PoE current question

[chillywilly]

Hi all, I have been visiting this forum for some time and have found MANY answers to my questions here by simply searching. But I cant seem to get a good answer on google or cocoontech for my question.

I had a guy wire my house for anything I may need in the future. He ran LOADS of cat5, a single coax, and some speaker cable to every room.

I have no use for all of this cat 5... so, with that said, i have about 6 runs of cat5 in every room. Can I multiple runs of cat 5 (4 - 8 twisted pairs) to power devices?

More specifically, if pair the runs to increase the effective gauge from 24 to 14 or even 12 or 10 gauge, can i push more charging amps through the cable? Or will it melt or start a fire?

i just dont know what I can use this cat5 for, I would like to put ipad charging stations throughout my house and they draw 15v, 2 amps... 24 gauge wire cant handle that much, but if I use a whole cable to transfer that power (meaning somewhere between an effective gauge of 6-8awg) will it melt? Or does it truly act as an 8 gauge cable?

 

[chedemefedeme]

You can do this safely for things that fall under "low voltage wiring". You may not, ever, under any cercumstance, use Cat5 for line voltage electricity connected to the breaker panel or any electrical outlet in your house - you WILL burn your house down and/or kill someone.

With that out of the way, can you power an iPad over Cat5? You certainly can. A company has actually made the adapter to safely combine the wire to the proper gauge for you. Just install RJ45 connectors as usual and clip these on.

http://www.vidabox.c...atures_ipcx.php

Edit: And they have this for multiple ipads at once. http://www.vidabox.com/products_ipad_wall_frame_mount_features_ipower.php

 

[tmbrown97]

There's a lot you can do using Cat5 - you can run low-level audio, video, usb, and just about anything else you can think of.

For your idea to charge devices, there are two ways to do it - one of them is to do as you're suggesting and use Passive POE. It's not a bad way to go as long as you're within specs - it's simple electrical engineering to ensure you're not pulling too much power over a wire. That said I'd be very careful not to pull too much current over the wires knowing that using 3 pairs gets you the ultimate gauge you need - if one wire breaks or slips loose, I'd sure hate to have a short! Of course you can also mitigate this with use of good fuses or power distribution blocks with breakers/fuses at the source end.

A far better way, but much more expensive, would be to use a POE-compliant switch and use POE adapters. For example, here's one that will charge an ipad or anything else that charges over USB... there are adapters for nearly anything. Just search for 802.3af adapter 12V (or whatever you're after) and you'll find options.

 

[BraveSirRobbin]

I know people gang groups of wires in Cat 5 cable all the time to increase its current capability and I'm totally against it. If one wire would break in an adapter or bundle you would have a situtation where you were running to much current through a single strand.

You would be better off running the increased current in an unused speaker wire (what gauge is it?).

 

[pete_c]

Relating to the DIY at home low cost solution (not say a Cisco POE switch commercial use configuration).

I went with Tycon Power AP style POE DIN mountable small footprint POE switches after playing some with a variety of switches for use with my Atom Based capacitance touchscreen Jogglers which draw up to 2.5 Amps with a bright screen. Totally different power POE footprint versus connectivity to a VOIP telephone.

That said the "other" side I went with small footprint TP-Link $20 POE converters. I have three configured right and they are on 24/7 and doing well still utilizing only the 802.3af standard (and the Tycon POE switches use either af or at). One D-Link "el cheapo" burned up after about a month of use connected to a Linksys WRT-54GL AP. I have pictures of both egress and ingress cases melted. I also tested a few > $50 but < $100 converters and they were about twice the size of the TP-Link, functioned fine but looked like they were put together in someone's garage.

Relating to the new CMOS IP cameras versus the old power starved CCD cameras noticed much less power requirements lately. This is just me playing with a Speco medium priced dome CCD camera (with the heater disabled) versus a similiarly priced dome generic CMOS analog camera.

 

[chillywilly]

You guys are great, thank you. The vidabox option is awesome, i'm going to look into that.

 

[N49atv]

You can easily use multiple cat5 pairs to maintain voltage drop. But paralleling them is not a good idea without maintaining the current limit.