DC Power Over Ethernet (Injector Adapter) For: Router, AP, Switch, Hub

I created this adapter so that I could use a UPS (battery backup) located upstairs, to power a network switch located downstairs. The network switch provides a network/internet connection to my Xbox360, Modded original Xbox, and goes through the basement to a joining house. This solution keeps all of the network equipment powered up, in case I lose power.

This can also be used to power a router, switch, access point or hub that is located in a area that does not have power. For example, you may want to use this method to relocate a WiFi access point to the attic or in a drop ceiling at the office.

The Commercial Linksys POE power injector adapters go for around $40. Power injector adapter

I had the materials on hand which is what prompted me to do this project. You should be able to pick up the materials for under $8...given that you already have a spare Ethernet cable lying around.

Materials needed:
2 - RJ45 Ethernet (cat5) wall plate jacks.
1 - RJ45 Ethernet (cat5) patch cable.

Step 1: What wires are actually used for data?

A ethernet (cat5) cable has 8 wires. 4 of the wires are used to transmit and recieve data. The other 4 are not used. The "unused" wires will carry the power from the AC adapter.

Comments

[Nazgulmagefreak]

For future reference, what is the max amperage and voltage you can run over the ethernet cable.  Is it safer to install a fuse somewhere if you are putting a router in a location that is not easily accessible?

[ghz24]

I'm pushing 13.6 volts (to a12 volt wrt54g) used 4 wires 2 for positive and 2 negative on a 100 foot cat5 cable.
But the linksys routers run on any voltage from 5 to 18 volts (I'm not brave enough to try above 18 volts)
The main problem you might have is "voltage drop" with low voltage routers like 5-7 volts especially. you may need to use a higher voltage wall-wart to account for the drop.

I don't remember the exact answer in watts you could pull through 2 strands of cat 5 but mine was way inside the safety buffer. but if you are going 100 meters on a single strand with a low voltage router you could have troubles. Most wall-warts provide less than an amp of current.

[grtyvr]

Voltage is not as important as ampacity....

http://wiki.xtronics.com/index.php/Wire-Gauge_Ampacity

Sending too much current will melt things. Since in cat5 we have a bundle of wires I would use the eclosed ampacity in the above referenced table. Most of the powered switches and routers that I have seen have a rated power of 1.5A or less. So if your cat-5 is 24guage or better, I would feel safe using it.

[rjwarpath]

I am not sure what the Max voltage is. The network switch that I am powering over the ethernet  is about 7volts.

[DieCastoms]

 I did something very similar to this to carry telephone over the WB/B pair of a buried Cat5 to my camper...  should I both to make an instructible?

[wokwithme]

This is DC Power over Ethernet. It's not the same as commercial POE which is a misnomer because POE uses AC power to carry Ethernet (10/100) Signal.

[rjwarpath]

I updated the title of the instructable and removed the reference to it being similar to commercial POE adapters.

[wokwithme]

Actually the Commercial POE is the misnomer since theirs should be called EOP (Ethernet over Power). The Industry also has POE Injectors which is what yours project is. They also call them POE which confuse the heck out of consumers.

[westfw]

You can use this to send power over your ethernet wiring if you control both the power provider and power consumer.  But it isn't "real PoE", and won't be compatible with commercial PoE devices.  Real PoE has a complicated and expensive protocol associated with requesting/supplying power, uses 48V over the wires (requiring a relatively expensive DC/DC converter at the consumer) and can actually send power and data over the same wires.