Am I an idiot? Want to use ethernet for lightswitches

Anyone who knows more than me please let me know if I'm being dumb:

I'm tired of punching holes in my firewall, the standard grommet is already Swiss cheeze from power for my head unit amp, more power for my subwoofer in the back, anytime camera/front camera, probably forgetting something else...

I want to add a few switches in the future for lights/other goodies. And an ethernet cable has 8 wires bunched together...

My idea is use each pair for 1 switch (relay not power) to give me 4 switches for 1 smallish wire run.

Am I missing something?

 

Will they handle the amps?

 

That's exactly what SPod uses. Check them out or send them a message to see how their setup works

 

There are digital control panels. Not cheap but Google is your friend.

 

Don't use solid wire ethernet. Make sure the stuff you use is multi stranded. Check the gauge vs amps you're using

 

Yes, also didn't want to pay out the a$$ for what amounts to a better thought out raspberry pi.

From my earlier googling automotive relays take about 200mA or so to close the contacts. Ethernet is about 24gauge for each wire which according to a random chart I found can carry 1 amp.

Just figured it was too good to be true and I was going to make a big mistake.

 

Keep an eye on temperature ratings. Most Ethernet cables are not rated for automotive temp range, and higher than typical currents will increase the warming of the conductors.

1 amp over 24 Awg for a short distance and time is probably okay, but if you pull an amp for each conductor in a sustained manner, I’d expect a failure of the cable.

 

If you have a decent ohm meter, you can calculate the ohms/foot for the wire you're using. One you know that, you can calculate the voltage loss for the distance and how many watts/foot of heat the wires will be taking.

 

You could just take some appropriate gauge for your run/amp draw TXL type wire and concentrically twist and put it in a Raytheon heat shrink jacket or some of the like mesh loom and be a pretty slim run of wire.

Do you have the passenger fire wall side 3/4” grommet up toward the cowl available? On my Tacoma I drilled that pre-existent hole out and added a Daystar boot to allow much more wire to be run if needed.

 

Are all those add-ons pigtailed off the battery???

 

You're not an idiot, great minds think alike. I used two CAT6 cables in my dash panel. One carries camera signals (that mod is still in progress) and the other powers different relays for this panel:



I have the +12v as a tap off of a circuit that powers on in the truck using an add-a-fuse - that 12v source goes to power each switch. When a switch is pressed, that current goes over a line of the ethernet to the relay bank in the engine bay, where the relays are. The relays then put 10-30A to the component, depending on what it is.

It was really easy and has worked great for a couple of years now. The power draw of the relays is so low that it's perfectly fine over a short ethernet run and saved me running a bunch of cables. I can probably dig up more pictures or my wiring diagram if you care, but if you understand relays and switches and current, it's probably not going to be anything you don't know already.

 

stranded and outdoor jacket, don't know if it exists

 

Oh snap. Your right. If I run a single 12v from my fuse box, it can provide power and I can run 8 switches instead of 4.
Thanks all. Good suggestions!

I've got a dry box with a 12 port bluesea fuse box and all my audio fuses and a big disconnect, and a 100A relay to power the bluesea. Still need to run a wire inside to actuate the big relay since there's nothing in the engine bay fuse box suitable.