2000 Expy - Advice on Wiring Lights

[soldatlamour]

Thermo - thanks for the advice

I don't weld, but I found a welder nearby. He's going to weld 12 tabs ( 4, 3, 3, 2) to my basket rack. I bought 20 tabs for a total of $3.40, and he's going to charge me only $60 to weld. I feel happy about it.

Please comment on my suggested plan of attack for wiring (diagram attached). I want to have a Master switch that "turns on" the other switches. My thought is that I'll have to run only one Power and one Ground (from the M switch) - the other switches' powers/grounds will run a few inches to the Master. Then the 4 switches will run to their respective relays.

I can split the load on S1 to two separate relays, right?

I plan on using 12 AWG wire from the lights to the relays. Let me know if that's OK. Also - with 4 lights ( all lights are 55w ) on the front, 3 on the sides and 2 on the back, will 25amp fuse for each of the relays be sufficient? (Since I'm splitting the front into two relays, perhaps the focus should be on the 3 55w side lights per relay ? )

What size wire should I run on the switches? Is a 10amp fuse good for the switches?

I've found a pocket in the back of the vehicle where I will put a Power distribution center. I plan on making a quick connect between the wires on the rack and the wiring from the distribution center (essentially, the 5 "loads" from the relays and a main grounding wire).

Thank you in advance for your help.

 

[soldatlamour]

Updated Drawing

Thermo,

I found a fatal flaw in my diagram.

On my Master switch I didn't have a "load" going anywhere. I had all of the other Switches powered via the 12v source to which I wired the Master.

The attached has the fix (correction is shown in the green wire).

Am I almost home ? haha

 

[Thermo]

As for the wiring, based on what you have wired up, I would say to run 16 gauge wiring for the lights that are paired up and then 14 gauge wiring for the sets of 3 lights. The 14/16 gauge wiring really only needs to be between where you are splitting the power off from (fuse box?) to the main power part of the relay, from the output of the relay to the lights, between the lights, and from the lights to ground. The actuation wiring for the relays only needs to be 22 gauge wiring. The actuation wiring is very low current stuff, so, that can be smaller gauge wiring.

As for fuses, I would say to run 15 amp fuses for the pairs of lights and then a 20 amp fuse for the sets of 3 lights. But then, the 25's will work too. Rule of thumb is to set the fuse rating at about 125% of the maximum steady state load. Since each of the lights will pull about 5 amps when running, this is about as close as you are going to get.

One final helpful hint is to get yourself 5 colors of wiring. You want a fair amount of black wiring for all of your grounds (obvious to the electricians), but then you will want 4 other colors (red, yellow, orange and blue for example) to run between the relays and the lights. Why the different colors? Easy, when you get that bundle outside of the truck, which wire controls what? Having different colors allows you to figure out which wire goes to which set of lights. So, for example, the red wire would go to the lights powered by R1, the orange wire would go to those from R2, yellow to those from R3, and the blue to those from R4. The same convention should be used when running the wires between the switches and the relays to turn the relays on and off. You will be very thankful for this if you have problems as you will be able to just look at a wire and know where it should go and what power is should have on it at any given situation. I can't tell you how many times I have had to correct things for people when they used 200 feet of the same colored wire for all of their stuff. Makes figuring things out lots of fun.

 

[soldatlamour]

The Simple Ideas are the Brilliant Ideas

Thermo,

Thanks for the great advice on different colored wiring. That is a fantastic idea.

Can you confirm that on my switch panel I can tie-in the four switches to the master switch. That is, have only the Master wired to a 12v source and then when I flip it 'on' it provides power to the four Switches?

thanks