A good-quality security camera can deliver a poor image, or switch off at night, simply because of bad wiring. Security camera wiring comes down to two things: carrying the video to the recorder, and bringing 12 V power to the camera. Coaxial cable, RJ45 network cable, balun, power supply box: this simple guide helps you choose the right solution and avoid the most common mistakes.
Contents
HD analog or IP: two wiring approaches
Before choosing a cable, identify the type of camera:
- HD analog cameras (HDCVI, AHD, TVI): they connect to an XVR or DVR recorder. Video travels over a coaxial cable fitted with BNC plugs, or over a UTP network cable with baluns. The 12 V power arrives through a separate cable or through wires in the same cable.
- IP cameras: they transmit video digitally over an RJ45 network cable (Cat5e or Cat6). With a PoE switch or recorder, the same cable also carries the power. The Ethernet standard limits a single cable run to 100 m.
The Dahua HDCVI cameras in our security cameras section work in HD analog: they are wired with coaxial cable or with baluns.
Coaxial, balun or RJ45: the comparison
| Solution | For which cameras | Advantages | Things to watch |
|---|---|---|---|
| Coaxial cable (RG59 / RG6) + BNC plugs | HD analog | Classic solution, robust signal, available in a “coaxial + power” version | Thicker cable, harder to pull through conduits |
| UTP cable + baluns | HD analog | Thin, economical cable, long distances, spare pairs for power | One pair of baluns per camera, terminals must be tightened carefully |
| RJ45 network cable (Cat5e / Cat6) | IP | Video + power (PoE) in a single cable | 100 m maximum per run, crimping must be done carefully |
The balun, the practical solution
The 8 MP HD passive video balun, sold as a pair, replaces coaxial with a Cat5, Cat5e or Cat6 UTP cable. According to its product page, it is compatible with HDCVI, AHD, TVI and CVBS, needs no power, and carries video up to 300 m in 1080p and 200 m in 8 MP. One balun goes at the camera end, the other at the recorder end. It only carries video: power goes through other pairs of the cable or through a power supply close to the camera.
Coaxial and BNC plugs
If you stay with coaxial, each end gets a male BNC plug for RG59 / RG6 cable. A badly fitted plug (braid touching the core, core too short) causes a jumping image or a black screen: take the time to strip the cable properly.
12 V power: sizing it correctly
Two options: a small adapter per camera, or a centralized power supply box placed near the recorder. The box is tidier, easier to protect and easier to troubleshoot. To choose one:
- Add up the consumption of all the cameras (shown on their product sheet, in amps).
- Add a margin of about 20 to 30% (as a guide) for night-time infrared lighting and start-up.
- Choose a box with enough outputs: ideally one spare output.
Example: the product page of our TTLINK 12 V 5 A 4-channel power supply box notes that a Dahua 5 MP camera draws less than 0.6 A: four cameras stay well under 5 A. For an 8-camera system, the TTLINK 12 V 10 A 9-channel box offers a spare output. Both have a fuse per output and a lockable enclosure.
Watch out for voltage drop
At 12 V, a long, thin cable loses part of the voltage along the way. The result: a camera that keeps rebooting, infrared that does not switch on at night. As a guide, beyond about thirty metres, increase the cross-section of the power wires, double up the pairs used on a UTP cable, or move the power supply closer to the camera.
Brico MIM tip: on a plan, note the name of each camera, the length of its cable and its channel number on the recorder. Also label both ends of every cable: the day something breaks down, you will save precious time.
Running and connecting the cables
- Run cables inside conduit, especially outdoors: sun and rain damage bare cables.
- Keep video cables away from 230 V cables over long distances: interference degrades the image.
- Protect outdoor connections (BNC, baluns, power connector) in a waterproof box.
- Crimp connectors cleanly for IP cameras: our RJ45 8P8C connectors are suitable for Cat5, Cat5e and Cat6. Use the same colour order at both ends (most often T568B).
- Test each camera on the recorder before fixing the cables permanently.
Safety and mistakes to avoid
The 12 V side is extra-low voltage, but the power supply box connects to 230 V. Switch off the power at the electrical panel before any work, and leave the connection to the mains to a qualified electrician if you are not confident. For cameras mounted high up, work in pairs with a stable ladder.
Common mistakes: reversing + and − on the power supply, using an undersized adapter, leaving a connection exposed to rain, forgetting a balun at the recorder end, or mixing IP cameras and analog wiring without checking compatibility.
Frequently asked questions about camera wiring
Can I use a network cable for an HDCVI camera?
Yes, with one pair of baluns per camera. The UTP cable carries the video on one pair, and the other pairs can be used for the 12 V power.
Do I need one power supply per camera?
No. A centralized power supply box powers several cameras, within the limit of its total current and its number of outputs.
Why does my camera work during the day but not at night?
Often it is an underpowered supply or a voltage drop on a long cable: night-time infrared draws more current. Check the voltage at the camera end.
Do you deliver everywhere in Morocco?
Yes, Brico MIM delivers to every city in Morocco, with cash on delivery.
Everything to wire your cameras
Baluns, BNC plugs, RJ45 connectors, 12 V power supply boxes and enclosures: equip your installation.
0 comments