Answer: CCTV cameras typically use two wires: a power cable (12V/24V DC) and a video transmission cable (coaxial or Ethernet). The power cable supplies electricity, while the video cable transmits footage to the recorder. Some systems combine both via PoE (Power over Ethernet), reducing wiring to a single cable. Proper installation ensures stable performance and minimizes interference.
How Does the Power Wire Function in a CCTV Camera?
The power wire delivers electricity (usually 12V or 24V DC) to the camera. It consists of two conductors: positive (+) and negative (-). Incorrect polarity can damage the camera. For long distances, thicker gauges (e.g., 18/2 or 16/2) prevent voltage drop. Some setups use a separate power supply, while others rely on centralized systems. Weatherproof connectors are critical for outdoor installations.
Voltage stability is crucial for camera performance. Low-quality power supplies may cause flickering or intermittent shutdowns. For multi-camera setups, a centralized 12V DC power distribution box simplifies management. Solar-powered systems require charge controllers to regulate energy flow. Always use UL-listed adapters and avoid daisy-chaining multiple cameras on a single low-amperage circuit. For example, a 2A power supply can typically support 4-6 cameras drawing 0.3A each.
| Wire Gauge (AWG) | Max Distance (12V) | Recommended Use Case |
|---|---|---|
| 22/2 | 15 meters | Indoor short runs |
| 18/2 | 50 meters | Standard installations |
| 14/2 | 100 meters | Long-distance outdoor |
Why Are Coaxial and Ethernet Cables Used Differently?
Coaxial cables (analog) excel in short-distance analog video with noise resistance but lack power integration. Ethernet (digital) supports longer distances, higher resolutions, and PoE. Modern systems favor Ethernet for scalability and HD/4K support. Hybrid systems may use both, but PoE reduces clutter and costs. Always match cable type to camera and recorder compatibility.
Coaxial systems require separate power runs, increasing installation complexity. RG59 cables work well for 720p analog systems up to 300 meters, while RG6 handles 1080p over shorter distances. Ethernet’s twisted-pair design inherently rejects electromagnetic interference, making it ideal for industrial environments. Cat6a cables support 10Gbps speeds for future-proofing. When retrofitting old buildings, existing coaxial infrastructure can be adapted using HD-over-Coax converters, though latency may increase by 2-3 milliseconds.
“Proper wiring is the backbone of reliable CCTV systems. Always prioritize high-quality, shielded cables and adhere to voltage requirements. For PoE, calculate total power needs upfront—overloading a switch risks downtime. In harsh environments, invest in industrial-grade connectors. Testing saves hours of post-installation headaches.” — John Carter, Security Systems Engineer
FAQ
- Can I Use Existing Electrical Wires for CCTV?
- No—CCTV power lines require low-voltage DC. AC household wiring is incompatible and dangerous. Use dedicated 12V/24V cables or PoE.
- How Far Can CCTV Cables Run?
- Coaxial: 300 meters (with signal amplifiers). Ethernet: 100 meters (extendable with switches). Power cables: 50-100 meters, depending on gauge and voltage.
- Does Wire Gauge Affect Camera Performance?
- Yes—thicker gauges (lower AWG numbers) reduce voltage drop over long distances. For 12V systems beyond 50 meters, use 16/2 or 14/2 cables.