CCTV Cable Selection Guide: RG59 vs Cat6/Cat6A for IP Video Networks

As a UK-certified installer with years of experience in the security sector, I’ve witnessed the significant evolution of CCTV technology, particularly the shift from traditional analogue systems to sophisticated IP-based networks. One of the most critical, yet often overlooked, aspects of any successful CCTV deployment is the underlying cabling infrastructure. The choice between legacy RG59 coaxial cable and modern Cat6/Cat6A twisted pair cabling for IP video networks is not merely a preference; it’s a technical decision with profound implications for system performance, reliability, and future scalability.

This guide aims to provide a professional, engineering-grade comparison to help you make informed decisions for your next IP CCTV project.

The Legacy: RG59 Coaxial Cable

RG59 coaxial cable has long been the workhorse for analogue CCTV systems. Its design, featuring a central copper conductor, dielectric insulator, braided shield, and outer jacket, is specifically engineered for transmitting analogue video signals (baseband video) over distances with minimal signal degradation.

Key Characteristics & Limitations for IP Networks:

• Impedance: RG59 typically has a characteristic impedance of 75 Ohms. While perfectly suited for analogue video, this impedance mismatch is problematic for digital IP data packets, which require a 100 Ohm environment.
• Bandwidth: Designed for analogue signals, RG59 has a limited bandwidth capacity. Modern high-resolution IP cameras generate significant data streams that vastly exceed RG59’s inherent capabilities, leading to packet loss, latency, and reduced image quality.
• Signal Integrity: The primary function of RG59’s shielding is to protect against electromagnetic interference (EMI) for analogue signals. For high-frequency digital data, its shielding and construction are insufficient to prevent data errors and crosstalk in a multi-camera IP environment.
• Power Delivery: RG59 does not inherently support Power over Ethernet (PoE). While some hybrid cables incorporate power cores, these are separate and don’t leverage the integrated data and power delivery efficiency of modern twisted pair solutions.
• Balun Dependence: To use RG59 with IP cameras, baluns are required to convert the twisted pair signal from the camera to a format suitable for coaxial transmission, and then back again. This introduces additional points of failure, signal loss, and complexity, and is generally only considered for specific migration scenarios rather than new installations.

Conclusion for IP: From an engineering perspective, RG59 is fundamentally unsuitable for native IP video network installations. Its limitations in impedance, bandwidth, and power delivery make it a detrimental choice for achieving optimal performance from modern IP cameras.

The Modern Standard: Cat6/Cat6A Twisted Pair Cable

Category 6 (Cat6) and Category 6a (Cat6A) unshielded or shielded twisted pair (UTP/STP) cables are the industry standard for IP-based networking, including IP CCTV. Their design, comprising four individually twisted pairs of copper conductors within a single jacket, is optimised for high-speed digital data transmission.

Key Characteristics & Advantages for IP Networks:

• Impedance: Both Cat6 and Cat6A maintain a characteristic impedance of 100 Ohms, perfectly matching the requirements of Ethernet networks and IP cameras.
• Bandwidth & Data Rates:
  • Cat6: Supports frequencies up to 250 MHz and is rated for 1 Gigabit Ethernet (1GbE) over 100 metres. It can support 10 Gigabit Ethernet (10GbE) over shorter distances, typically up to 55 metres depending on the environment and alien crosstalk.
  • Cat6A: (Augmented Cat6) Supports frequencies up to 500 MHz and is specifically designed for 10 Gigabit Ethernet (10GbE) over the full 100-metre standard Ethernet segment length. Its enhanced design significantly reduces alien crosstalk (ANEXT), making it superior for high-density installations.
• Power over Ethernet (PoE): Cat6 and Cat6A cables are designed to deliver both data and electrical power simultaneously to network devices using PoE, PoE+ (802.3at), and PoE++ (802.3bt) standards. This simplifies installation, reduces cable clutter, and lowers overall infrastructure costs by eliminating the need for separate power supplies at each camera location.
• Future-Proofing: The higher bandwidth and superior noise rejection of Cat6A make it an excellent choice for future-proofing your CCTV infrastructure. As camera resolutions increase (e.g., 4K, 8K) and video compression technologies become more efficient but still demand robust bandwidth, Cat6A ensures your network can handle the increased data throughput without costly re-cabling.
• Cable Types: Available in various forms, including unshielded twisted pair (UTP) for typical environments, and shielded variations (e.g., F/UTP, S/FTP) for environments with high electromagnetic interference, which is common in industrial or outdoor CCTV deployments.

