From Newsgroup: uk.d-i-y

I have a Hikvision 4-camera plus Network Video Recorder (NVR) system.
The cameras are all of the PoE (Power over Ethernet) type, and the NVR provides and controls the PoE. In total the cameras draw approximately
20 to 25W and the NVR is capable of providing 50W, so that's well
within spec.

None of the cameras are showing a picture on the monitor screen and the
NVR says they are not compatible - but it's all been working well for
years.

I also have a 4-port network switch in there but I'm not sure if it's
PoE. My question is, does it have to be?

The NVR is generating the power for the cameras so I thought that it
should all work because the switch is only passing the signal through
and isn't really anything to do with what the signal is.

So, do I need a PoE-compatible switch or not?
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From Newsgroup: uk.d-i-y

On 27/02/2026 20:19, Andy Smith wrote:

I have a Hikvision 4-camera plus Network Video Recorder (NVR) system.
The cameras are all of the PoE (Power over Ethernet) type, and the NVR provides and controls the PoE. In total the cameras draw approximately
20 to 25W and the NVR is capable of providing 50W, so that's well within spec.

None of the cameras are showing a picture on the monitor screen and the
NVR says they are not compatible - but it's all been working well for
years.

I also have a 4-port network switch in there but I'm not sure if it's
PoE. My question is, does it have to be?

The NVR is generating the power for the cameras so I thought that it
should all work because the switch is only passing the signal through
and isn't really anything to do with what the signal is.

So, do I need a PoE-compatible switch or not?

Did the problem start when you inserted the 4-port switch? If not, what changed between it working and it no longer working?

<https://support.huawei.com/enterprise/en/doc/DOC1000091883/d94e5308/determining-whether-a-switch-supports-the-poe-function>
implies that not all switches support PoE, though I can't work out
whether "supports" means "supplies power itself" or "allows power
supplied elsewhere to be passed from input port to the 4 output ports".
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From Newsgroup: uk.d-i-y

On Fri, 2/27/2026 3:19 PM, Andy Smith wrote:

I have a Hikvision 4-camera plus Network Video Recorder (NVR) system.
The cameras are all of the PoE (Power over Ethernet) type, and the
NVR provides and controls the PoE. In total the cameras draw approximately 20 to 25W and the NVR is capable of providing 50W, so that's well within spec.

None of the cameras are showing a picture on the monitor screen and the NVR says they are not compatible - but it's all been working well for years.

I also have a 4-port network switch in there but I'm not sure if it's PoE. My question is, does it have to be?

The NVR is generating the power for the cameras so I thought that it should all work because the switch is only passing the signal through and isn't really anything to do with what the signal is.

So, do I need a PoE-compatible switch or not?

That would be a good idea.

Example of an NVR with 56 watts of POE available

https://www.trendnet.com/store/products/8-port-nvr/8-channel-h265-4k-8mp-uhd-poe-nvr-TV-NVR1508

Examples of interconnect.

POE
|------- POE-CAM (works)
NVR |------- POE-CAM (works)
|------- POE-CAM (works)
|------- POE-CAM (works)

No POE # Even with POE-Passthrough, a single port
Passthru # from the source will not shove all available
POE 30W |------- POE-CAM (no power) # power through one output port. For example
|------- switch|------- POE-CAM (no power) # only 30W of 60W capacity, through one port.
NVR |---/ |------- POE-CAM (no power)
|---/ |------- POE-CAM (no power)
|---/

Or use a device with its own POE source. This product is apparently out
of production. I tried to find a picture of the adapter the switch
uses, but was not successful.

https://www.dlink.com/uk/en/products/dgs-1005p-5port-desktop-gigabit-poeplus-switch

External 53.5V @ 1.2A power adapter

Local
POE
POE |------- POE-CAM (works)
|------- switch|------- POE-CAM (works)
NVR |---/ |------- POE-CAM (works)
|---/ |------- POE-CAM (works)
|---/


You can also use injectors on the right hand side of the switch,
to power the cameras. Which would be a mess of wires,
but otherwise OK. The main advantage of the injector, would
be independent failures on powering (shorting one camera won't
affect the other cameras).

One of the reasons things like this are possible, is because
the up-to-four-twisted-pairs are transformer isolated.
This allows some tricks to pass additional functions (across 1,2,3,6)

It's hard to say where the ground reference is, in these pictures :-)
Maybe someone who has installed stuff like this can comment
on what they did and why.

Paul
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From Newsgroup: uk.d-i-y

Andy Smith wrote:

The NVR is generating the power for the cameras so I thought that it
should all work because the switch is only passing the signal through
and isn't really anything to do with what the signal is.

So, do I need a PoE-compatible switch or not?

There are some exceptions but if you plug the cameras into a switch,
that switch needs to provide PoE.

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From Newsgroup: uk.d-i-y

Andy Smith pretended :

I have a Hikvision 4-camera plus Network Video Recorder (NVR) system. The cameras are all of the PoE (Power over Ethernet) type, and the NVR provides and controls the PoE. In total the cameras draw approximately 20 to 25W and the NVR is capable of providing 50W, so that's well within spec.

None of the cameras are showing a picture on the monitor screen and the NVR says they are not compatible - but it's all been working well for years.

I also have a 4-port network switch in there but I'm not sure if it's PoE. My
question is, does it have to be?

The NVR is generating the power for the cameras so I thought that it should all work because the switch is only passing the signal through and isn't really anything to do with what the signal is.

So, do I need a PoE-compatible switch or not?

Thanks guys
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