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Powering Two IP Cameras with One Twisted Pair POE Cable: Is it Feasible?

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Can I connect and power two PoE IP cameras over one existing twisted-pair cable, and how should the wires be split?

Yes, but only in some setups: you can split one 8-core cable into two 4-core links by making two RJ45 terminations, for example orange/green for one camera and blue/brown for the other, on both ends [#16569290] If the camera and PoE equipment comply with 802.3af, this can work with 2 pairs per camera [#16914263] However, many PoE cameras and recorders use different pair assignments or expect one camera per PoE port, so a simple splitter often fails with built-in PoE recorders [#18952313][#20001979][#21135115] In those cases the reliable fix is a proper PoE extender/splitter or switch designed for this use, such as ATTE xPoE-3-11 / xPoE-4-11-HS, with PoE disabled on the output that should not feed a camera [#20004419][#20019440] If you need a guaranteed solution and cannot run another cable, use dedicated PoE hardware rather than passive wire-splitting alone [#16568554][#18952318]
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  • #31 18952313
    Slawmobi
    Level 7  
    Posts: 3
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    Board Language: polish
    Good morning,
    I dig up the topic because I have a similar problem - one cable and two cameras, except that I have a POE recorder. I wanted to use the given adapter (SKU: AD-UTP / R) but on one auction I noticed the comment: "NOTE! - the device does not work with the POE recorder". Has anyone tested it?

    I also tried the options with two rj45 tips on pins 123 and 6 and it didn't work (not even one camera flashes)

    Thank you in advance for your response.

    Moderator's comment:
    The mentioned SKU: AD-UTO / R adapter does nothing but splits two pairs of twisted-pair cables into one RJ-socket and two pairs into the other. That is exactly the same as my colleague did later by clamping two RJ-ties on one cable. On the other hand, most cheap POE switches provide power via free pairs (brown and blue), which uses all wires for one device. So yes, my friend's cameras had communication, but they had no power supply. You can read a lot about it in the topics / announcements linked at the beginning of this thread.
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  • #33 18952324
    Slawmobi
    Level 7  
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    Is it the only possible option in such a configuration? It is an expense of about PLN 150, which is why I am asking.
  • #34 18952412
    sosarek

    Level 43  
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    You have PoE-powered cameras so this is the only proven option.
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  • #35 18952972
    mirekq
    Level 17  
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    Fix not xpoe-3-10, only xpoe-3-11 must be installed.
    xPoE-3-10 will not boot from the recorder.

    Here the guests made a description, the main difference is the minimum size and that xpoe-3-11 works with all switches, and xpoe-3-10 with ATTE switches, and you can power it via passive PoE (you give + 48V for the blue pair and minus for the brown pair)



    ATTE xPoE-3-10 https://youtu.be/ihbX8aqQFJw

    ATTE xPoE-3-11 https://youtu.be/3MNC4U_jUb0
  • #36 18953508
    sosarek

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    mirekq wrote:
    Fix not xpoe-3-10, only xpoe-3-11 must be installed.

    Fact, error in numbers ;)
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  • #37 18955245
    Slawmobi
    Level 7  
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    Thanks gentlemen for the answers and help. It's a pity because I thought there was an intermediate solution, because here, unfortunately, the cost is about PLN 200. I might consider running another cable
  • #38 19073656
    maddol
    Level 6  
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    I do not know if it is up to date, but even at long distances, a splitter for a couple of zlotys works. The downside is that you need to use two ports in the switch. For example Link

    I used it for distances over 50 meters and it's okay.
  • #39 19485534
    radam5
    Level 10  
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    I am coming back to the topic because I have a question.
    Can I additionally connect poe adapters to the given splitter?
    I have a camera connected with one rj45 cable to the router using poe adapters and now it's time for the other one and this splitter would be perfect
  • #40 19510034
    Mudzaf
    Level 7  
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    Good day. Dig out the topic. I have a Hikvision recorder, one twisted pair and I want to connect two Hikvision PoE cameras. I bought splitters, but it does not work because I do not have a switch, only a recorder. What it looks like when using XPOE-3-11. Will I be able to power it from the recorder?? How does the connection look like then. Splitter at the recorder, then the cable to the box outside, in the XPOE 3-11 box, and from the XPOE 3-11, then two cables for the camera??
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  • #41 19510037
    sosarek

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    From the recorder to input 3-11, from camera outputs.
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  • #42 19510047
    Mudzaf
    Level 7  
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    And the recorder will normally "see" two cameras, not one?
  • #43 19510050
    sosarek

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    It should be cheaper to buy a small PoE switch.
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  • #44 19510060
    Mudzaf
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    I want to avoid another 230v plug and there is probably no other way with a switch.
  • #45 19889930
    rudolf22
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    In practice, I am trying to do what my colleagues described, i.e. I connected the ATTE xpoe-3-11 to the DS-7608NI-K2 / 8p recorder. One camera can see me, while the other cannot be connected to be visible in the recorder.

