IP camera in the lift keeps going offline — PoE over the travelling loop
When the NVR shows the lift camera dropping and reconnecting, it is usually power, not network.
An IP camera reboots when its PoE voltage dips below what it needs, and a dip of a fraction of a second is enough. In a lift the dip comes from the loop.
Check the run length
Channeltech recommends up to 60 m of CAT6 Flat for an IP camera on PoE. If the flat section is longer, the voltage at the camera is marginal even before the cable ages. Measure it; the calculator gives the expected length from travel height.
Check the switch budget
A camera with IR and a heater can draw 10–15 W. On an 802.3af port (15.4 W at the switch, about 12.95 W at the camera) that is the whole budget. Move the camera to an 802.3at (30 W) port.
Check for a joint in the loop
A coupler inside the moving section has two more contact surfaces to loosen. Joints belong in the junction box, in the fixed section.
Check the cable
If the travelling section is round solid-core CAT6, a conductor is cracking; the reboots will get more frequent. Replace it with CC-8251G-90 and terminate with stranded-rated plugs.
Check the plug
A solid-core RJ45 on stranded cable makes intermittent contact under vibration; PoE is the first thing to suffer because it uses all four pairs at once. Re-terminate with plugs rated for stranded conductors.
