I think I've got it,yet not quite

I realize that I have probably asked some pretty dumb questions but I think I am almost out of everyone's hair.  Thanks for baring with me. The following is the way I propose to hook up the three amps.  I need advice from you to see if I am going in the right direction.  I also want to know if I am correct on how I plan to ground the amps.

Bear in mind,I have not chosen amps as of yet, but  they will total no more than 600 watts nominal.

My Plan: I am going to run 4 gauge cable from the battery's positive and the fuse I will use will be the amperage sum of the three amps. This will also be  fused within 16 inches of the battery or as close as possible. Then to a distribution block in the trunk, that will split to the amps using 8 gauge wire.

Now the grounds for the amps will be  8 gauge yet how to ground them, I am not sure. I am grounding  them all to the same spot of course! I am not sure if I should drill a hole into the metal on the parcel shelf or into  the bottom of the trunk and attach a bolt to that hole. Then I can attach a "ring connecter" to the end of each 8 gauge ground and attach to that bolt ...will that work well?

Also, the remote turn on lead from the H/U will be connected to a 30 amp SPDT relay connected to a constant 12 volt positive in the car which will be fused also to the sum of all three amps. Am I right on that one? The remaining connections on the relay will be ground, head unit remote wire and the power output to the three amps which can be fused optionally from what I understand.

Ok, that is how I am going to hook the amps up. I hope I am on the right track.  Glance over what I have typed and give me some feedback, if you will.

All signal wires and power wires will be seperated as far apart as possible.   Thanks for your help.

Manning

Be sure to check the power requirement for the + input of whatever amps you buy.  Some require 4 gauge, some are 8.  Keep this in mind when when you run you distribution block.  If you've already purchased a block that splits from 4 gauge input to 8 gauge output, and your amps require 4 gauge, then just use 2 pieces of 8 gauge.  That usuall works well with little power loss, and it saves you from having to buy another distribution block!

As for the ground.... Use the same gauge ground as you use for the + input into the amps.  You can simplify it by using another distribution block like you would with the + (multiple grounds going into the block, with 1 output ground going to the frame).  Ground to the bottom of the trunk.  Parcel shelves are not a good choice to ground too unless you have absolutely no choice.  Always ground directly to the frame, not to something attached to it.  As far as using a bolt, remember that its the frame that you're grounding too, not the bolt.   So make sure that there is enough bare metal on the frame around the bolt for the ring connector(s) to make contact with.

Squirrel that really helped clear things up a lot. I actually was planning on just bolting ground to the parcel shelf. Now I will attach it to some bare metal on the trunk deck.

 Will you glance over what I wrote about hooking up a relay to power up three amps from the head unit's power cont. wire and tell me if that is right?

I have searched the archives of this site for info on this, and did a search on it as well. I did find a lot of info, yet for some reason I am not entirely sure how to correctly hook up a relay for this purpose.

I think once I understand that I am out of the woods.

thanks again,

 Manning

Please, someone else answer this because I am not sure and would like to hear the answer,but, wouldn't it be too high to fuse the constant 12v (for the relay to the turn ons) as the same as the inline from the batt? (sum of amplifier fuses), and also, would you need a relay there for 3 amp turnons?

Alright before you purchase any cable I would get the amps. Because if you end up getting amps that will pull a higher load than you anticipated then you will be stuck with the cable. 2nd different amps have different hookups for different size cable. But for my calculations I will take half of your “normal power” and use it as the rms so if you had 900 watts rms you would be putting 75 amps on your main cable. If each one of your amps was 300 watts rms then it would put a 25 amp load on its cable. So with a 4 gauge main and 8 gauge to the amps you will be more than safe. For the amps you want the ground cable to be as short as possible. Also be sure that you use the same size ground cable for your ground as you did for the power since it will pull the same amount of current as your main power cable. I like to use a central point to prevent ground loops. As far as the relay goes you do not need one to turn on three amps but if you want to add one here is the diagram