Selecting Amp Kits

Once you have selected your amp, you need to select an amp kit to wire it into your vehicle. This includes power and ground wire, a fuse, remote turn on wire, RCAs, speaker wire, and in some cases a few extras or a few of these components missing depending on the kit you get.

Amplifier installation kits, or wiring kits, usually include all or most of the things you need to install your amp, but you don’t need the full kit if you already have most of what you need; you can go buy whatever you’re missing separately. If starting from nothing, it’s usually a lot cheaper to get a kit. Also make sure the kit you buy includes what you need. For example: most kits only come with one set of RCAs. This is fine for a sub installation, but you will need another pair if you plan on doing 4 speakers on a 4 channel amp.

What’s in the kit?

KnuKonceptz 4 GA OFC Amp Kit
Check out the KnuKonceptz Kolossus 4 Gauge OFC Amp Kit on Amazon

Amp kits will include the wires, cables, fuse holders, and connectors you need to install your amp. Some include more pieces than others. This 4 gauge KnuKonceptz amp kit (check price on Amazon) includes everything you need to get your system hooked up and sounding good. Cheaper kits can be had, but the wires won’t be true AWG size, will most likely be copper clad aluminum (CCA), won’t carry current as well as good, name brand pure copper kits, and will have cheap RCAs.

It’s definitely worth the extra price to upgrade to pure copper wire like this Rockford kit. When looking for a pure copper amp kit, some companies will call it 100% oxygen free copper, pure copper, or OFC. These provide the best conductivity and least resistance compared to CCA.

Power Wire
This will be the longer of the two thick wires in your kit. It runs from your battery to your amp.

Ground Wire
This will be the shorter of the two thick wires, usually less than 3 feet. This goes from your amp to the chassis or body of your car.

Remote Wire
This the long single wire in the kit, usually blue. It runs from a switched 12V source, like the remote turn on wire on the back of aftermarket radios, to your amp.

Speaker Wire
This is the wire that is actually two wires together. Obviously this goes from your amp to your speakers, one side to positive, one side to negative.

RCA Cable(s)
The RCAs are signal cables that run from the output on the back of your head unit, or low level converter (more on that later), to the input on the amp. These probably vary more than wire quality does (as long as you go with pure copper). You don’t want to skimp on RCAs or you could possibly get engine noise or other signal quality problems.

Fuse Holder
This is what protects your car, battery, and amp from getting fried if something goes wrong. This should ALWAYS be installed and as close to the battery as possible, usually no more than 18″.

Various Connectors and Terminals
Most kits will come with wire connectors and terminals so you can connect the wires where they need to go.

How to pick what kit you need

Amp kits are sized by the power and ground wire. For example, if you buy an 8 gauge amp kit, the power and ground wire will be 8 gauge. The speaker wires are usually 16 AWG or less, and the remote wire is usually 18 AWG.

Assuming the kits you are looking at are a good brand with true AWG copper wire, here’s the basic wire size you need based on your power requirements:

amp wire gauge chart
Image from Crutchfield’s great post on the subject:

Just match the max amperage or fuse rating on your amp to the amperage on the chart, find out how long your wire is going to be, and you can find out what size wire you need. If you don’t yet have an amp but know about what power your amp will be, you can use the general rules below:

For a Class D amp (assumes 75% amp efficiency and 13.8 volts): 

\begin {aligned}
Amps={Total \> RMS \> Power \above {2pt} 0.75 \> x \> 13.8 \>VDC}
\end {aligned}

For a Class AB amp (assumes 50% amp efficiency and 13.8 volts):  

Amps={Total \> RMS \> Power \above {2pt} 0.50 \> x \> 13.8 \>VDC}

You can also find a calculator here that will tell you the minimum wire size needed for your installation.

If you are ever unsure, or are going with a cheap kit, it is probably best to just jump up a gauge, or if you go with CCA instead of pure copper wire it’s recommended to go up two wire sizes to achieve less resistance. You can’t go wrong by getting bigger wire (smaller gauge) just don’t ever get smaller than recommended. That can cause the wire to get too hot from trying to pull more current than it’s designed for and possibly cause a fire.

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