brirec 12 days ago

The standard is, well, a standard, and that’s why PoE is safe in the first place. Adding per-port fuses won’t stop bad cable from burning, because the fuse would have to be sized for the rating of the PoE switch.

This is why you don’t want “fake” Cat6 etc. cable. I’ve seen copper-clad aluminum sold as cat6 cable before, but that shit will break 100% of the time and a broken cable will absolutely catch fire from a standard 802.at switch.

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esseph 12 days ago

There are also distance limits based on the type of cable used and the power drawn by the end device. The more you push that, the more heat you build. Shielding reduces that heat factor.

https://en.wikipedia.org/wiki/Power_over_Ethernet#Power_capa...

For Dayjob I power a lot of very expensive not-even-on-the-market-yet radios and other equipment via multiple PoE standards, mixed vendors, 2 pair, 4 pair, etc via POE and we have ran into all kinds of POE problems over the years.

POE fires do happen. Sometimes it's the cable, the connector, sometimes something happened to the cable run. Sometimes the gear melts.

https://www.powerelectronictips.com/halt-and-catch-fire-the-...

throw0101d 12 days ago

> There are also distance limits

It should be noted that there are two standards (of course) for Ethernet cabling, and one (TIA) officially hardcodes distances (e.g., 100m) but the other (ISO) simply specifies the signal-to-noise has to be a certain limits which could allow for longer distances (>100m):

* https://www.youtube.com/watch?v=kNa_IdfivKs

A specific product that lets you go longer than 100m:

* https://www.youtube.com/watch?v=ZY48KUAZKhM

esseph 12 days ago

As for your note about PoE standards btw, I remember an old joke, something along the lines of "The best thing about standards is that there are so many to choose from!"

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Non-standard implementations There are more than ten proprietary implementations.[49] The more common ones are discussed below.

https://en.wikipedia.org/wiki/Power_over_Ethernet#Non-standa...