What Is The Maximum Power That Can Pass Safely On Cat5e?

IEEE 802.3af/at/bt/ac often discusses amperage/power limits as a function of heat dissapation through cable jackets. The power limits are capped out of concern a bundle of PoE cable ignites, so the wattage limits correspond to conductor size and number of 4-pair cables per bundle.  For example, bt/ac mandates use of Cat6, and so on.

So your question:

We would like to use the Cable as a regular DC transport cable . We need 100 watts @ 48 Volts about 2.5 amps 

If this is a single cable, it can likely handle it just fine. But if you're bundling multiple cables together, the answer changes.  See this chart (table 725.144 in the bt standard)

Also, can you run a larger conduction (bigger wire) Cat6 rather than Cat5?

We need 100 watts @ 48 Volts about 2.5 amps...

Btw, in a DC circuit, 2.5A @ 48V = 120W

To maintain 802.3bt Type 4, you must be terminating between a compliant PSE and PD. 

What is the device that needs power? Is it PoE? Or are you trying cannibalize the cat5 wire? If so you have to make sure your 2.5amp covers any peak voltage needed by your device.

Avoid the fire hazard and run the appropriate cable!

Well, it’s been awhile since I dove into the code books but as I recall, you should consider each conductor that is separated to be its own conductor. 

Guys will double, triple, quadruple up pairs on cables to increase amperage capacity.  It makes sense, until a single or couple of solid conductors break somewhere in the line.

Then, you have one or two small gauge wires carrying the load.  When you overload a conductor....guess what happens?  It generates heat/fire.

I’m sure PoE devices take this into account when single conductors or pairs become disabled, but just twisting them together does not make a “stranded” cable. 

Just my 2 Watts worth. 

Hi

Reading the news and technical information from afar, one hears talks about PoE standards for up to 100 watts,  the so-call PoE++ ..etc. The reality is that at those levels of power heat generation in a cable becomes substantial . Cat 5e predates PoE802.3 at for example let alone going full tilt at 100 watts... 

I will back off and pull a pair of 14 AWG cable ... Made for the purpose of power transmission that will easily carry up to 10 A .. Better to err on the safe side when risks of destruction are considerable.. Pulling those copper wires will be as painful as the proverbial toot ... but is is worth the pain and inconvenience.

Thanks all. Case closed!

:)