Critical Selection Checklist for IP Video Networks

When choosing cabling for your IP CCTV system, consider the following engineering principles:

1. Camera Resolution & Bitrate: Higher resolution cameras (e.g., 4MP, 8MP/4K) and higher frame rates generate significantly more data. Ensure your cable’s bandwidth can handle the aggregate data stream.
   • Calculation Example: A single 4K camera might require 15-25 Mbps. For a system with 10 cameras, this could be 150-250 Mbps, well within 1GbE, but requiring robust Cat6. If future 8K cameras are a consideration, 10GbE (Cat6A) becomes more appealing.
2. Distance: Standard Ethernet segments are limited to 100 metres. Beyond this, fibre optic cabling or Ethernet extenders (e.g., DSL over UTP) should be considered.
3. PoE Requirements: Determine the power draw of each camera (e.g., 802.3af for standard, 802.3at for PTZ or IR cameras). Ensure your chosen cable gauge (typically 23AWG for Cat6/6A) and PoE switches can supply adequate power without excessive voltage drop, especially over longer runs.
4. Environmental Conditions:
   • Indoor/Outdoor: Use UV-resistant, outdoor-rated (e.g., PE jacket) cable for external runs.
   • Fire Safety: For installations in public buildings or areas with fire regulations, specify Low Smoke Halogen Free (LSZH) cable to minimise toxic smoke and corrosive gas emission during a fire.
   • EMI/RFI: In environments with heavy machinery or electrical interference, consider shielded Cat6A (e.g., S/FTP) to protect signal integrity.
5. Future-Proofing: Always consider the long-term plan. While Cat6 might be sufficient for today’s 1GbE requirements, Cat6A offers a significant upgrade path to 10GbE without infrastructure changes, providing excellent return on investment over the system’s lifespan.

Conclusion

For any new IP video network installation, the choice is clear: Cat6 or, preferably, Cat6A twisted pair cabling is the superior and professionally recommended solution. RG59, despite its historical role in analogue CCTV, simply cannot meet the technical demands of modern digital IP networks.

Investing in high-quality Cat6 or Cat6A infrastructure ensures optimal video performance, reliable power delivery via PoE, and provides a robust, future-proof platform for your security investment. Always consult with a qualified UK-certified installer to design and implement a cabling solution tailored to your specific requirements.

📊 CCTV System Design Reference Infographic

Frequently Asked Questions (FAQ)

Q1: Can I re-use existing RG59 cable for new IP cameras with baluns? A1: While technically possible with specialised baluns that convert an IP signal to transmit over coax, it’s generally not recommended for new installations. This approach can introduce signal degradation, limit bandwidth, and complicate troubleshooting, ultimately undermining the performance benefits of IP cameras. It’s typically only considered for very specific, short-term migration strategies.

Q2: What’s the main benefit of Cat6A over Cat6 for CCTV? A2: The primary benefit of Cat6A is its guaranteed support for 10 Gigabit Ethernet (10GbE) over the full 100-metre distance, along with superior alien crosstalk performance. This makes it ideal for future high-resolution cameras (e.g., 8K) and ensures ample bandwidth for dense camera deployments without compromising performance. Cat6 only supports 10GbE over shorter distances (up to 55m).

Q3: Is shielding (STP/F/UTP) necessary for my Cat6/Cat6A CCTV cables? A3: For typical office or residential environments, unshielded twisted pair (UTP) Cat6 or Cat6A is usually sufficient. However, in environments with significant electromagnetic interference (EMI) or radio-frequency interference (RFI), such as industrial sites, near power lines, or in conduits with other electrical cables, shielded twisted pair (STP, F/UTP, S/FTP) is highly recommended to maintain signal integrity and prevent data errors.

Q4: Does the quality of the cable connectors (RJ45) matter as much as the cable itself? A4: Absolutely. The quality of connectors, patch panels, and keystones is just as crucial as the cable. A poorly terminated or low-quality connector can introduce signal loss, increase crosstalk, and become a significant point of failure, negating the benefits of high-grade cabling. Always use quality components and ensure correct termination practices, following TIA/EIA-568 standards.