All 21,000 ports I administer have 802.3 standard PoE enabled at all times. Incidents of inadvertent powering are at zero. I think this is just a non problem.
Because of how ethernet works (differential signaling + signal transformers), PoE is effectively a wire at 48v connected to nothing if the device doesn't support it.
The only issue arises if somebody wires a patch cable completely wrong (neither A nor B), and manages to put one leg of passive PoE's +24v pair matched to one leg of the 0v pair. Which, will promptly smoke the signal transformer... assuming short circuit protection doesn't cut power first. This is why we killed passive PoE.
sodaclean|4 months ago
The only issue arises if somebody wires a patch cable completely wrong (neither A nor B), and manages to put one leg of passive PoE's +24v pair matched to one leg of the 0v pair. Which, will promptly smoke the signal transformer... assuming short circuit protection doesn't cut power first. This is why we killed passive PoE.