I have an exterior hikvision dome ip camera that stopped working in a 4 camera nvr setup. It worked fine for over a year.

I've tried a bunch of things to narrow down the problem. I updated the firmware on the nvr and power cycled it. I switched the nvr port for the camera to verify not a nvr port problem. I used the camera with a short cat6 close to the nvr and it worked as expected. The testing leads me to think it is an issue with the cat5e cable.

It seems like poe cables use 2 pairs for power and 1 pair for data leaving 1 spare pair of wires.

What is the best way to test the cat5e cable and determine the issue? I've crimped down on the connectors again in case there was something wrong, I've added connection enhancer to both the connector and the camera and it worked for a number of hours before it cut out again. Once it cuts out it doesn't seem to come back but taking down the camera, pulling the eth cord and putting it back in has allowed the camera to wake up and work for a number of hours.

I am thinking of putting a new connector on the camera end as the cat5e cord was a little bent and compressed under the camera so maybe over time the wires inside became damaged but it would be nice to know that wire x is the problem that I could use the spare pair and possibly get around a damaged wire within the cat5e cable.

I have a network cable tester it indicates that pair 3/6 are not working. I left the camera plugged in and the green lights cycled through the pairs skipping the 3&6. I tried it against a good cable and it cycled through all the pairs. It seems like there are some specialized poe testers on amazon not sure if that would help me anymore than this.

network cable tester

Here is a picture of a 5e box the installer used. I don't have a picture of the black 5e box but looking at the side of the cable it is marked:

SAE cat5e ansi/tia-568c.2 CMR 75C 4PR E308932 (UL) FT4 Enhanced Verified

sae cat5e box

I created a cat6 cable and tested with the tester then cut out pairs 4/5 7/8. I attached the camera to the nvr with this cable hoping it would just work since mode A poe only requires 1/2 3/6 and these pairs handle both data and power. I tested the cable with my tester and the 1/2 3/6 pair light up but using it to connect the camera didn't meet with success.

I had some trouble creating the cable and the network tester seemed to indicate that my cable had a bad 3/6 ( same problem as the camera ) so after what felt like hours of trying to create a cable I tried a known good cable again and it said bad 3/6 when using the two ports on the tester. I switched to using one port on the tester and one on the remote tester and then 3/6 illuminated. Seems like the 3/6 on the tester is a little iffy. I put the remote on the cable at the camera end and the tester on the cable at the nvr end and now all the pairs seem to be lighting up ok.

I let the network cable sit for the night and checked it and all pairs were reporting good. I took the tester and tried the camera again and this time I was able to see a bad 3/6 on the camera. Keeping the camera and cable still I swapped it to the nvr and it wasn't able to be detected so now I am pretty sure the problem is with the 3/6 pair in the cable that is oem to the dome camera. Looking at some youtube videos of people repairing the hikvision cameras it seems likely that the network cable is stranded. It seems like with stranded cables I should either install a punchdown female end or solder if I want to repair. For now I've ordered a replacement camera.

I am happy that the problem doesn't seem to be the house cable but disappointed that the dome camera would be made so cheaply that the cable would break after a couple years - probably designed to fail.

I retested the poe test since it seemed like the camera cable is damaged I wanted to give it another go when I have the camera/cable in a position where the pairs are testing good.

The poe cable test still failed to connect up the dome camera so it would seem the camera/nvr combo doesn't work on mode A. I also monitored the power output using the nvr on the camera - when I have a good cable the power output shows the port drawing power fairly quickly, when I put the mode A cable the power doesn't register.

I am pretty frustrated that the network tester I have has a finicky 3/6 light so I ordered a noyafa poe checker and a WiFi-Texas inline tester for poe. I'll play around with the camera a little bit more once my new tools arrive but I'll likely just install the replacement camera and shelve the damaged one until I get some more time to think about repairing it.

3 Answers 3


This sort of thing is often from not using appropriate wet-rated cable and connectors for exterior use. They work for a while and then get wet enough that they don't work anymore.

Proper POE cables (gigabit) in the modern era (which may or may not apply to this particular unit) use all 4 pairs for data and power via the magic of capacitive/transformer coupling for signals while power travels DC-coupled. In the "olden days" before defined, interchangeable 48V PoE all sorts of schemes were used with 12V and 24V power and "extra wires" in 100Base-T cables. There are no extra wires in 1000Base-T cables, they all get used. Your analysis of "one pair for data" only applies to ancient Half Duplex 10base-T connections. (Full-Duplex) 10BaseT and 100BaseT use two pairs for data (send/receive on separate pairs simultaneously)

Without knowing what you have for a network cable tester, it certainly would be worth trying it out to see if it shows anything.

