fred583
Young grasshopper
Thank you all for this information. Am I correct in assuming that if I have a ePoE Dahua NVR with ePoE cameras, that I would need to use the NVR ports rather than an external PoE switch to allow the ePoE feature?
Advantage to running individual cables to NVR vs POE switch and using a single cable back to the NVR
- Thread starter muddywaters7
- Start date
I'd add that ePOE also drops the transmission rate from 100 Mbps to 10 Mbps to achieve such long distances. What are the negatives of exceeding industry standards in terms of cable length??
Longer delay in so called real time video . . .
Longer delay in so called real time video . . .
fred583
Young grasshopper
Yes, apparently ePoE only degrades the Mbps after 300m, but your load capacity falls with distance as you would expect. I see now they have ePoE switches, but I only have two cable runs at 125m (410') so I would not need the switch. They claim regular PoE is only good for 100 m (328 ft). I will just use the NVR ePoE ports. I am making an assumption that the NVR internal ePoE switch is the same 48VDC situation as below.
That chart is interesting as in past ePOE reference material they were stating 50+ volts instead. The easiest way has always been to increase line voltage to transmit further while reducing current draw. The latest thinking is to use similar techniques of modulating the frequency and voltage to obtain longer distances.
Reference was also made to safety when choosing to use the NVR's POE or using a network switch with POE.
I didn't spot anyone mention the small in-line power bricks that often are required to supply 12v or 24v to larger PTZs. A while back I saw the failure rates for domestic electronic equipment and switch mode power supply units have one of the highest failure rates. Over time I've had at least two in-line laptop supply bricks fail and many USB and phone chargers. I'm surprised how often they run warm, some rather hot. Unlike NVRs or the larger POE network switches that mostly have cooling fans, these switch mode power bricks are usually sealed plastic boxes without any ventilation holes.
Here I've already got one Hikvision PTZ Speed Dome with it's 12v supply, and soon I'll be adding a Dahua PTZ with its 24V supply, both power supplies in the attic where it gets rather hot in summer. This thread has reminded me that a CCTV install is not a fit and forget, I'll need to keep a check as to how hot things are running, particularly these two in-line power bricks, but also the mains plug in 12v supplies for the network switches I'm using.
I didn't spot anyone mention the small in-line power bricks that often are required to supply 12v or 24v to larger PTZs. A while back I saw the failure rates for domestic electronic equipment and switch mode power supply units have one of the highest failure rates. Over time I've had at least two in-line laptop supply bricks fail and many USB and phone chargers. I'm surprised how often they run warm, some rather hot. Unlike NVRs or the larger POE network switches that mostly have cooling fans, these switch mode power bricks are usually sealed plastic boxes without any ventilation holes.
Here I've already got one Hikvision PTZ Speed Dome with it's 12v supply, and soon I'll be adding a Dahua PTZ with its 24V supply, both power supplies in the attic where it gets rather hot in summer. This thread has reminded me that a CCTV install is not a fit and forget, I'll need to keep a check as to how hot things are running, particularly these two in-line power bricks, but also the mains plug in 12v supplies for the network switches I'm using.