Installing head unit, speakers and amp

[Fountain Family]

I bought a boat that was built from the factory without a head unit or any speakers.

I bought a Head Unit, Amp and Speakers to install in the boat and have a couple questions.

I am going to run a hot wire from the battery to a switch on the dash then to the head unit. What gauge wire should i use for that and what size switch? Will any switch work or should i be looking for something specific?

I also wanted to know if i could ground the head unit to the amp since i am running a ground wire from the amp to the Battery. If not i can run a ground from the head unit to the Battery but what gauge wire should i use?

These may be silly questions but im just not 100% on what i should do.

Thanks!

[US1 Fountain]

Why do you want to put a switch in your power wire? Guess I shoulda asked, you are not talking about the main power leads, but more the trigger leads?

[Fountain Family]

Why do you want to put a switch in your power wire? Guess I shoulda asked, you are not talking about the main power leads, but more the trigger leads?

My thought was to turn it on and off...

[ziemer]

Your head unit should have a constant power lead (larger gauge wire) and a switch or turn on lead that will be a smaller gauge wire.

The main power typically goes directly to the batt with a fuse but on a boat that doesn't always get used it should go thru the batt switch. The turn on lead would go to a switch on the dash.

Amp will also have similar wiring.

Basically setup like a relay. High amp draw direct to battery controlled by a low amp switch.

[Griff]

If you are not running the internal amp on the head unit, then the wire gauge is not really even issue. The head unit will not draw hardly any power. Mine head unit is wired from the factory just as you are proposing doing to yours. I think I have a 15 amp switch and it powered right off the other dash power. I think the wiring is 12 or 14 gauge. If you are actually going to use the internal amp on the head unit, then I would probably run 10 gauge wire or so. A 15 amp switch should still be fine. Chances are you have a main power and ground behind the dash that you can tie into. A 15 amp swithc is overkill anyway. The inline fuses for head units are usually 3-5 amps.

[ThisIsLivin]

You want to run the main power and switched power separate or the head unit may forget it's settings. Like when you disconnect the battery in your car. You said your running a separate amp with a head unit, I have 1/0 running from the battery to a circuit breaker and then to a distribution block to supply my amps and head unit. Ideally you want to run your subs on a separate amp for best performance. When running power wires for a sound system you don't size them for current capacity, you size them for voltage drop. This typically means that you will step up the gauge about 3 sizes depending on run length. Make sure you use quality cables, finely stranded annealed copper wire has less resistance. IF you are using a manual switch to control the switched input on the amp and head unit, they only take a couple amps total max.