  • I updated the question with cable details. I'll look into cat5e connectors that are rated for weather. The dome camera is only 2MP so I suspect gigabit doesn't factor into the equation. Now that I know 3&6 have the problem could I shift 3&6 to an unused pair or should I expect that all pairs are actually needed? My camera is the DS-2CD2120F. Commented Nov 14, 2021 at 0:37
  • 1
    Specs say: 1 RJ45 10M/100M Ethernet interface so yes, you can try swapping to a different pair, since data only needs 1,2 & 3,6 on those protocols.
    – Ecnerwal
    Commented Nov 14, 2021 at 0:43
  • 1
    Your camera also claims to conform to 802.3af POE spec, so this may provide some in-depth info on all the ways that can work: en.wikipedia.org/wiki/Power_over_Ethernet Neither cable appears to be exterior rated - they are both "riser" cable (CMR)
    – Ecnerwal
    Commented Nov 14, 2021 at 0:51
  • How do I know if this is modeA which uses the other 2 pairs for power or modeB where the other two pairs are unused? I looked at the waterproof connectors and while the camera has one end of a water proof connector the RJ45 that plugs into it is just a standard RJ45. Commented Nov 14, 2021 at 2:00
  • Test it with a 2-pair/4-wite cable (1,2 & 3,6) - if you don't throw useful stuff away too fast there's probably one or more in your old cables collection
    – Ecnerwal
    Commented Nov 14, 2021 at 2:10

I had problems getting my Hikvsion cameras to work, so bought one of these junk-tier testers

enter image description here

It solved my problems. It won't necessarily solve yours, but they are cheap enough to be worth trying.

Note that if you buy your cables from ebay/amazon seller, than most stuff sold nowadays is counterfeit garbage/CCA. Anything of this kind is best assumed to not up to spec (if a non-name brand) and a fraudulent copy of the real thing (if a name brand) UNLESS you bought it directly from a reputable seller. The longer the cable the more you will suffer voltage drop (you don't in fact need cat6 at all, the problem is your 'cat6' might not even be cat5e) and the more likely you are to have problems.

Also if you're not an experienced 'crimper', then you will probably, as I did, do it wrong. The cheap tool helps you instantly figure out you messed up.

  • The cable is original from the low volt installer, he did the crimping. I'll add an image of the cable/cable box that was used. That said he was more of a value option installer. I think this looks approximately like my tester. Commented Nov 13, 2021 at 21:11

Some misconceptions - Power over Ethernet (POE) can be misused.

The real meaning is power is sent over all four pairs, in addition to the data. Also, the two ends have an active negotiation about how much power is needed so the switch can budget. This accounts for voltage losses in the wire so the switch can send 48V, the POE device can get ~45 and still produce the 12V internally for itself. Range is up to 100 metres.
Your camera is expensive and will have this proper POE.

A less-common secondary meaning is "Power over Twisted Pair" where two pairs are used for data up to 100 Mbit, and the other two pairs are used for power only. There's no negotiation or step up/down of voltage, and its plain DC. The baluns used for this are small, light, and super-cheap. They are just wiring adapters, and the 100 Mbit limit is a giveaway as is using the remote-device's original PSU for power.
I've once fed 18V into a long wire to get 12V at the other end for a camera, and while it worked, the solution was absolutely rough and ropey.

In your case, the camera is fine because it works when plugged into a fresh cable. Great troubleshooting there, so focus on the other parts, the cable run.

I suspect that UV Sunlight or water or rodents or mechanical wear has damaged the conductors in the fixed run of cabling.

Depending on time, urgency, accessibility, etc you might choose to chop the cable at the halfway point and test each end of the run, then simply replace the end that is faulty. You absolutely need External rated cable if there is sunlight/rain/etc on the wire, or put the run inside conduit.

The other thing that could cause issues is movement. Since its a camera, its probably mounted up high maybe on a pole. Wind will cause movement which will flex and weaken wiring over time. This can be minimised by allowing slack in the cable, and to use the thicker gauge of wire (22 AWG is thicker than 24 AWG for example, and this also helps minimise POE voltage losses)

If you have an aerial run of wire, perhaps don't. Even when supported by a catenary cable the wire will flex and fail. If this is unavoidable, then make it easy to replace.

Also make sure there's water-shedding deflectors to stop rain running back the cable.

Connectors also are a source of weakness - the green death of corrosion on copper will prevent electrical connection. Aim to have waterproof connectiors whereever possible, or sealed junction boxes with water-shedding glands at passthrough holes.

  • Tangent story - I ran 3x indoor-rated cat5 from my house to my garage around 15 years ago, and the exposed pieces were run through boring garden hose. That cable was still working a decade later, with the only damage coming from puppy teeth on an unprotected run (which I temp-fixed with 8x scotch locks !!)
    – Criggie
    Commented Sep 29, 2022 at 23:42
  • Thanks - good thoughts. The problem is with the 3/6 pair in the cable that is oem to the dome camera. Looking at some youtube videos of people repairing the hikvision cameras it seems likely that the network cable is stranded. It seems like with stranded cables I should either install a punchdown female end or solder if I want to repair. The camera is sitting up on my shelf... see if I ever get around to repairing it. Commented Sep 29, 2022 at 23:50

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