PoE+ power issues on ~90m Cat6 run — need advice

[Hank Weng]

I’m running into an issue with PoE on a home setup. The cable run is close to 90m (Cat6, solid copper) and the camera sometimes reboots randomly. The switch is PoE+ (802.3at), and on paper it should be fine with the camera’s 12W draw, but I’m guessing voltage drop is the problem.

Has anyone here dealt with similar situations? Would you recommend adding a mid-span injector/repeater, or is it safer to upgrade to a PoE++ (802.3bt) switch?

Any real-world tips would be appreciated — not sure if I’m overthinking it or if this is a common issue.

 

[tigerwillow1]

I run a few cameras at the end of runs approaching the 100m limit, and one at 400 feet, with no reboot problems. The camera on the 400 foot run is a T180 that has a spec'd maximum draw of 11.8 watts. By the numbers, I don't think there should be a power problem due to the wire length. The round-trip resistance using 23 awg solid copper is 6.678 ohms (from an awg chart). At 12 watts you're drawing about a quarter amp, for a voltage drop of 1.67. I'd expect the camera to be easily tolerant of that. Do the reboots happen only when your cameras are drawing the most power, i.e. when the IR lights are running? If that's the case one suspect would be that you've reached to total power capability of the switch. If it happens during the day also, you could be looking at a cable termination problem, or flaky camera. I'd be swapping components to isolate where the failure is, like running a separate temporary cable to the camera, swapping the camera, different switch port, and so on.

 

[VorlonFrog]

I’m running into an issue with PoE on a home setup. The cable run is close to 90m (Cat6, solid copper) and the camera sometimes reboots randomly. The switch is PoE+ (802.3at), and on paper it should be fine with the camera’s 12W draw, but I’m guessing voltage drop is the problem.

Has anyone here dealt with similar situations? Would you recommend adding a mid-span injector/repeater, or is it safer to upgrade to a PoE++ (802.3bt) switch?

Any real-world tips would be appreciated — not sure if I’m overthinking it or if this is a common issue.

1. Not copper-clad aluminum (CCA) +1 point
2. Cat6 +1 point

Could be a few minor things:
a) swap PoE ports on the switch and see if the problem follows the camera - if it still occurs on other PoE ports, it's most likely at the camera
b) get some high-quality RJ-45 plugs made for solid wire (not for stranded!) and re-terminate both ends of the cable. Don't need to cut off a lot, maybe an inch or two from either end.
c) if problem STILL persists, and STILL follows the camera, then it's likely a bad PoE circuit board in the camera. Managed PoE switches could tell you via software what the current and voltage draw are, or you could use a hand-held meter to check the voltage at the camera end.

Hope this helps.