    Has anyone managed to get it started?
  • #46 19889945
    sosarek

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    @ rudolf22 The problem may be a recorder with built-in PoE ports.
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  • #47 20001670
    snajdzio
    Level 10  
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    Hey @sosarek, I'm also on the subject, I bought a Switch PoE ATTE xPoE-3-11, for this I have a set with a recorder (built-in PoE ports) Hikvision NVR-4CH-POE IPCAM-B4 / T4 cameras. Unfortunately, the recorder can only see 1 camera, is there any chance that it would work properly and that I could see two cameras on this one cable? Or only the second cable as the only solution, unfortunately? I do not know if I should return this switch or something, but it can be understood ...
  • #48 20001979
    gkwiatkowski
    CCTV and Stationary Alarms specialist  
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    This is the problem of recorders with a built-in PoE switch. They only expect one camera per entrance.
    Maybe try to split the twisted pair and run one camera on orange and green pairs, and the other on blue and brown pairs.
  • #49 20002024
    snajdzio
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    Thanks beautiful, I will try, and it would make sense to use one more Switch PoE ATTE xPoE-3-11 from the recorder side to "split" into two sockets? The additional costs are known, but would it work?
  • #50 20002114
    gkwiatkowski
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    First of all, I don't know what would happen if PoE coming out of the recorder met with PoE coming out of the switch. Maybe nothing, and maybe smoke would fly out of something.
    You would have to look for a switch that transmits PoE to only one output, and the second output is without power and connect it to the second output from the recorder.
    Secondly, I do not know how the recorder will behave when it receives packets from the same camera for two inputs.
    You have to invest a little bit in testing.
  • #51 20003033
    snajdzio
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    Thank you @gkwiatkowski, if I knew that such circuses are with these recorders with built-in switches, I would immediately take the recorder and switch separately.
  • #52 20003362
    gkwiatkowski
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    We always recommend a separate recorder and a separate PoE switch. Less costs for replacement in time of failure and fewer problems with unusual configurations.
    Recorders with built-in PoE make sense with micro-facilities, where every bit of space counts. For example, monitoring a commercial kiosk. Four cameras on the corners, four twisted pairs, and one recorder box.
  • #53 20004334
    snajdzio
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    @gkwiatkowski Well, I also wanted to avoid a mess of equipment right behind the TV (later it turned out that I would be better off having a switch in the garage), but in this situation I would prefer to have it. So now I understand that if I replaced the recorder with one without a built-in switch, everything should go wrong? This is one solution, and the other is I unravel the cables and go on individual pairs of cables? Will both solutions work or are there any more risks?
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  • #54 20004419
    gkwiatkowski
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    Yes, these are two solutions to the problem.
    There is always a risk that some technical nuance will come out contrary to common sense. :)
    Check on the table how the cameras on the split twisted pair from the current recorder will work. There are even ready adapters so as not to cut the current plugs.

    It is best to bring all cables to the garage or utility room. Make a rock wardrobe there for all computer equipment, alarm, antenna, satellite, UPS, etc. And to the living room only bring HDMI and USB to the mouse from the recorder.
  • #55 20004677
    snajdzio
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    @gkwiatkowski thank you very much for all the answers, I will work. For the first solution, I ask the store if I replace the recorder after 14 days with such a switch, then I only assume it would end up with overvoltage of the plug ;) otherwise I have fun with splitting the cable. I hope to embrace it all ;) or that it will rather end up replacing the recorder ;) Keep ahead of your knowledge! Regards
    PS If I had difficulties, however, I would continue to bother with questions ;)
  • #56 20019440
    raffin
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    gkwiatkowski wrote:
    You would have to look for a switch that transmits PoE to only one output, and the second output is without power and connect it to the second output from the recorder

