

Notice how I said small differences... very small

Also, this chart is not specifically for copper wire. Thus the reason for my post.

And no, a current rating is not a "vague concept", speaker rms, peak, t/s parameters, are vague concepts dependent on how they measure them/calculate them. A current rating is an important spec, if it were improperly rated/inflated, a consumer, such as an electrician might have a hard time.

Strand count is also an important specification, not just for flex, as some people confuse it as. The use of stranded conductors adds lots of surface area. And in AC ~ situations, finer stranded wire mitigates current surfacing, the skin effect. This is important with high freqency applications as the effective resistance of the conductor tends to increase with the frequency of the current. However, this topic is highly debated by audiophiles, I would say not audible effects, but still effects

Its funny that you mention to look at charts from the "audio pros" as I have looked at many... all of which are differnt =0

Power Wire Gauge Guide
Total Power 15 Ft 17 Ft 20 Ft 22 Ft 25 Ft
100 Watts 10 10 10 10 8
200 Watts 8 8 8 8 8
300 Watts 8 4 or 8 4 or 8 4 or 8 4 or 8
400 Watts 4 or 8 4 4 4 4
500 Watts 4 4 2 or 4 2 or 4 2 or 4
600 Watts 4 2 or 4 2 2 2
700 Watts 4 2 or 4 2 2 2 or 1/0
800 Watts 2 or 4 2 2 2 or 1/0 1/0
900 Watts 2 2 2 or 1/0 1/0 1/0
1000 Watts 2 2 1/0 1/0 1/0






http://the12volt.com/info/recwirsz.asp

[Gebrochen]

Originally Posted by brad

Notice how I said small differences... very small

Also, this chart is not specifically for copper wire. Thus the reason for my post.

It doesn't say copper, but aluminum would be the only other practical option and the amp capacity of Al would be significantly different. My believe is that this chart is definitely for copper.

And no, a current rating is not a "vague concept", speaker rms, peak, t/s parameters, are vague concepts dependent on how they measure them/calculate them. A current rating is an important spec, if it were improperly rated/inflated, a consumer, such as an electrician might have a hard time.

Then what determines current rating? The point at which resistance goes up 5%? 10%? When it heats up to x degrees F? When it burns in half? Unless you have a spec that the current rating was measured at, it could easily vary. Just like speaker SPL, sometimes they don't tell you if that's at 1w/1m or 2.9 volts.[/quote]

Strand count is also an important specification, not just for flex, as some people confuse it as. The use of stranded conductors adds lots of surface area. And in AC ~ situations, finer stranded wire mitigates current surfacing, the skin effect. This is important with high freqency applications as the effective resistance of the conductor tends to increase with the frequency of the current. However, this topic is highly debated by audiophiles, I would say not audible effects, but still effects

Car audio power is DC, not AC, so skin effect does not happen. Also, Skin effect is irrelevant in the audio spectrum as you mention. There have been numerous posts discussing this ad nauseum already and I actually linked in one of them to a huge whitepaper discussing every aspect possible with the conclusion that the difference was negligible... any way, the main point is this isn't relevant at all to DC power wire.

Its funny that you mention to look at charts from the "audio pros" as I have looked at many... all of which are differnt =0

I would expect them all to be different, but getting all your information from one chart means the same guideline is likely to have been applied consistently versus reading packaging from 10 different manufacturers. My point wasn't about picking out the right guage of wire, it was on the question of different brands/strand-count of the same guage being a factor in amp capacity.

[brad]

Originally Posted by Gebrochen

It doesn't say copper, but aluminum would be the only other practical option and the amp capacity of Al would be significantly different. My believe is that this chart is definitely for copper.

So, this chart is for copper.... ok, so everyone here must use copper wire!

problem solved

.............

Originally Posted by Gebrochen

Then what determines current rating? The point at which resistance goes up 5%? 10%? When it heats up to x degrees F? When it burns in half? Unless you have a spec that the current rating was measured at, it could easily vary. Just like speaker SPL, sometimes they don't tell you if that's at 1w/1m or 2.9 volts.

Ok, in car audio, a general rule of thum on wire size/capabilities will suffice. But, in careful engineering the insulation temperature limit, thickness, thermal conductivity, and air convection and temperature should all be taken into account.

Its alot more detailed than you think, you sound as if wire ratings are a joke or a mere estimate, go tell that to an electrician or the US military spec.

The current rating of a cable or wire indicates the current capacity that the wire or cable can safely carry continuously.

If this limit, or current rating, is exceeded for a length of time, the heat generated may burn the insulation. The current rating of a wire is used to determine what size is needed for a given load, or current drain.

The factors that determine the current rating of a wire are the conductor size, the location of the wire in a circuit, the type of insulation, and the safe current rating. These factors also affect the resistance in ohms of a wire-carrying current.

Another factor of governing current rating is the conductor size. An increase in the diameter, or cross section, of a wire conductor decreases its resistance and increases its capacity to carry current. An increase in the specific resistance of a conductor increases its resistance and decreases its capacity to carry current.

Yet another factor is wire location. The location of a wire in a circuit determines the temperature under which it operates. A wire may be located in a conduit or laced with other wires in a cable. Because it is confined, the wire operates at a higher temperature than if it were open to the free air. The higher the temperature under which a wire is operating, the greater will be its resistance. Its capacity to carry current is also lowered. Note that, in each case, the resistance of a wire determines its current-carrying capacity. The greater the resistance, the more power it dissipates in the form of heat energy.

Conductors may also be installed in locations where the ambient (surrounding) temperature is relatively high. When this is the case, the heat generated by external sources is an important part of the total conductor heating. This heating factor will be explained further when we discuss temperature coefficient. We must understand how external heating influences how much current a conductor can carry. Each case has its own specific limitations. The maximum allowable operating temperature of insulated conductors is specified in tables. It varies with the type of conductor insulation being used.

