I was just wondering when or if Hubitat would do something to make the POE limitation less of a problem. I have an environment where many devices benefit from POE and some require it, e.g. IP Phones. The environment is a combination of small business (RV Park) and residence. The potential to fry the Hubitat Hub by accidentally plugging into a POE ethernet port is a major discouragement to making a Hubitat investment.
I've not been concerned with POE yet. But I would think using the same plug, standard design rules would not allow such a condition to occur.
I don't know for sure but my guess is Hubitat is designed to ignore POE wires.
UPDATE:
Further investigation suggests with an improperly operating POE source, damage to a non POE device could be destructive.
It's the POE switch to decide whether to provide power, not the device.
An active POE switch should not send power to non-POE device.
If the switch is 802.3af/at compliant, there shouldn't be any issue.
Only dumb passive POE switch, if it still exists, will have the power always on.
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The device negotiates with the switch. I use POE for my hubs. All of my switches are POE and nothing gets fried.
Interesting.
I still believe a well thought out interface would not allow destructive failure even if the POE failed and supplied power all the time.
UPDATE. Apparently this is not the case. With my little knowledge of POE I suggest caution on any possible connection to Hubitat.
From everything I've read if you are using POE switches that follow 802.3af or 802.3at you should not run any risk. If your POE switches are NOT 802.3af or 802.3at compliant, then who knows. If the switches don't follow the standard they could do almost anything. Maybe there's a dongle that is the opposite of a POE injector? A POE extractor, for lack of a better term 
I posted this question because of the current Hubitat documentation. From the "Registration and setup" under getting started the following is listed " WARNING! Your Hubitat Elevation hub DOES NOT support PoE (Power over Ethernet). Attaching your hub to a PoE port will cause permanent damage and void the warranty."
Pardon the html tags, I simply copied and pasted from the documentation.
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Kudos for actually reading the manual. Odd. It must be there for a reason! Maybe they don't want to go through explaining the difference between 802.3af/at compliant PoE and nonstandard PoE? But if a standard PoE implementation fries an HE, then yeah, I agree - that's an issue.
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I would agree that provided the switch is designed correctly power would not be sent down the line. I never noticed that in the manual (Manual? I don't need no stinkin' manual!)
That said I use a poe splitter to power my hubitat (as do a lot of us) so that I can power it. They work well and are cheap. Honestly in all my years as a network engineer, I don't think I've ever come across a POE switch that didn't autosense what was being plugged into it. Not saying they don't exist, just I've never handled one. I wouldn't worry too much if you have a modern POE switch. You should also be able to turn POE off at that particular port if you're too worried.
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Exactly what they are called as I recall. AKA PoE splitter.
S.
I'm with @rlithgow1 and @brad5's posts. A standard 802.3af/at device won't send voltage down the wires unless the device at the other end is able to use it. I can't remember the exact method, but here's an explanation that jibes with what I recalled:
PoE Detection occurs like this "In order to avoid damage to non-PoE devices, a key component of the 802.3af PoE standard is detection. PSEs must be able to detect the presence of a PoE-enabled device before sending power, and must be able to detect when the powered device is no longer present and remove power. To achieve accurate detection, a low-level detection current is sent from the PSE through the cable and the response is analyzed to determine if a compliant device is attached."
There is such a thing as Passive PoE though, and I think it might be possible, using a cheap Amazon "Passive PoE injector" to smoke something. But a standards compliant PoE switch from Ubiqiuiti, Trendnet, Netgear or whomever shouldn't damage your Hubitat or any other Ethernet device. Nor should a PoE injector from PoE Texas, for example.
But a good PoE splitter is probably the best way to power the Hubitat in any case, as it's essentially a DC block right in front of the ethernet port with a pre-block DC split to put power into the DC in.
S
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POE= No worries, 3 HE hubs on a cisco 2960-s POE switch, no fires/smoke and plenty of other devices that are not POE hanging off the switch.
Z-wave is another story.
Passive POE will fry ports. The industry suffered because anyone who put power on a datacable could call it power over Ethernet and technically would not mislead the consumer.
Eventually a standard was devised, later on two actually, and both of the IEEE standards are compatible with non powered devices.
802.3af and 802.3bt both require the power delivery device to carefully measure current to detect if power is supposed to be delivered, generally with a 25k ohm resistance measured over two pins, if a current is detected with a specific curve at 7khz then the PD port determine that the other side has a current transformer and start delivering current, again very carefully monitoring the requested current draw.
These two standards will not damage Ethernet ports. All other stuff, usually referred to as passive POE is likely to damage ports.
Some light reading The Hazards of Passive PoE | Ethernet Alliance
I can also forward the standard of you want to read more. Hubitat is probably safer by saying no POE at all, and let knowledgeable users make their own decisions.
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Yeah I think you called it. Iām not sure I would make any different decision frankly
Thanks to everyone for the input. After 30+ years in IT the restriction seemed a little odd but the discussion regarding passive POE is very plausible to me as well as the contrast in the standards. I tell my friends I'm getting old (long on opinion and short on patience). I read the legal fodder before I sign and even the purchase agreement for Hubitat includes the POE acknowledgement. I've learned not to trust software updates so I will make sure I use a non-POE port or provide some other isolation.
I heard from Hubitat technical support today. As was suggested by others the real problem is ethernet devices which do not properly test the POE requirement. The really nice thing here is that technical support does respond to questions and the community is a valuable resource. Here is a portion of the response I received. "This is still a problem for current versions of Hubitat Elevation. Some devices are "smart" enough not to send power to non-compatible devices, however we do not have a list of which devices are smart, so you may cause permanent damages if your devices doesn't protect the non PoE clients."
My first Hubitat has been ordered.
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