If you intuitively think running a nice thick wire with a 12 volt supply means less losses than with POE, the numbers say otherwise. (Assumes I crunched the numbers correctly, which I sometimes don't, so corrections don't offend me).
Using a round-number 500 foot wire run, or 1000' total for the plus and minus conductors, 16 AWG wire run will have resistance of 4.016 ohms. 23 AWG cat6 resistance is 20.8 ohms, but since each side of the power is carried on 2 conductors, the resistance is actually 10.4 ohms for the wire run. Using a 12 volt load of 1 amp, the 16 gauge line will lose 4.016 volts. For the same power using POE, the current will be 0.25 amps for a loss of 2.6 volts. Power loss in the 16 AWG line is 4.016 watts. In the POE line it's 0.65 watts. Big difference!
I'm so surprised by the difference that it feels like a mistake, but I keep coming up with the same result. Same reason the power companies use zillion volt transmission lines. If the cable from the power source to the camera is fairly short, none of this matters much.
There needs to be some clarification and discussion as it pertains to your numbers so everyone has a better understanding and has both eyes wide open.
Because some will think the information is not subject to change as noted below.
Distance: The maximum distance for standard POE as spec’d by the IEEE is 100 meters / 320 feet. So to achieve 1000 feet requires mid spans to provide such distances which introduce what - more resistance and voltage drop.
This is why nobody who is remotely serious uses unpowered mid spans because it’s not possible to provide consistent GB speeds.
This is why those who use so called boosters that are not powered don’t see the same reliability & performance which adds even more voltage drop / resistance. There’s a thread going on right now and the OP has dozens of things at some 400 foot distance and can’t figure out why his shit don’t work or why it broke his shit?!?
Temperature: When heat rises so does resistance in any cable and thus voltage drop. The inverse is also true when it’s cold. This is also why shielded cable is used in certain applications when distance, bandwidth, and throughput is the primary goal. Because shield cable has a higher tolerance to heat build up (inside out) vs heat soaking (outside in).
This again highlights why some brands of cable costs so much more when compared to others. You’ll never see a data sheet for (testing) as it relates to temperature rise on cheaper cable.
POE: Your calculations also don’t take into account if someone is using passive vs active POE or the type of power over Ethernet such as POE AF, POE+ AT, POE++ BT. Where this whole thing goes down the toilet very fast is a cheap switch will not provide consistent amperage to each port. It may measure X volts but once a load is inserted the current does not meet the stated IEEE standards.
This is made even worse when people believe using the latest fad of Super POE (Think Dahua) to achieve 800 feet and beyond on a single line?!? The famous reply is whelps it’s 10 / 100 that’s plenty for a camera!
Really?!?
You know that thing that was created called a mid span?? That wasn’t designed and thought up by every major vendor in the world because it was fun. It was made because there was a true need to achieve 1000 feet and beyond while maintaining GB speed, bandwidth, throughput, and to spec latency!
Super POE like many of the things on the market was created to address edge case situations but everyone that gets suckered into this shitty tech always does what?!?
Buys and inserts a powered mid span to regenerate the data and power!
Data: I know your overall intent was to show case power loss as it pertains using different diameter cable. But it’s hard to ignore the fact 16 AWG is not doing what at the same time?
Data . . .
Nor does it explain if the same 16 AWG was also running 48 volts the loss you provided here would be negated. High voltage has been used to electrify our grid because doing the same on a 8” diameter wire would be impossible given the cost and shear weight.
High voltage allows smaller wires to carry less current and reduce resistance over extreme distances. This is exactly why the different POE standards exist now besides using fancy timing to carry data & power on the same wire if required by its spec.
All of the above assumes a person is using quality components, cable, and hardware. When anything in the chain is less than ideal think 24-36 AWG Ethernet cable?!
I was asked to come on site one day because a whole bank of switches died and took out the various POE devices from phones, cameras etc. As soon as I walked into the server room I knew immediately what happened. Some stupid fool wanted bright orange cable to achieve a
Look.
Well stupid found out 23 AWG shielded cable isn’t readily available in orange! So bought the same colour using 30 AWG!!
Just imagine seeing rows and rows of switches over heated, blown ports, end devices damaged because someone was too stupid to use a cable of same diameter!
Everyday someone is installing patch cables that are 24 AWG in a wall that isn’t CMR rated. Every day someone adds to this stupidity by chaining 2-4 more devices on the same small ass cable. To add insult to injury these same people will add a
Booster to break the 320 feet limit to only pile on to ultra stupid of using Super Duper POE at 10 / 100 Mb?!?
All of this sounds funny, it isn’t, because in this forum and many more this happens every single day.
Standards were created to achieve a known result. If people can’t even follow the most basics of using the correct material, hardware, etc. You can not expect to see consistent results that is reliable over a 25 year lifetime.
Spot on. Exactly what kept me from buying one. I put two of these in and have been very happy. ZERO issues. Not cheap, but not worried about them crapping the bed on me either. 