The insulation of a wire does not affect the resistance of the wire. Resistance does, however, determine how much heat is needed to burn the insulation. As current flows through an insulated conductor, the limit of current that the conductor can withstand depends on how hot the conductor can get before it burns the insulation. Different types of insulation will burn at different temperatures. Therefore, the type of insulation used is the third factor that determines the current rating of a conductor.

Originally Posted by Gebrochen

Car audio power is DC, not AC, so skin effect does not happen. Also, Skin effect is irrelevant in the audio spectrum as you mention. There have been numerous posts discussing this ad nauseum already and I actually linked in one of them to a huge whitepaper discussing every aspect possible with the conclusion that the difference was negligible... any way, the main point is this isn't relevant at all to DC power wire.

Yes, I did mention.... I was just stating facts

however, amp to speaker and rca's are AC

Originally Posted by Gebrochen

I would expect them all to be different, but getting all your information from one chart means the same guideline is likely to have been applied consistently versus reading packaging from 10 different manufacturers. My point wasn't about picking out the right guage of wire, it was on the question of different brands/strand-count of the same guage being a factor in amp capacity.

Guideline of what? You said yourself:

Originally Posted by Gebrochen

A current rating is a vague concept dependent on how they measure it and the marketing department that designs the packaging is likely to randomly over-inflate the numbers just to make it sell better than other wire of the same kind.

If these ratings are inaccurate, inflated, or whatever, then why are we looking at these charts? How in the first place do you think they make these charts? Do they just guess current/wattage/maximum feet ratings because manufacturers make inaccurate inflated ones?

My point is of both , choosing the right size and difference in brands/styles, are you just suppost to pick which chart you think is the more accurate one?.... however, I would argue that they will suffice for our application, car audio. I would still reccomend to look at the manufacturers spec and I would still argue that these charts are too generalized.

[Gebrochen]

[quote=brad]So, this chart is for copper.... ok, so everyone here must use copper wire!
[quote]

Do you know anyone in car audio not using copper wire? Unless you're rich enough to buy silver, you should probably stick to copper.

Ok, in car audio, a general rule of thum on wire size/capabilities will suffice.

I was under the impression that this thread was about car audio power wire.

But, in careful engineering the insulation temperature limit, thickness, thermal conductivity, and air convection and temperature should all be taken into account....
....
The factors that determine the current rating of a wire are the conductor size, the location of the wire in a circuit, the type of insulation, and the safe current rating. These factors also affect the resistance in ohms of a wire-carrying current.
...
Another factor of governing current rating is the conductor size. An increase in the diameter, or cross section, of a wire conductor decreases its resistance and increases its capacity to carry current. An increase in the specific resistance of a conductor increases its resistance and decreases its capacity to carry current.
....
Yet another factor is wire location.
...
The higher the temperature under which a wire is operating, the greater will be its resistance. Its capacity to carry current is also lowered. Note that, in each case, the resistance of a wire determines its current-carrying capacity. ...

You've typed out a lot of good information I knew already, but much of it is superfluous to the point we're talking about (current capacity of different brands of the same guage wire). You talk about location, ventilation, and coductor size (we're talking about same size). Regarding location and ventillation, you're not going to see that mentioned on any chart and it applies to any wire, so again, not relevant to the discussion here. I'll extract one point you made: "Note that, in each case, the resistance of a wire determines its current-carrying capacity". Yes, I agree. And all 1/0 copper wire is going to have the same resistance per foot regardless of brand or strand count (let's not debate over hundredths of a percent depending on purity, etc).

however, amp to speaker and rca's are AC

This thread is about power wire. Best not to confuse people with information that isn't relevant when picking out power wire, especially when we both agree that worrying about this is a bit anal.

Guideline of what?

All of the charts are somewhat within range of each other. I don't think you could go wrong with any of them. You can use them as a guideline and go higher if you wish.

If these ratings are inaccurate, inflated, or whatever, then why are we looking at these charts? How in the first place do you think they make these charts? Do they just guess current/wattage/maximum feet ratings because manufacturers make inaccurate inflated ones?

I'm saying you should look at an electrician's chart and not go by a number the manufacturer placed on the packaging. Yes, in a way they do just guess, which is why all the "professional" charts will vary. However, my bet would be that the manufacturer will always go with the highest possible number and not what would be "best" (definition of best not available) in a performance setting.

I would still argue that these charts are too generalized.

No more generalized than the information you'll get from the manufacturer. If your wire is heating up enough to have any risk of burning insulation, you've exceeded the rating by far.

[dark666apoc]

so many big words haha

[Gebrochen]

Originally Posted by dark666apoc

so many big words haha

Oops, sorry. I forgot about the 3-syllable rule.

... my next patent. Injecting non-corrosive cooling fluid under pressure through a wire using the airspace between conductors. ... and yes, I'm being silly. Just another idea for some manufacturer to use in order to get you to pay a high premium for their wire.

[tron12]

i need help i cant find it here.my amp for front and rear is 200w and its in 8 guage wire my amp 4 subs is 800w and its in 4 guage wire can i get more bass if i'll change the 4 guage wire on my subs amp??im new dont know to put my question thanks hoping the i'll get a reply

[tron12]

sorry 4 guage in 200w and much tinner on the subs amp

[dRaGGin loW]

they teach us the lowest wire you should ever run is 4AWG so yea i wouldnt run 8 at all

[Phoenix]

Originally Posted by XBlazer01

they teach us the lowest wire you should ever run is 4AWG so yea i wouldnt run 8 at all

umm, running 8 gauge is fine if you aren't running a really ballsy amp.