    This would be e.g. xpoe-4-11-HS / xpoe-4-11A-HS. In it, you can turn off the poe on selected outputs, but it is even more expensive.
  • #57 21133710
    borysb1
    Level 2  
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    And how? Does it know if the Hikvision DVR will work with one twisted pair split into 2 x 2 pairs per camera?
  • #58 21135115
    borysb1
    Level 2  
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    So I tested. The answer is no. The power standard used by my DVR (Hikvision HWN-4104MH-4P) is B, which means power goes on the other pairs (not the data ones). So you need all 4 pairs per camera.
    Optionally, you could try to make the cables so that the power pairs from one port plug in as the data pairs from the other, and vice versa, but I'd be a bit afraid of applying voltage from the DVR to the data pairs on the other port, so I won't try that. Unless someone would like to test this, or has knowledge if something could happen (in the sense of kicking the logger). So for now I'm stuck with pulling a separate cable :( .
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Topic summary

✨ The discussion revolves around the feasibility of powering two IP cameras using a single twisted pair cable with Power over Ethernet (PoE). Users explore various solutions, including the use of splitters and specific PoE switches like the ATTE xPoE-3-10 and xPoE-3-11. It is noted that while some cameras can operate on shared pairs, many require all four pairs for power and data transmission. Concerns about temperature resilience for outdoor switches and the limitations of built-in PoE recorders are also highlighted. Users share experiences with different brands and models, emphasizing the importance of compatibility with the 802.3af standard for successful operation.
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FAQ

TL;DR: 1 PoE port (15.4 W max, IEEE 802.3af) can feed two 6 W IP cameras if you split pairs or add a micro-switch; “use a small PoE switch, it fits in most camera boxes” [Elektroda, sosarek, post #18307167]

Why it matters: Saves running a second cable in finished walls.

Quick Facts

• IEEE 802.3af delivers 44–57 V DC, up to 15.4 W at the port [IEEE, 2018] • Mode A uses data pairs 1-2-3-6; Mode B uses spare pairs 4-5-7-8 [IEEE, 2018] • Typical turret IP cam draws 5–7 W with IR on [Elektroda, michualex, post #16569220] • ATTE xPoE-3-11 operates −25 °C to +55 °C and auto-negotiates PoE [ATTE datasheet] • Two-way RJ-45 splitter costs ≈ €5; outdoor PoE extender ≈ €40 [Allegro listing, 2023]

Can I power two PoE cameras over one Cat5e/Cat6 cable?

Yes, if the combined load stays below the port’s 15.4 W (802.3af) or 30 W (802.3at) budget and both cameras accept the same PoE mode. Split pairs or insert a tiny 3-port PoE switch like ATTE xPoE-3-11 [Elektroda, sosarek, post #18952318]

Which conductors carry power and data in PoE?

Mode A supplies power on data pairs 1-2-3-6; Mode B moves power to spare pairs 4-5-7-8. Your NVR ports default to Mode B, so all four pairs are busy [Elektroda, borysb1, post #21135115]

Why does my splitter give image from only one camera?

Your recorder’s PoE port sees two detection signatures in parallel and authenticates the first device only; the second stays offline [Elektroda, sosarek, post #18290908]

Will ATTE xPoE-3-11 work with a Hikvision PoE NVR?

No, tests show the NVR still sees a single camera; built-in PoE switches expect one device per port [Elektroda, snajdzio, post #20001670]

How much current can two cameras draw safely?

Keep total below 300 mA at 48 V (≈ 14.4 W). Two 6 W units leave ~3 W headroom for IR peaks [Elektroda, michualex, #16569220; IEEE, 2018].

Is crimping two RJ-45 plugs on one cable safe?

It works only if the switch powers on data pairs. If the camera needs Mode B, you’ll feed it data but no volts—result: dark screen [Elektroda, ryba884, post #16570792]

3-step: How do I split pairs without a switch?

  1. Crimp Plug A on pairs orange/white-orange and green/white-green.
  2. Crimp Plug B on pairs blue/white-blue and brown/white-brown.
  3. Connect each plug to a PoE port; link each camera to its matching pairs. [Elektroda, niepotrafie, post #16569290]

What is a low-cost alternative to branded extenders?

Generic 2×RJ-45 PoE combiner/splitters cost under €5 and work up to 50 m cable runs [Elektroda, maddol, post #19073656]
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