max rms -v- 1/0 cable ?

[big scott]

hi guys,

what is the max rms power ( amp power ) for a run of say 17' of 1/0 wire ?

right now i have 1-4ga and 1-8ga running to the back. well i want to run 1/0 to the back, and im upgrading my sub's and sub amp. so i need to know what the max is for that wire so i don't overload it.

is there bigger wire then 1/0 ?

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[bbeljefe]

You can't really relate power output to wire size because there is another variable in play. That variable is amplifier efficiency. In a perfect world, an amp would produce as much power as it consumes but in the real world, that's not possible. Class D efficiency is typically ~70% if the amp is coupled with its optimum load so in that case if our amp is consuming 100 watts of power it is producing 70 watts. When you drop the impedance below optimum, efficiency also falls and the amp needs more power in order to produce the same power. Likewise with low voltage. If the amp can't get optimal voltage, it will lose efficiency.

So with that in mind, we need to consider current draw when sizing wire. If your amp consumes 100 amps of current at full power, then your wire needs to be capable of carrying 125 amps minimum, as having about 25% headroom is important to avoid heating the wire and causing fuses to blow. Another consideration with wire is whether or not it's CCA (copper clad aluminum) or ofc ("pure" copper). The former is a lot less expensive but it also won't carry as much current and, it has more resistance than the latter so voltage drop becomes a consideration as well.

With all that said, you can use a rule of thumb when sizing wire and it's something like this... 1/0 car audio CCA is good for about 250 amps and 1/0 car audio OFC is good for about 325 amps. And, that safely translates to about 2000-2500 watts for CCA and 3000-3500 watts for OFC.

As for the cost difference between the two conductors, here's an example from Sky High Car Audio's ebay site...

1/0 CCA price per foot: $2.31

1/0 OFC price per foot: $3.64

 

[tprj82 10+ year member]

Yes I believe wire goes up to 1000 mcm which is similar to what you see on power lines running down the street. Typically in the audio world we cap it around 4/0 welding wire which is nice and flexible for its size

 

[shauncox26]

how much can 4/0 handle amp wise?

 

[Popwarhomie 5,000+ posts]

Sky high has 2/0 which is around the size of 4/0 welding wire.

They have amp ratings on their site.

Knu 1/0 CCA is rated 250 amps for a 20 foot run.