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Discussion Starter · #1 ·
OK, I have done quite a bit of research but have a few questions for my electrical friends. I am wiring up some lights that are on my ARB bumper, a CB radio, a 12v outlet for my rear cargo area, and a light out back. I have decided to use an aux fuse box to clean things up a bit and not have so many wires coming off the battery. I think I am going to use a bluesea fuse box for 6 items and here is my question, I run a main power wire from the batt to the fuse box and then wire each component to the fuse box using relays, then relays to the switches. I think I have that right...how do I go about selecting the appropriate size wire from the battery to the fuse box and also the appropriate size inline fuse?

I think I should go with approximately 4ga wire to the fuse box from the battery with a 100amp inline fuse...does this sound safe? Each accessorry should also have an appropriate size wire to the relay...is there a calculator to find out the right size?

Honestly, I am not going to be drawing too many amps from 3 sets of lights, a cb, and a 12v socket; however, I want to be prepared and safe. I am also going to be wiring up a power inverter and my winch to my battery directly...what, if anything, should I look for there?

Thanks in advance!

Chris :D
 

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I used a cheap fuse block from autozone THIS ONE mounted to the firewall and ran a 6 gauge starter cable to it. I still have to put a fuse on it, keep forgetting to get one. Wires to the fused side dont need to be too big, 14 gauge for the lights and maybe the accessory socket, the rest can be smaller. There are calculators online but can take some searching. Need to know the max amperage you plan to draw and the distance.

For the inverter and winch, get some welding cable. I used 4 gauge welding cable to run to the back of my rodeo for the 1000 watt inverter with a 100 amp fuse near the battery. My reverse lights on my roof rack also are powered off of that line. Welding cable is nice because it's very flexable which makes it easy to run and there are a lot of strands inside the wire which helps with current flow. The electrons travel along the outside of the wire strand so more strands = easier flow.

 

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I have several power sucking accessories on most of my vehicles. I use amplifier hookup wire from walmart to go from the battery to a 100 amp mega fuse. Then I go from that to a terminal strip. I hook any accessories to the terminal strip with appropriate sized wire and then run an inline fuse next to the terminal strip.

 

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Now I understand what you were texting me about. I would run one larger sized wire (I think I got one you could use out of Project Winning's amp set up) to the new fuse block. The fuse block will be fused so you don't really have to put an inline fuse in the large sized wire BUT its not a bad idea. Find a general fuse block to run the large wire to. From each fused terminal on the fuse block, run a wire to the "30" terminal on the relay. Run a wire from the 87 side of the relay to the accessory (i.e. the lights). Connect the accessory to a ground and that circuit is done. Now to activate it's "switch" (i.e. the relay), you have to make another circuit to activate it. I'd dedicate one of your 6 fused circuits to run the switches. So from that fused terminal on the fuse block, run a wire to your switch and another from the switch to the 86 terminal on the relay. Then another from the 85 terminal to the ground.

As for selecting the appropriate sized wiring, the lights should say how much amperage they need (or you can see the existing wiring and increase a size). Look at your existing fuse block. Everything has 5, 7.5, 10, 15, 20, 30 amp fuses. What has the 30 amp? How many items are on it? The head lights will be on their own and will probably be higher than the brake lights. Find comparable items to what you are wiring and use similar fuses.

These will help you size the wires:
Gauge Amps
1/0 350
2 225
4 150
8 100
10 60
12 40
14 25
16 15

So with that info, you won't need welding cables unless you need large number of amps. If you are doing headlights, find the watts, divide by 12 volts to get your amps. So (2x 60 watt bulbs)/ 12 volts = 10amps (yours will be different). So run a 16 gage wire with no larger than a 15 amp fuse. Remember, the fuse protects the wire; not the accessory. Well, it does protect the accessory, but the idea is that the wire doesn't turn into an electrical coil and catch on fire- the fuse burns out before that happens. But make sure the fuse will not carry the maximum amps of the smallest wire in your circuit.

Here is a fuse block that would have 6 circuits and the basic layout for it.
http://bluesea.com/files/resources/inst ... 8_5033.pdf
How to wire a relay.


I don't mind helping with this if you get stumped.
 

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Discussion Starter · #5 ·
OK...That is making sense. Yeah, when I start tackling this I will of course give you a call to pick your brain. If PW (Project Winning :mrgreen: ) has a good enough sized cable, I may take it.
 
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